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BACKGROUND
The successful treatment of schizophrenic behavior using antipsychotic tranquilizers such as chlorpromazine has stimulated research to find other neuroleptic agents having improved biological profiles. One such class of compounds is the hexahydropyrido[4,3-b]indoles. The basic ring structure is ##STR1## and the stereochemistry at positions 4a and 9b may be cis or trans. Examples of hexahydropyridoindoles that are useful as tranquilizers, neuroleptic agents, analgesics, sedatives, muscle relaxants and hypotensive agents are given in the following U.S. Pat. Nos.: 3,687,961; 3,983,239; 3,991,199; 4,001,263 and 4,141,980.
It has now been discovered that novel hexahydro-trans-4a,9b-pyrido[4,3-b]indoles substituted at the 5 position with an aryl group and the 2 position with an aminoalkyl group or an amidoalkyl group exhibit potent neuroleptic activity.
SUMMARY
The neuroleptic agents of the present invention are (+) enantiomeric, a mixture of (+) and (-) enantiomeric or (±) racemic hexahydro-trans-4a,9b-pyridoindole derivatives of formula I ##STR2## and the pharmacologically acceptable salts thereof.
The optically pure (-) enantiomeric derivatives of formula I have considerably less neuroleptic activity than the corresponding (+) enantiomers or racemic mixtures. Consequently, the pure (-) enantiomers are excluded from the present invention but their mixture with varying amounts of the (+) enantiomers are included.
The variable substituents of formula I are defined as follows:
j and k independently are 1 or 2;
m is 1 to 8;
X and Y are independently selected from H, F, Cl, Br, OCH 3 , CH 3 or CH 2 CH 3 ;
R 1 is H, alkyl of 1 to 5 carbons, Ph or the mono or disubstituted form of Ph, the mono or disubstituent being F, Cl, Br, OCH 3 , CH 3 or CH 2 CH 3 ;
R 2 is H, alkyl of 1 to 5 carbons, Ph, CH 2 Ph or the mono or disubstituted form of Ph or CH 2 Ph, the mono or disubstituent being F, Cl, Br, OCH 3 , CH 3 or CH 2 CH 3 ;
and R 3 is H, alkyl of 1 to 5 carbons, Ph, CH 2 Ph, alkanoyl of 1 to 8 carbons, alkoxycarbonyl of 2 to 8 carbons, benzoyl, phenylacetyl, alkylsulfonyl of 1 to 8 carbons, phenylsulfonyl or the mono or disubstituted form of Ph, CH 2 Ph, benzoyl, phenylacetyl, or phenylsulfonyl, the mono or disubstituent being F, Cl, Br, OCH 3 , --OCH 2 O--, CH 3 or CH 2 CH 3 .
Several types of derivatives are preferred because they exhibit exceptional neuroleptic activity. These include the derivatives wherein CHR 1 NR 2 R 3 is CH 2 NHCOCH 3 , the derivatives wherein CHR 1 NR 2 R 3 is CH 2 NHCOPh or the mono or disubstituted form thereof and the derivatives wherein j and k are both 1, X is F at the 8 position and Y is para or ortho F.
Preferred embodiments include the following derivatives:
(+) or (±) 2-(N-acetyl-1'-amino-n-but-4'-yl)-5-(p-fluorophenyl)-8-fluoro-2,3,4,4a,5,9b-hexahydro-trans-4a,9b-1(H)-pyrido[4,3-b]indole of (+) enantiomeric or racemic formula I wherein j and k are both 1, m is 3, CHR 1 NR 2 R 3 is CH 2 NHCOCH 3 , X is 8-F and Y is para-F;
(+) or (±) 2-(N-acetyl-1'-amino-n-pent-5'-yl)-5-(p-fluorophenyl)-8-fluoro-2,3,4,4a,5,9b-hexahydro-trans-4a,9b-(H)-pyrido[4,3-b]indole of (+) enantiomeric or racemic formula I wherein j and k are both 1, m is 4, CHR 1 NR 2 R 3 is CH 2 NHCOCH 3 , X is 8-F and Y is para-F;
(+) or (±) 2-(N-acetyl)-1'-amino-n-hex-6'-yl)-5-(p-fluorophenyl)-8-fluoro-2,3,4,4a,5,9b-hexahydro-trans-4a,9b-1(H)-pyrido[4,3-b]indole of (+) enantiomeric or racemic formula I wherein j and k are both 1, m is 5, CHR 1 NR 2 R 3 is CH 2 NHCOCH 3 , X is 8-F and Y is para-F;
(+) or (±) 2-(N-acetyl-1'-amino-n-hept-7'-yl)-5-(P-fluorophenyl)-8-fluoro-2,3,4,4a,5,9b-hexahydro-trans-4a,9b-1(H)-pyrido[4,3-b]indole of (+) enantiomeric or racemic formula I wherein j and k are both 1, m is 6, CHR 1 NR 2 R 3 is CH 2 NHCOCH 3 , X is 8-F and Y is para-F;
(+) or (±) 2-(N-acetyl-1'-amino-n-oct-8'-yl)-5-(P-fluorophenyl)-8-fluoro-2,3,4,4a,5,9b-hexahydro-trans-4a,9b-1(H)-pyrido[4,3-b]indole of (+) enantiomeric or racemic formula I wherein j and k are both 1, m is 7, CHR 1 NR 2 R 3 is CH 2 NHCOCH 3 , X is 8-F and Y is para-F;
(+) or (±) 2-(N-acetyl-1'-amino-n-non-9'-yl)-5-(p-fluorophenyl)-8-fluoro-2,3,4,4a,5,9b-hexahydro-trans-4a,9b-1(H)-pyrido[4,3-b]indole of (+) enantiomeric or racemic formula I wherein j and k are both 1, m is 8, CHR 1 NR 2 R 3 is CH 2 NHCOCH 3 , X is 8-F and Y is para-F;
(+) or (±) 2-(N-benzoyl-1'-amino-n-but-4'-yl)-5-(p-fluorophenyl)-8-fluoro-2,3,4,4a,5,9b-hexahydro-trans-4a,9b-1(H)-pyrido[4,3-b]indole of (+) enantiomeric or racemic formula I wherein j and k are both 1, m is 3, CHR 1 NR 2 R 3 is CH 2 NHCOPh, X is 8-F and Y is para-F;
(+) or (±) 2-(N-(o-methoxybenzoyl)-1'-amino-n-but-4'-yl]-5-(p-fluorophenyl)-8-fluoro-2,3,4,4a,5,9b-hexahydro-trans-4a,9b-1(H)-pyrido[4,3-b]indole of (+) enantiomeric or racemic formula I wherein j and k are both 1, m is 3, CHR 1 NR 2 R 3 is CH 2 NHCOC 6 H 4 OCH 3 (o), X is 8-F and Y is para-F;
(+) or (±) 2-(N-ethoxycarbonyl-1'-amino-n-but-4'-yl)-5-(p-fluorophenyl)-8-fluoro-2,3,4a,5,9a-hexahydro-trans-4a,9b-1(H)-pyrido[4,3-b]indole of (+) enantiomeric or racemic formula I wherein j and k are both 1, m is 3, CHR 1 NR 2 R 3 is CH 2 NHCOOC 2 H 5 , X is 8-F and Y is para-F;
(+) or (±) 2-(N-acetyl-1'-amino-n-but-4'-yl)-5-phenyl-2,3,4,4a,9b-hexahydro-trans-4a,9b-1(H)-pyrido[4,3b]indole of (+) enantiomeric or racemic formula I wherein j and k are both 1, m is 3, CHR 1 NR 2 R 3 is CH 2 NHCOCH 3 and X and F are both hydrogen.
The invention also includes pharmaceutical preparations of pharmaceutically acceptable carriers and derivatives of formula I which can be used as neuroleptic agents as well as a method of treating psychotic disorders of a patient by the administration of an efficacious amount of a derivative of formula I to the patient.
DETAILED DESCRIPTION
For the purposes of this discussion, the instant pyrido[4,3-b]indole nucleus ##STR3## Accordingly, derivatives of formula I are represented by ##STR4## and the starting material pyrido[4,3-b]indole of formula II ##STR5## is represented by ##STR6##
The derivatives may be synthesized by first coupling the known starting material pyrido[4,3-b]indoles of formula II with the side chain synthon of formula IIIa or IIIb as described in Scheme A or with the acid reagent of formula IIIc as depicted in Scheme B and then by modifying the side chains of these coupling products.
In Scheme A and the discussion about it, the substituents X, Y, Z and m of the formulas are as defined above, Hal is chloro, bromo, p-toluenesulfonyl or methanesulfonyl, R 1 and R 2 are other than phenyl or mono or disubstituted phenyl and R 4 is alkyl of 1 to 5 carbons, Ph or mono or disubstituted phenyl, the mono or disubstituent being F, Cl, Br, OCH 3 , CH 3 or CH 2 CH 3 .
Scheme A
Preparation of Hexahydro-trans-pyridoindole Derivatives of Formula I ##STR7##
Reaction 4a is acylation or sulfonylation. R 2 is H and R 3 is an acyl or sulfonyl group.
Reaction 4b is alkylation then acylation or sulfonylation. R 2 is alkyl, benzyl or mono or disubstituted benzyl and R 3 is an acyl or sulfonyl group.
Reaction 4c is dialkylation. R 2 and R 3 are alkyl, benzyl or mono or disubstituted benzyl.
Preparation of a derivative of formula I wherein R 2 or R 3 is phenyl or mono or disubstituted phenyl is given in Scheme B.
Composite Reaction 1 (1a and 1b) is the coupling of the side chain synthons IIIa and IIIb and the pyridoindole nucleus and is well known in the art. The product of the reaction is the nitrile intermediate (1a) or ketone intermediate (1b) which must be further modified to produce a derivative of formula I. Reactions 2, 3 and 4 illustrate this conversion and are also well known.
Both reaction 1a and reaction 1b may be conducted by reacting at ambient to reflux temperature about an equi-molar amount of the starting material pyridoindole of formula II and the side chain synthon of formula IIIa or IIIb in an inert polar solvent such as methanol, ethanol, tetrahydrofuran, glyme, lower alkyl ketone, dimethylformamide or dimethylsulfoxide containing at least an equivalent amount of neutralizing agent such as sodium bicarbonate, pyridine or triethylamine and allowing the reaction to proceed until it is substantially complete. The product of the reaction, which will be the nitrile intermediate from reaction 1a or the ketone intermediate from reaction 1b, may be purified using standard techniques such as extraction, crystallization, chromatography or any combination thereof.
Reaction 2 is the conversion of the ketone intermediate to the oxime intermediate. It may be conducted by reacting the ketone with hydroxylamine in ether, tetrahydrofuran, ethanol, methanol or other similar solvent. The oxime intermediate may be purified using standard techniques such as extraction, crystallization, chromatography or any combination thereof.
Reaction 3 is the reduction of the nitrile or oxime intermediate to a derivative of formula I wherein CHR 1 NR 2 R 3 is a primary amine, CHR 1 NH 2 . It may be accomplished using known reagents such as lithium aluminum hydride in ether or tetrahydrofuran or hydrogen over palladium on charcoal or other similar catalyst in methanol, ethanol or ethyl acetate.
The primary amine derivative may be converted to a derivative of formula I wherein R 2 or R 3 is other than hydrogen by use of composite reaction 4 (reaction 4a, 4b or 4c given below respectively).
To prepare a derivative of formula I wherein R 2 is hydrogen and R 3 is an acyl or sulfonyl group, i.e., alkanoyl, alkoxycarbonyl, benzoyl, phenylacetyl, alkylsulfonyl, phenylsulfonyl or the mono or disubstituted form of benzoyl, phenylacetyl or phenylsulfonyl, the primary amine derivative of formula I is acylated or sulfonated using Schotten-Baumann or diimide (DCC) "acylation" conditions. The Schotten-Baumann "acylation" may be conducted by reacting the primary amine derivative with the appropriate aryl or sulfonyl halide (Cl, Br) in an inert solvent such as methylenechloride, lower alkyl ketone, dimethylformamide or dimethylsulfoxide containing a neutralizing agent such as sodium bicarbonate, pyridine or triethylamine. The dicyclohexyl carbodiimide (DCC) "acylation" may be conducted by reacting the primary amine derivative with the carboxylic or sulfonic acid corresponding to the desired acyl or sulfonyl group and with DCC in a solvent such as methylene chloride, chloroform, diethyl ether or tetrahydrofuran. The product from either method may be purified using standard techniques such as extraction, crystallization, column chromatography or any combination thereof.
To prepare a derivative of formula I wherein R 2 is alkyl, benzyl or mono or disubstituted benzyl and R 3 is an acyl or sulfonyl group, the primary amine derivative of formula I is first alkylated then acylated or sulfonated. The alkyl, benzyl or mono or disubstituted benzyl intermediate may be prepared using the appropriate alkyl, benzyl or mono or disubstituted benzyl chloride, bromide, iodide or sulfate. The "acylation" reaction is conducted as described above.
A derivative of formula I wherein R 2 and R 3 are alkyl, benzyl or mono or disubstituted benzyl is prepared by dialkylating or sequentially monoalkylating the primary amine derivative of formula I. For example to prepare a derivative wherein R 2 and R 3 are equal, at least two equivalents of the alkyl, benzyl or mono or disubstituted benzyl chloride, bromide, iodide or sulfate are added to the primary amine derivative in an inert solvent such as methanol, ethanol, glyme or tetrahydrofuran containing a neutralizing agent such as sodium bicarbonate, pyridine or triethyl amine. The dialkylated derivative is purified using standard techniques such as extraction, crystallization, column chromatography or a combination thereof. To prepare a derivative wherein R 2 and R 3 are not equal, the same procedure is used except that the monoadduct is first prepared which is alkylated with the second desired alkyl, benzyl or mono or disubstituted benzyl chloride, bromide, iodide or sulfate. Of course, a monoadduct derivative of formula I wherein R 2 is alkyl, benzyl or mono or disubstituted benzyl and R 3 is H, is prepared by the same procedure using an appropriate ratio of reactants.
Scheme B represents another route for the preparation of some derivatives wherein R 2 and R 3 are hydrogen, alkyl, phenyl, benzyl or mono or disubstituted phenyl or benzyl. In Scheme B and the discussion about it, the substituents X, Y, Hal, j, k and m are as previously defined; R 1 is hydrogen and R 2 and R 3 have the restricted definitions just set forth.
Scheme B
Another Route to Some Hexahydro-trans-pyridoindole Derivatives ##STR8##
Reaction 5 is the coupling of the starting material pyridoindole of formula II and the acid reagent of formula IIIc, HO 2 C(CH 2 ) m-1 CONR 2 R 3 to produce the acylate. The coupling conditions are well known. The starting material pyridoindole is treated with the acid reagent in the presence of dicyclohexyl carboiimide (DCC conditions) in a solvent such as chloroform, methylene chloride, diethyl ether or tetrahydrofuran until the coupling is substantially complete. Alternatively the starting material pyridoindole may be treated with the acyl halide corresponding to the acid reagent under Schotten-Baumann conditions described above. The acylate is purified using standard techniques such as extraction, crystallization, column chromatography or any combination thereof.
Reaction 6, is the conversion of the acylate to the desired derivative of formula I. Use of a reducing agent such as lithium aluminum hydride in an inert solvent such as ether, tetrahydrofuran or glyme will reduce the both amide functions at the 2 position and CONR 2 R 3 to the desired amine functions. After quenching the remaining hydride with a reagent such as water, alcohol or a hydrated inorganic salt the derivative may be purified using standard techniques such as extraction, crystallization, column chromatography or any combination thereof.
The acid reagent IIIc may be prepared by coupling the appropriate amine, HNR 2 R 3 , with the appropriate half acid, half ester HO 2 C(CH 2 ) m-1 CO 2 CH 3 under DCC or Schotten-Baumann conditions followed by hydrolysis of the ester function of the resulting half ester, half amide.
The optically active or racemic derivatives may be prepared using the corresponding optically active or racemic starting material pyridoindoles. The racemic derivatives may also be resolved using methods known in the art for resolving racemic amines, see Fieser et. al. "Reagents for Organic Synthesis" Wiley and Sons, Inc., New York (1967), Vol. 1, page 977 and references cited therein. For example, formation of the amine salt using D-pyroglutamic acid produces the diastereomers which may then be separated by fractional crystallization. The resolved (+) enantiomer can be obtained by basifying the resolved salt.
The pharmacologically acceptable salts of the derivatives may be prepared by reaction with about an equivalent of an organic or mineral acid in either aqueous or non-aqueous solution. Such acids include hydrochloric, hydrobromic, hydroiodic, sulfuric, phosphoric, acetic, lactic, citric, tartaric, succinic, maleic and gluconic acids. The salt may be isolated by removal of the solvent in vacuo or in an appropriate case, by precipitation.
The derivatives are useful as neuroleptic agents in the treatment of mental disorders and illnesses including schizophrenia, psychoses and neuroses. Symptons requiring such treatment include anxiety, aggression, agitation, depression, hallucinations, tension and emotional or social withdrawal. In general, the derivatives exhibit major tranquilizing activity but have fewer side effects than the drugs presently in use.
The derivatives can be formulated in a variety of pharmaceutical compositions which contain the derivative alone or in combination with pharmaceutical carriers such as inert solid diluents, aqueous solutions or various non-toxic, organic solvents and in dosage forms such as gelatin capsules, tablets, powders, lozenges, syrups, injectable solutions and the like. Such carriers include water, ethanol, gelatins, lactose, starches, vegetable oils, petroleum jelly, gums, glycols, talc, benzoyl alcohols, and other known carriers for medicaments. If desired, these pharmaceutical preparations may contain additional material such as preserving agents, wetting agents, stabilizing agents, lubricating agents, absorption agents, buffering agents and isotonic agents.
The derivatives may be administered to a patient in need of treatment by a variety of conventional routes of administration such as oral, intravenous, intramuscular, subcutaneous or intraperitoneal. In general, small doses will be administered initially with a gradual increase in the dose until the optimum level is determined. However, as with any drug the particular dose, formulation and route of administration will vary with the age, weight and response of the particular patient and will depend upon the judgment of his attending physician.
In the usual course of treatment a dose of a derivative of approximately 0.1 mg per day to 100 mg per day will provide effective treatment for the human patient. When the derivative has a prolonged effect, the dose can be administered every other day or in 1 or 2 divided doses per week.
The tranquilizing activity of the derivatives may be determined using the well known standard procedure-antagonism of amphetamine-induced symptoms in rats. This method has excellent correlation with human efficacy and is taught by A. Weissman, et. al., J. Pharmacol. Exp. Ther. 151, 339 (1966) and by Quinton, et al., Nature, 200, 178, (1963). As illustrated below this method shows that the derivatives have excellent tranquilizing activity compared to the standard test drug, chlorpromazine.
So called "intrinsic" tranquilizing activity of the derivatives may be determined using the method of Leysen et. al., Biochem. Pharmacol., 27, 307 (1978). The ability of the drug to inhibit 3 H-spiroperidol binding to dopamine receptors is measured and the results correlate with the relative pharmacological potencies of drugs affecting behavior mediated by dopamine receptors (Burt, et. al., Molecular Pharmacol., 12, 800 (1976)). As given below, this intrinsic method shows that the derivatives have excellent neuroleptic activity.
The present invention is illustrated by the following examples. It will be understood, however, that the invention is not limited to the specific details of these examples.
EXAMPLE 1
(±)2-(1'-cyano-n-prop-3'-yl)-5-p-fluorophenyl-8-fluoro-2,3,4,4a,5,9b-hexahydro-trans-4a,9b-1(H)-pyrido[4,3-b]indole (nitrile intermediate 1)
A stirred suspension of 8-fluoro-5-(p-fluorophenyl)-2,3,4,4a,5,9b-hexahydro-trans-4a,9b-1(H)-pyrido[4,3-b]-indole (starting material pyridoindole sm) (1 g, 3.49 mM), gamma-bromo-butyronitrile, (0.723 g, 4.88 mM), anhydrous sodium carbonate, (2.1 g, 20.9 mM), potassium iodide, (0.289 g, 1.74 mM), in methyisobutylketone, (40 ml), under nitrogen was refluxed for 16 hours. The reaction mixture was cooled to room temperature and evaporated in vacuo to dryness. The resulting white solid was partitioned between water (40 ml) and chloroform (50 ml). The phases were separated and the aqueous phase extracted with chloroform (50 ml). The organic layers were combined, dried (MgSO 4 ), and evaporated in vacuo to give a pale yellow oil. Treatment of the oil with hydrogen chloride gas in acetone (40 ml), gave upon filtration and washing with acetone (10 ml) 0.813 g, (60% yield) of the above titled nitrile intermediate (1) as a white solid, mp 245°-249° C. (HCl salt).
CHN analysis calc'd for C 21 H 21 N 3 F 2 .HCl; C-64.67, H-5.42, N-10.77. Found: C-64.38, H-5.71; N-10.71.
EXAMPLE 2
(±)2-(1'-amino-n-but-4'-yl)-5-(p-fluorophenyl)-8-fluoro-2,3,4,4a,5,9b-hexahydro-trans-4a,9b-1(H)-pyrido[4,3-b]indole (Derivative 2)
To a stirred suspension of lithium aluminum hydride (0.167 g, 4.4 mM) in diethyl ether (35 ml), under nitrogen, was added the nitrile intermediate (1) of Example 1 (0.781 g, 2.0 mM) at a rate sufficient to maintain the reaction temperature 28°-30° C. (15 min). After stirring for 4 hr at ambient temperature, Glaubers Salt (Na 2 SO 4 .10H 2 O) (1.2 g, 4 mM) was added portion wise over a 10 min peroid. The white solid was filtered and washed with diethyl ether (10 ml) and the filtrate evaporated in vacuo to give a pale yellow oil. Treatment of the oil with hydrogen chloride in ether (35 ml), gave upon filtration and washing with ether (20 ml), 0.498 g, (64% yield) of the above titled Derivative (2) as a white solid mp 224°-227° C. (HCl salt).
CHN analysis: calc'd for C 21 H 25 N 3 F 2 .2.5H 2 O.HCl; C-53.28, H-6.38; N-8.87. Found: C-52.98, H-5.94, N-8.66.
EXAMPLE 3
(±)2-(N-acetyl-1'-amino-n-but-4'-yl)-5-(p-fluorophenyl)-8-fluoro-2,3,4,4a,5,9b-hexahydro-trans-4a,9b-1(H)-pyrido-[4,3-b]indole (Derivative 3)
To a stirred solution of the Derivative (2) of Example 2 (0.315 g, 0.803 mM), triethylamine (0.44 ml, 3.2 mM), and methylene chloride (10 ml), under nitrogen at 2° (ice bath), was added acetyl chloride (0.063 ml 8.8 mM) in 5 ml methylene chloride at a rate sufficient to maintain the reaction temperature 2°-5° C. After stirring at ambient temperature for 2 hours the reaction mixture was poured onto saturated sodium bicarbonate solution (30 ml). The phases were separated and the aqueous phase extracted with methylene chloride (30 ml). The organic layers were combined, dried (MgSO 4 ), and evaporated in vacuo to give a pale yellow oil. Treatment of the oil with hydrogen chloride in isopropanol (5 ml) gave upon filtration 0.230 g, (65% yield) of the above titled Derivative (3) as a white solid, mp 243°-245° C. (HCl salt).
CHN analysis: calc'd for C 23 H 27 ON 3 F 2 .HCl; C-63.36, H-6.47, N-9.63. found; C-63.25, H-6.48, N-9.73.
EXAMPLE 4
(±)2-(N-phenylsuccinamoyl)-5-(p-fluorophenyl)-8-fluoro-2,3,4,4a,5,9b-hexahydro-trans-4a, 9b-1(H)pyrido[4,3-b]indole (Acylate 4)
To a stirred solution of 4a,9b-trans-8-fluoro-5-(p-fluorophenyl)-2,3,4,4a,5,9b-hexahydro-trans-4a,9b-1(H)-pyrido[4,3-b]indole (starting material pyridoindole sM) (1 g), N-phenylsuccinamic acid (acid reagent AR4) 9 g) and methylene chloride (20 ml), under nitrogen at 2° C. (ice bath) is added dicyclohexylcarbodiimide (1 g). The reaction mixture is allowed to stir at 2°-4° C. for about 30 minutes then at ambient temperature for 2 hours. The reaction mixture is then cooled to 2° C. (ice bath) and the white solid dicyclohexyl urea may be filtered and washed with cold methylene chloride (5 ml). The filtrate is evaporated in vacuo and the residue may be purified by crystallization or chromatographic techniques to yield the above titled Acylate (4).
EXAMPLE 5
(±)2-N-phenyl-1'-amino-n-but-4'-yl)-5-(p-fluorophenyl)-8-fluoro-2,3,4,4a,5,9b-hexahydro-trans-4a,9b-1(H)pyrido[4,3-b]indole (Derivative 5)
To a stirred suspension of lithium aluminum hydride (0.2 g) in diethyl ether (40 ml), under nitrogen is added Acylate (4) of Example 4 (1 g) at a rate sufficient to maintain the reaction temperature at 28°-30° C. After stirring for about 2 hours at ambient temperature, Glaubers Salt (Na 2 SO 4 .10H 2 O) (2 g) may be added portion-wise. The white solid may be filtered and washed with diethyl ether,. The filtrate is evaporated in vacuo and the residue purified by crystallization or chromatographic techniques to yield the above titled Derivative (5).
EXAMPLES 6 through 17
The following Derivatives were prepared by following the procedures of Examples 1 through 5 and by substituting the appropriate side chain synthon or acid reagent for side chain synthon (SCSl) of Example 1 or acid reagent (AR4) of Example 4. Other Derivatives may be prepared by substituting the appropriate starting material pyridoindole of formula II and by substituting the appropriate side chain synthon of formula IIIa or b or appropriate acid reagent of formula IIIc for the corresponding material in Examples 1 through 5.
The pyridoindole nucleus used for almost all the synthesized derivatives is 5-(p-fluorophenyl)-8-fluoro-2,3,4,4a,5,9b-hexahydro-trans-4a,9b-1(H)-pyrido-[4,3-b]indole. Consequently unless otherwise indicated, the name of the Derivative of each of the following examples is given as the 2-position substituent (the side chain) and it will be understood that the above pyridoindole nucleus is part of each name. For instance, the complete name of the Derivative of Example 6 is 2-(N-acetyl-2-aminoethyl)-5-(p-fluorophenyl)-8-fluoro-2,3,4,4a,5,9b-hexahydro-trans-4a,9b-1(H)-pyrido[4,3-b]indole.
__________________________________________________________________________ 1. calc'ed Empirical Analysis 2. foundExampleName mp °C. formula C H N__________________________________________________________________________ 6 (±) 2-(N-acetyl-2-amino- 229-33 C.sub.21 H.sub.23 ON.sub.3 F.sub.2 1. 59.24 6.15 9.86ethyl) hydrochloride salt . H.sub.2 O . HCl 2. 59.34 5.78 9.97 7 (± ) 2-(N-acetyl-1'-amino- 224-7 C.sub.22 H.sub.25 ON.sub.3 F.sub.2 1. 61.31 6.08 9.75n-prop-3-yl) hydrochloride . 1/2 H.sub.2 O . HCl 2. 61.50 6.32 9.30salt 8 (±) 2-(N-acetyl1'-amine-n- 237-40 C.sub.24 H.sub.29 ON.sub.3 F.sub.2 1. 61.59 6.89 8.97pent-5'-yl) hydrochloride . H.sub.2 O . HCl 2. 61.82 6.40 8.80salt 9 (±) 2-(N-acetyl-1'-amino-n 204-8 C.sub.25 H.sub.31 ON.sub.3 F.sub.2 1. 60.05 7.00 8.40hex-6'-yl) hydrochloride . 2H.sub.2 O . HCl 2. 60.13 6.58 8.33salt10 (±) 2-(N-acetyl-1'-amino- 217-21 C.sub.26 H.sub.33 ON.sub.3 F.sub.2 1. 62.39 7.24 8.39n-hept-7' -yl) hydrochloride . 11/4 H.sub.2 O . HCl 2. 62.41 7.09 8.34salt11 (+) enantiomer of 2-(N- 253-6 same as Derivative (3)acetyl-1'-amino-n-but-4-yl) (Derivative 3) hydro-chloride salt12 (-) enantiomer of 2-(N- 255-8acetyl-1'-amino-n-but-4'-yl)(Derivative 3) hydrochloridesalt13 (± ) 2-(N-benzoyl-1'-amino-n- 259-62 C.sub.28 H.sub.29 ON.sub.3 F.sub.2 1. 62.97 6.22 7.86but-4'-yl) hydrochloride . 2H.sub.2 O . HCl 2. 63.11 6.00 8.03salt14 (± ) 2-N-ethoxycarbonyl-1'- amorphous C.sub.24 H.sub.29 O.sub.2 N.sub.3 F.sub.2 1. 60.68 6.57 8.87amino-n-but-4'-yl) hydro- . 1/2H.sub.2 O . HCl 2. 60.46 6.49 8.79chloride salt15 (± )2-[N-(o-methoxybenzoly)- foam C.sub.29 H.sub.31 O.sub.2 N.sub.3 F.sub.2 1. 63.78 6.27 7.691' -amino-n-but-4'-yl]hydro- . H.sub.2 O . HCl 2. 63.50 6.13 7.55chloride salt16 (± ) 2-(N-p-toluenesulfonyl- amorphous C.sub.28 H.sub.31 O.sub.2 N.sub.3 SF.sub.2 1. 60.36 5.97 7.541'-amino-n-but-4'-yl) hydro- . 1/2H.sub.2 O . HCl 2. 60.13 6.00 7.25chloride salt17 (± ) 2-(N-acetyl-1' amino-n- 238-240 C.sub.23 H.sub.29 ON.sub.3 . 1.l 65.38 7.63 9.94but-4'-yl)-5-phenyl-2,3,4,- . 11/4H.sub.2 O 2. 65.34 7.09 9.864a,9b-hexahydro-trans-4a,9b-1(H)-pyrido[4,3-b]indole__________________________________________________________________________
EXAMPLE 18
Antagonism of Amphetamine Symptoms in Rats
Test Procedures and Results
The effects of the above examples of Derivatives on prominent amphetamine-induced symptoms were studied in rats by a rating scale modeled after the one reported by Quinton and Halliwell, and Weissman. Rats were placed individually in a covered plastic cage measuring approximately 26 cm.×42 cm×16 cm. After a brief period of acclimation of the cage, the rats in each group, commonly, five animals per dose level, were treated subcutaneously (s.c.) with a selected dose of the Derivative to be tested. They were then treated 1, 5 and 24 hrs. later with d-amphetamine sulfate, 5 mg./kg. intraperitoneally (i.p.). One hour after amphetamine was given, each rat was observed for the characteristic amphetamine behaviour of moving around the cage. On the basis of dose-response data after amphetamine it was possible to determine the effective dose of the compound necessary to antagonize or block the characteristic amphetamine behavior of cage movement for fifty percent of the rats tested (ED 50 ). The time of rating chosen coincides with the peak action of amphetamine which is 60-80 min. after dosing. The results (ED 50 ) of tests on the Derivatives of Examples 2, 3, 6-17 and subcutaneously administered chlorpromazine, a comparative drug, are given in Table 1 below.
TABLE 1______________________________________Rat Amphetamine Test ED.sub.50 (mg/kg)Example 1 hr. 8 hr. 24 hr.______________________________________ 2 17.7 4.5-11.5 17.7 3 0.02 0.006 0.66 6 0.11 0.36 1 7 NT NT NT 8 0.01 0.004 0.4 9 0.023 0.002 0.03210 0.09 0.018 0.0511 0.02 0.006 0.2812 (-) enantiomer >1 >1 >113 0.1-0.3 0.01-0.03 0.3-114 0.05 0.02 0.315 0.45 0.18 116 1 1 NT17 1.0-0.1 1.0-0.1 1.0-0.1Chlorpromazine 5.3 8.5 32 (s.c.)______________________________________ NT is not tested.
EXAMPLE 19
Inhibition of 3 H-Spiroperidol Binding to Dopamine Receptors
Test Procedures and Results
The relative affinity of the derivatives for receptors was studied using 3 H-spiroperidol (spiperone) as the labeled ligand following the method of Leysen et. al. Biochem Pharmacol, 27, 307-316 (1978). The procedure was as follows:
Rats (Sprague-Dawley CD males, 250-300 g., Charles River Laboratories, Wilmington, MA) were decapitated, and brains were immediately dissected on an ice-cold glass plate to remove corpus striatum (˜100 mg./brain). Tissue was homogenized in 40 volumes (1 g.+40 ml). of ice-cold 50 mM. Tris (tris[hydroxymethyl]aminomethane; (THAM) .HCl buffer pH 7.7. The homogenate was centrifuged twice at 50,000 g. (20,000 rpm) for 10 minutes with rehomogenization of the intermediate pellet in fresh THAM buffer (same volume). The final pellet was gently resuspended in 90 volumes of cold, freshly prepared (<1 week old) stock solution, 50 mM Tris buffer pH 7.6 containing 120 mM NaCl (7014 g./l.), 5 Mm KCl (0.3728 g/l.), 2 mM CaCl 2 (0.222 g./l.), 1 mM MgCl 2 (0.204 g./l.), 0.1% ascorbic acid (1 mg./ml.) and 10 micro M pargyline (100 micro l. stock/100 ml. buffer; stock= 15 mg./10 ml. DDW**). Ascorbic acid and pargyline were added fresh daily. The tissue suspension was placed in a 37° C. water bath for 5 minutes to insure inactivation of tissue monoamine oxidase and then kept on ice until used. The incubation mixture consisted of 0.02 ml. inhibitor solution (the desired concentration of the derivative to be tested in stock solution). 1.0 ml. tissue homogenate and 0.10 ml label ( 3 H-spiroperidol, New England Nuclear 23.6 Ci/mmole), prepared so as to obtain 0.5 nM in the final incubation medium (usually diluted 2.5 μl. stock to 17 ml DDW**). Tubes were incubated in sequence for 10 minutes at 37° C. in groups of three, after which 0.9 ml. of each incubation tube was filtered through Whatman FG/B filters using a high vacuum pump. Each filter was placed in a scintillation vial, 10 ml. of liquid scintillation fluor was added and each vial was vigorously vortexed for about five seconds. Samples were allowed to stand over night, until filters were translucent, vortexed again and then counted 1.0 minute for radioactivity. Binding was calculated as femtomoles (10 -15 moles) of 3 H-spiroperiodol bound per mg. protein. Controls (vehicle or 1 butaclamol, 10 -7 M; 4.4 mg. dissolved in 200 μl. glacial acetic acid, then diluted to 2.0 ml, with DDW for 10 -4 M stock solution, kept refrigerated), blank (d-butaclamol, 10 -7 M; 4.4 mg./2 ml. for 10 -4 M stock solution, same protocol as 1-butaclamol), and inhibitor solutions were run in triplicate. The concentration reducing binding by 50% (IC 50 ) was estimated on semi-log paper. Insoluble drugs were dissolved in 50% ethanol (1% ethanol incubation).
The results using the derivatives of Examples 2, 3, 6-17 and subcutaneously administered chlorpromazine are reported below in Table 2 as the nanomolar concentration required to produce 50% inhibition of 3 H-Spiroperidol binding.
TABLE 2______________________________________Inhibition of .sup.3 H Spiroperidol Binding to Dopamine______________________________________ReceptorsExample IC.sub.50 (nM) 2 24 3 13 6 16 7 10 8 9 9 810 911 4.712 100013 1914 1115 1416 2717 16Chlorpromazine 51 (s.c.)______________________________________
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Medicinal agents classed as 2-(aminoalkyl or amidoalkyl)-5-aryl-hexahydro-trans-4a,9b-1(H)-pyrido[4,3-b]indole derivatives have been synthesized and found to have neuroleptic activity.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the circuit configuration and layout of a pixel area of an active matrix display device in which thin-film transistors are used and source lines formed above gate lines. In particular, the invention relates to the structure of an auxiliary capacitor.
2. Description of the Related Art
In recent years, techniques of forming thin-film transistors (TFTs) on an inexpensive glass substrate have been made rapid progress. This is because of increased demand for the active matrix liquid crystal display device.
In the active matrix liquid crystal display device, thin-film transistors are provided for respective ones of hundreds of thousands to millions of pixels that are arranged in matrix form and the charge entrance and exit to each pixel is controlled by the switching function of the thin-film transistor.
A liquid crystal is interposed between each pixel electrode and an opposed electrode, to form a kind of capacitor. Therefore, image display is realized by controlling the quantity of light passing through the liquid crystal panel by varying the electro-optical characteristic of the liquid crystal by controlling the entrance and exit of change to and from this capacitor with the thin-film transistor.
The capacitor having the above structure has a problem that since the voltage held by the capacitor gradually decreases due to current leakage, it changes the electro-optical characteristic of the liquid crystal and deteriorates the contrast of image display.
A common measure to solve the above problem is a configuration in which an additional capacitor called an auxiliary capacitor is provided in parallel with the capacitor including the liquid crystal and charge equivalent to charge that is lost due leakage etc. is supplied to the capacitor including the liquid crystal.
FIG. 1 is a circuit diagram of a conventional active matrix liquid crystal display device. The active matrix display circuit is generally divided into three parts: a gate driver circuit 2 for driving gate lines (i.e., gate lines, scanning lines) 4 , a data driver circuit 1 for driving source lines (i.e., data lines, source lines or signal lines) 5 , and an active matrix circuit 3 that is provided with pixels. The data driver circuit 1 and the gate driver circuit 2 are generically called a peripheral circuit.
In the active matrix circuit 3 , a number of gate lines 4 and source lines 5 are provided so as to cross each other and pixel electrodes 7 are provided at the respective intersecting points. A switching element (thin-film transistor) 6 is provided to control charge that enters or exits from each pixel electrode 7 . Selection is made between the top-gate thin-film transistor (the gate electrode is formed above the active layer) and the bottom-gate thin-film transistor (the active layer is formed above the gate electrode) in accordance with the necessary circuit structure, the manufacturing process, the required characteristics, and other factors. Further, as described above, to prevent a variation in pixel voltage due to leak current, an auxiliary capacitor 8 is provided in parallel with each pixel capacitor.
On the other hand, the conductivity of the thin-film transistor is varied by illumination with light. To prevent this phenomenon, it is necessary to cover each thin-film transistor with a light-interruptive coating (black matrix). The light-interruptive coating is formed so as to also cover the portions between the pixels to prevent color or brightness contamination between the pixels and a display failure due to a disordered electric field at pixel boundaries.
So, the light-interruptive coating assumes a matrix shape and hence is called a black matrix (BM). At first, in favor of advantages in a manufacturing process, the black matrix was provided over the substrate (opposed substrate) that opposes the substrate on which the active matrix circuit is formed. However, recently, because of the need for increasing the area of each pixel (aperture ratio), it is proposed to provide the black matrix over the substrate on which the active matrix circuit is formed.
SUMMARY OF THE INVENTION
Various proposals haven made of the structure of the auxiliary capacitor. However, it is difficult to obtain a large capacitance while maintaining the area of the open portion (light-transmissive portion) of each pixel.
The present invention has been made in view of the above circumstances in the art, and an object of the invention is therefore to provide a structure of an auxiliary capacitor which can provide a large capacitance while maintaining the area of the open portion (light-transmissive portion) of each pixel.
According to one aspect of the invention there is provided an active matrix liquid crystal display device comprising a thin-film transistor having a source region to which a pixel electrode is electrically connected; a drain electrode connected to a drain region of the thin-film transistor and formed in the same layer as a source line, the drain electrode having a pattern that covers 50% or more of an active layer of the thin-film transistor; and an auxiliary capacitor formed by using the drain electrode.
With the above configuration, the aperture ratio of the pixel can be increased because the auxiliary capacitor is formed above the thin-film transistor.
Another aspect of the invention attains the above object by forming a conductive light-interruptive film over the active-matrix-side substrate, keeping it at a constant potential, and using it as one electrode of the auxiliary capacitor. Since originally the light-interruptive film does not transmit light, the aperture ratio does not decrease even if it is used as one electrode of the auxiliary capacitor.
The active matrix liquid crystal display device of the invention comprises:
(1) a thin-film transistor;
(2) a gate line and a source line formed above the gate line;
(3) a conductive film serving as a light-interruptive film and kept at a constant potential;
(4) a metal wiring, connected to a drain region of the thin-film transistor and made of the same layer as the source line; and
(5) an interlayer insulating film formed between the source line and the conductive film, and comprising at least two insulating layers.
In the invention, the thin-film transistor may be of either the top gate type or the bottom gate type as long as the above conditions are satisfied. This is, since the main improvements of the invention relate to the structure above the source line, the structure below the source line (i.e., the positional relationship between the gate line and the active layer) is irrelevant. Also, the interlayer insulating layer may consist of three or more layers.
According to another aspect of the invention, in the above configuration, an auxiliary capacitor having the metal wiring and the conductive film (light-interruptive film) as electrodes and at least the lower insulating layer of the interlayer insulating film as a dielectric is formed in a region where the upper insulating layer of the interlayer insulating film is removed by etching. The dielectric may consist of two or more insulating layers.
According to a further aspect of the invention, in the above configuration, the conductive film (light-interruptive film) overlaps with the metal wiring and has a portion that is in contact with the lower insulating layer.
In the two aspects of the invention just mentioned above, it is effective to employ, as the main component of the lower insulating layer, silicon nitride that is produced stably in semiconductor processes and has a large relative dielectric constant. In this case, the dielectric of the auxiliary capacitor may be composed of only a silicon nitride layer or may have a multi-layer structure of a silicon nitride film and some other coating (for instance, a silicon oxide film).
In this case, the dielectric is made thinner and the use of silicon nitride having a large dielectric constant realizes a large capacitance. In the invention, the thickness of the silicon nitride layer is set at 1,000 Å or less, preferably 500 Å or less.
In this configuration, since the silicon nitride film covers the active matrix circuit from above the source lines, the barrier function of silicon nitride resulting from its high moisture resistance, high resistance to ions, etc. can be utilized effectively.
In the invention, it is effective to form the upper insulating layer by using an organic resin, which is easy to be planarized (for instance, polyimide, polyamide, polyimideamide, epoxy, or acrylic). In this case, since the organic resin is insufficient in barrier function (the moisture resistance, the resistance to ions, etc. are low), it is desirable that the lower insulating layer be made of a material exhibiting a superior barrier function such as silicon nitride, aluminum oxide, or aluminum nitride.
In the invention, it is effective to provide the metal wiring in a region of each pixel where disclination (alignment disorder of liquid crystal molecules due to irregularity or a lateral electric field) is prone to occur. Among various kinds of disclination, disclination due to dust or the like can be eliminated by cleaning of a manufacturing process. However, disclination caused by irregularity in the device structure (for instance, irregularity in the vicinity of a pixel electrode contact) or a lateral electric field cannot be eliminated thoroughly. It is not proper to use, for display, a pixel region where disclination occurs. Conventionally, such a region is covered with a light-interruptive film so as not to serve for display. In contrast, in the invention, the auxiliary capacitor can be provided in such a region, whereby the available area of each pixel can be utilized efficiently.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a circuit diagram of a common active matrix circuit;
FIGS. 2A and 2B are top views showing a manufacturing process of an active matrix circuit according to a first embodiment of the present invention;
FIGS. 3A-3E are sectional views showing the manufacturing process of an active matrix circuit according to the first embodiment;
FIGS. 4A and 4B are top views showing a manufacturing process of an active matrix circuit according to a second embodiment of the invention;
FIG. 5 shows how disclination occurs;
FIGS. 6A and 6B are top views showing a manufacturing process of an active matrix circuit according to a third embodiment of the invention;
FIGS. 7A and 7B are a schematic top view and a circuit diagram of a thin-film transistor according to fourth embodiment of the invention;
FIGS. 8A and 8B are top views showing a manufacturing process of an active matrix circuit according to the fourth embodiment;
FIGS. 9A and 9B are top views showing a manufacturing process of an active matrix circuit according to a fifth embodiment of the invention;
FIG. 10 is a top view of an active matrix circuit according to a modification of the fifth embodiment;
FIGS. 11A-11D are sectional views showing a manufacturing process of the active matrix circuit according to the fifth embodiment; and
FIGS. 12-14 are top views showing the configuration of an active matrix circuit according to a sixth embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiment 1
FIGS. 2A-2B and FIGS. 3A-3E are top views and sectional views, respectively, showing a manufacturing process according to this embodiment. The reference numerals used in FIGS. 2A-2B and FIGS. 3A-3E correspond to each other. Numerical values of the film thickness etc. used in the following embodiments are just examples and are not necessarily optimum ones, and a party to practice the invention is completely allowed to change those values when necessary.
First, a 500-Å-thick amorphous silicon film is formed over a glass substrate 11 by plasma CVD or low-pressure CVD. It is preferable to form a 3,000-Å-thick silicon oxide film as an underlayer film on the glass substrate 11 by sputtering or plasma CVD. The underlayer film may be omitted in a case of using a quartz glass substrate.
Then, an active layer 12 of a thin-film transistor is obtained by converting the amorphous silicon film into a crystalline silicon film by a known annealing technique such as heating or laser light illumination and etching the crystalline silicon film.
Then, a 1,000-Å-thick silicon oxide film 13 as a gate insulating film is formed by plasma CVD, low-pressure CVD, or sputtering. A gate line (gate electrode) 14 is then obtained by forming and a 5,000-Å-thick polysilicon film containing phosphorus by low-pressure CVD and etching it (see FIG. 3A ).
Subsequently, a source 15 and a drain 16 are formed by implanting, into the active layer 12 , ions of phosphorus that is an impurity for imparting n-type conductivity at a dose of 5×10 14 to 5×10 15 atoms/cm 2 . The source 15 and the drain 16 are given n-type conductivity. After the implantation of impurity ions, the impurity-ion-implanted regions are activated by performing a heat treatment or illumination with laser light or strong light.
Then, after a 5,000-Å-thick silicon oxide interlayer insulating film 17 is formed, contact holes reaching the source 15 and the drain 16 are formed by etching both the interlayer insulating film 17 and the gate insulating film 13 . Then, a source line 18 and a metal wiring (auxiliary capacitor electrode) 19 are formed by a known metal wiring forming technique (see FIG. 3B ).
FIG. 2A is a top view showing a circuit that has been formed by the above steps.
Thereafter, a silicon nitride film 20 is formed at a thickness of 250-1,000 Å (in this embodiment, 500 Å) by a plasma CVD method that uses silane and ammonia, silane and N 2 O, or silane, ammonia, and N 2 O. Alternatively, the silicon nitride film 20 may be formed by using dichlorosilane and ammonia. As a further alternative, it may be formed by low-pressure CVD, photo CVD, or other proper methods.
Subsequently, a polyimide layer 21 is formed by spin coating at a thickness of at least 8,000 Å, preferably 1.5 μm. The surface of the polyimide layer 21 is planarized. An interlayer insulating film consisting of the silicon nitride layer 20 and the polyimide layer 21 is thus formed. Then, an opening 22 for an auxiliary capacitor is formed by etching the polyimide layer 21 (see FIG. 3C ).
Depending on the etchant used, the silicon nitride layer 20 may also be etched in the step of etching the polyimide layer 21 . Therefore, to protect the silicon nitride film 20 , a silicon oxide film having a thickness of 50-500 Å, for instance, 200 Å, may be formed between the silicon nitride layer 20 and the polyimide layer 21 .
Then, a 1,000-Å-thick titanium film is formed by sputtering. It goes without saying that some other metal film such as a chromium film or an aluminum film may be formed, and that other proper film forming methods may be used. A black matrix 23 is formed by etching the titanium film so as to cover the opening 22 for an auxiliary capacitor (see FIG. 3D ).
FIG. 2B is a top view showing the opening 22 for an auxiliary capacitor and the black matrix 23 that have been formed by the above steps. An auxiliary capacitor is formed in the region where the opening 22 and the black matrix 23 overlap each other. A contact hole for a pixel electrode will be formed later in a contact region 31 where the metal wiring 19 and the black matrix 23 do not overlap.
Then, after a 5,000-Å-thick polyimide film 24 is formed as an interlayer insulating film, a contact hole reaching the metal electrode 19 is formed by etching the polyimide films 21 and 24 in the contact region 31 . A pixel electrode 25 is then formed by forming a 1,000-Å-thick ITO (indium tin oxide) film by sputtering and etching it (see FIG. 3E ).
An active matrix circuit is thus completed. An insulating film made of polyimide, like the one used in this embodiment, can easily be planarized and hence is very advantageous. In this embodiment, the auxiliary capacitor is formed in the region 22 where the black matrix 23 and the metal wiring 19 are in close proximity to each other. The silicon nitride layer 17 serves as a dielectric.
Embodiment 2
FIGS. 4A and 4B are top views showing a manufacturing processing according to this embodiment. The manufacturing process itself of this embodiment is almost the same as that of the first embodiment. The reference numerals commonly used in the first and second embodiments represent the same or equivalent parts. This embodiment is different from the first embodiment in circuit layout; that is, each pixel is formed efficiently (i.e., the effective aperture ratio is increased) by forming the auxiliary capacitor in a region where disclination is prone to occur.
FIG. 5 shows a pixel having the same circuit layout as the pixel according to the first embodiment. As shown in FIG. 5 , disclination is prone to occur in a top-right region 30 of the pixel in a display device in which a pixel electrode contact 31 is provided at a top-right position of the pixel, rubbing is performed in the top-right to bottom-left direction (not bottom-left to top-right direction), and the source-line-inverted driving is performed. (The source-line-inverted driving is a driving method in which signals of opposite polarities are applied to adjacent source lines, and includes the dot-inverted driving). Since the region 30 is not suitable for use for display, it is desired to cover it with a black matrix.
In view of the above, in this embodiment, a metal wiring 19 is provided in a right-hand region of the pixel as shown in FIG. 4A rather than in the top portion as in the case of the first embodiment.
Further, an opening 22 is formed in the metal wiring 19 and is covered with a black matrix 23 . It is effective to form a contact for a pixel electrode in a bottom-right region 31 as shown in FIG. 4B .
In this manner, the auxiliary capacitor is formed in the region where disclination is prone to occur. In this embodiment, the auxiliary capacitor that is provided in the top portion of the pixel in the circuit of the first embodiment is moved to the right-hand region and hence the area of the opening remains the same in terms of the circuit designing. However, the effective opening area can be increased by overlapping the disclination and the auxiliary capacitor (or BM) with each other.
Embodiment 3
FIGS. 6A and 6B are top views showing a manufacturing processing according to this embodiment. The manufacturing process itself of this embodiment is almost the same as that of the first embodiment. The reference numerals commonly used in the first and third embodiments represent the same or equivalent parts. Although the layout relating to the auxiliary capacitor in this embodiment is substantially the same as in the second embodiment, in this embodiment it is intended to utilize the available area of each pixel more efficiently by changing the layout relating to the active layer of the thin-film transistor.
In this embodiment, rubbing is performed in the bottom-left to top-right direction, in which case disclination is prone to occur in a bottom-left region. While in the second embodiment the auxiliary capacitor is provided in such a region where disclination is prone to occur, in this embodiment part of the active layer of the thin-film transistor of the next row is additionally formed in this region. That is, as shown in FIG. 6A , a metal wiring 19 is provided in a left-hand region of the pixel and an active layer 12 is formed so as to cross a gate line 14 that is straightened (i.e., the branch portion of the gate line is removed).
Further, an opening 22 is formed in a metal wiring 19 and is covered with a black matrix 23 (see FIG. 6B ).
In this manner, the auxiliary capacitor and part of the thin-film transistor are formed in the region where disclination is prone to occur. According to this embodiment, the available area of each pixel can be utilized more efficiently by a degree corresponding to the removal of the branch portion of the gate line.
Embodiment 4
FIGS. 7A and 7B are a top view and a circuit diagram of a thin-film transistor according to this embodiment, and FIGS. 8A and 8B are top views showing a manufacturing process according to this embodiment. The manufacturing process itself of this embodiment is almost the same as that of the first embodiment. The reference numerals commonly used in the first and fourth embodiments represent the same or equivalent parts, and the reference numerals used in FIGS. 7A-7B and 8 A- 8 B correspond to each other. Although the layout relating to the auxiliary capacitor in this embodiment is substantially the same as in the second embodiment, in this embodiment it is intended to utilize the available area of each pixel more efficiently by improving the characteristics of the thin-film transistor by changing the layout relating to the active layer of the thin-film transistor and the gate electrode.
In this embodiment, rubbing is performed in the bottom-left to top-right direction as in the case of the third embodiment and hence disclination is prone to occur in a bottom-left region. While in the second embodiment the auxiliary capacitor is provided in such a region and in the third embodiment the auxiliary capacitor and part of the active layer of a single-gate thin-film transistor are formed in this region, in this embodiment the active layer of a triple-gate thin-film transistor and the gate electrode are provided in this region as well as the auxiliary capacitor.
First, a triple-gate thin-film transistor used in this embodiment will be outlined with reference to FIG. 7A . This thin-film transistor is configured in such a manner that a gate line 14 is formed with a branch portion 29 and an active layer 12 overlaps with the gate line 14 and its branch portion 29 as shown in FIG. 7A . Transistors are formed at respective overlap portions 26 - 28 .
That is as shown in FIG. 7B , three thin-film transistors are formed in series between a source line 18 and a metal wiring 19 .
It is known that it is particularly effective to use this type of multiple transistor as a switching transistor of an active matrix (refer to Japanese Examined Patent Publication No. Hei. 5-44195).
Although the thin-film transistor having the above structure occupies a bottom-left region of the pixel of the next row, this does not reduce the aperture ratio as in the case of the second and third embodiments because this region is a region where disclination is prone to occur. That is, as shown in FIG. 8A , the gate line 14 is provided with the branch portion 29 and the active layer 12 is formed so as to cross the gate line 14 and its branch portion 29 three times in total. Further, a metal wiring 19 is formed in a left-hand region of the pixel as shown in FIG. 8A .
Further, an opening 22 is formed in the metal wiring 29 and is covered with a black matrix 23 (see FIG. 8B ).
In this manner, the auxiliary capacitor and part of the thin-film transistor are formed in the region where disclination is prone to occur. This embodiment is disadvantageous as compared to the third embodiment in that the gate line needs the branch portion as in the case of the circuit of the second embodiment, by virtue of the use of the triple-gate thin-film transistor the auxiliary capacitance may be far smaller than in the third embodiment. Therefore, on balance, this embodiment is superior to the third embodiment in terms of characteristics.
Embodiment 5
FIGS. 9A-9B and FIGS. 11A-11D are top views and sectional views, respectively, showing a manufacturing process according to this embodiment. The reference numerals used in FIGS. 9A-9B and FIGS. 11A-11D correspond to each other, and the reference numerals commonly used in this embodiment and the above embodiments represent the same or equivalent parts. The layout relating to the auxiliary capacitor in this embodiment is different from that in the pixel circuit having the laminate structure of the first embodiment.
As in the case of the first embodiment, a 500-Å-thick amorphous silicon film is formed, by plasma CVD or low-pressure CVD, on a glass substrate 11 on which a proper underlayer film is formed. Then, an active layer 12 of a thin-film transistor is obtained by converting the amorphous silicon film into a crystalline silicon film by a known annealing technique and etching the crystalline silicon film.
Then, a 1,000-Å-thick silicon oxide film 13 is formed as a gate insulating film. A gate line (gate electrode) 14 is then obtained by forming a 5,000-Å-thick polysilicon film containing phosphorus by low-pressure CVD and etching it (see FIG. 11A ).
Subsequently, a source 15 and a drain 16 are formed by implanting, into the active layer 12 , ions of phosphorus that is an impurity for imparting n-type conductivity at a dose of 5×10 14 to 5×10 15 atoms/cm 2 . Annealing is performed after the implantation of impurity ions.
Thereafter, a 2-μm-thick silicon oxide interlayer insulating film 17 is formed by a known insulating layer forming technique, and its surface is planarized by a known planarization technique (for instance, chemical mechanical polishing (CMP)). Then, contact holes reaching the source 15 and the drain 16 are formed by etching the interlayer insulating film 17 and the gate insulating film 13 . Then, a source line 18 and a metal wiring (auxiliary capacitor electrode) 19 are formed by a known metal wiring forming technique. At this time, the metal wiring 19 is formed so as to cover the gate line 14 (see FIG. 11B ).
FIG. 9A is a top view showing a circuit that has been formed by the above steps. This embodiment has a feature that the metal wiring 19 to serve as an electrode of the auxiliary capacitor partially covers the gate line 14 . Being light-interruptive, both of the gate line 14 and the metal wiring 19 are factors of reducing the area of the pixel region that is usable for display. In the first embodiment, they are arranged so as not to overlap with each other and hence the area of the pixel region that is usable for display is reduced accordingly. This embodiment enables a larger area of the pixel to be used for display because of the structure that the gate line 14 and the metal wiring 19 overlap with each other.
Where the gate line 14 for driving the pixel electrode concerned and the metal wiring 19 that is connected to the pixel electrode overlap with each other as shown in FIG. 9A , it is preferable to weaken the capacitance coupling between the gate line 14 and the metal wiring 19 . In this embodiment, this is done by making the interlayer insulating film 17 sufficiently thick. Alternatively, the metal wiring 19 may be overlapped with the gate line 14 of the next row.
Thereafter, a silicon nitride film 20 is formed at a thickness of 250-1,000 Å (in this embodiment, 500 Å). A 200-Å-thick silicon oxide film (not shown) is then deposited. Subsequently, a polyimide layer 21 is formed by spin coating at a thickness of at least 8,000 Å or more, preferably 1.5 μm. The surface of the polyimide layer 21 is planarized. An interlayer insulating film consisting of the silicon nitride layer 20 and the polyimide layer 21 is thus formed. Then, an opening 22 for an auxiliary capacitor is formed by etching the polyimide layer 21 (see FIG. 11C ).
Then, a 1,000-Å-thick titanium film is formed by sputtering. A black matrix 23 is formed so as to cover the opening 22 for an auxiliary capacitor by etching the titanium film.
FIG. 9B is a top view showing the opening 22 for an auxiliary capacitor and the black matrix 23 that have been formed by the above steps. An auxiliary capacitor is formed in the region where the opening 22 and the black matrix 23 overlap. To increase the area of the opening portion, it is preferable to form the opening 22 for an auxiliary capacitor so as to overlap with the gate line 14 . To form a contact hole for a pixel electrode, a region 31 where the metal wiring 19 and the black matrix 23 do not overlap is provided.
Then, after a 5,000-Å-thick polyimide film 24 is formed as an interlayer insulating film, a contact hole reaching the metal electrode 19 is formed by etching the portions of the polyimide films 21 and 24 in the region 31 . A pixel electrode 25 is then formed by forming a 1,000-Å-thick ITO (indium tin oxide) film by sputtering and etching it (see FIG. 11D ).
An active matrix circuit is thus completed. Although this embodiment is directed to the case of using the single-gate TFT, a similar pixel circuit may be obtained by using a multi-gate TFT, in which case the same advantages are obtained.
Embodiment 6
This embodiment will be described below with reference to FIGS. 12-15 . FIG. 12 shows active layers 105 - 108 that are formed in the lowest layer, i.e., on a glass substrate, a quartz substrate, or some other insulating surface.
A gate insulating film (not shown) is formed on the active layers 105 - 108 . Gate lines 101 and 102 are formed on the gate insulating film.
The portions of each of the active layers 105 - 108 where the gate line 101 or 102 crosses the active layer become channel forming regions.
An interlayer insulating film (not shown) is formed on the gate lines 101 and 102 , and source lines 103 and 104 are formed on the interlayer insulating film.
For example, the source line 104 is connected to the source region that is formed in the active layer 106 via a contact 109 .
Drain electrodes 109 - 112 are formed by using the same material as the source lines 103 and 104 are done (i.e., by patterning the same film as the source lines 103 and 104 are done).
The drain electrodes 109 - 112 will be used to form capacitors and constitute parts of a black matrix.
An extension 113 of the drain electrode 112 is a pattern to increase the capacitance.
Each of the drain electrodes 109 - 112 is shaped so as to cover half or more of the active layer. With this structure, a desired auxiliary capacitance can be obtained without a large reduction in aperture ratio.
FIG. 13 shows a state that after the state of FIG. 12 a silicon nitride film (not shown) has been formed and capacitor lines 1113 and 1114 have been formed thereon. The silicon nitride film serves as a dielectric of each auxiliary capacitor.
FIG. 14 shows a state that after the state of FIG. 13 an interlayer insulating film has been formed on the capacitor lines 1113 and 1114 and ITO pixel electrodes 115 - 123 have been formed on the interlayer insulating film.
In the configuration of this embodiment, the auxiliary capacitor is formed so as to cover the TFT and hence the aperture ratio of the pixel can be maximized.
Further, a large capacitance can be obtained by forming the capacitor between the capacitor line and the drain electrode that is formed between the drain region and the pixel electrode at the same time as the source line. This is because this configuration allows the dielectric film (in this embodiment, the silicon nitride film) that constitutes the auxiliary capacitor to be made thinner.
As described above, according to the invention, the conductive film used as a black matrix is used as an electrode and the auxiliary capacitor is formed between this conductive film and the metal wiring that is in the same layer as the source line.
With this configuration, the aperture ratio of the pixel can be increased because the top portion of the TFT is used to form a capacitor.
Although the embodiments are directed to the case of using the top-gate TFT, it is apparent that the invention can similarly be applied to the case of using the bottom-gate TFT because the invention is an improvement in the structure above the source line.
Having the above advantages, the invention is useful from the industrial viewpoint.
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A first insulating thin film having a large dielectric constant such as a silicon nitride film is formed so as to cover a source line and a metal wiring that is in the same layer as the source line. A second insulating film that is high in flatness is formed on the first insulating film. An opening is formed in the second insulating film by etching the second insulating film, to selectively expose the first insulating film. A conductive film to serve as a light-interruptive film is formed on the second insulating film and in the opening, whereby an auxiliary capacitor of the pixel is formed between the conductive film and the metal wiring with first the insulating film serving as a dielectric. The effective aperture ratio can be increased by forming the auxiliary capacitor in a selected region where the influences of alignment disorder of liquid crystal molecules, i.e., disclination, are large.
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BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a refractory article known in the art as an “impact pad” for use in handling molten metals, especially steel. The invention particularly relates to an impact pad for placement in a tundish for reducing turbulence in a flow of molten steel entering the tundish. The present invention finds particular utility in the continuous casting of steel.
(2) Description of the Related Art
Tundishes act as holding tanks for said molten metal, and especially for molten steel in commercial processes for the continuous casting of steel. In the continuous casting of steel, the molten steel fed to the tundish is generally high-grade steel that has been subjected to various steps for rendering it suitable for the particular casting application. Such steps normally involve, for example, one or more steps to control the levels of the various elements present in the steel, for example the level of carbon or other alloying ingredients, and the level of contaminants such as slag. The residence of the steel in the tundish provides a further opportunity for any entrained slag and other impurities to segregate and float to the surface where they can be, for example, absorbed into a special protective layer provided on the surface of the molten steel. Thus the tundish can be used to further “clean” the steel before it is fed to the mould for casting.
To optimize the ability of the tundish to continuously furnish a supply of clean steel to the mould, it is highly desirable to control and streamline the flow of steel through the tundish. Molten steel is normally fed to the tundish from a ladle via a shroud that protects the stream of steel from the surrounding atmosphere. The stream of molten steel from the ladle generally enters the tundish with considerable force, and this can generate considerable turbulence within the tundish itself. Any undue turbulence in the flow of molten steel through the tundish has a number of undesirable effects including, for example; preventing slag and other undesirable inclusions in the steel from agglomerating and floating to the surface; entraining into the molten steel a part of the protective crust that forms, or is specifically provided, on the surface of thereof; entraining gas into the molten steel; causing undue erosion of the refractory lining within the tundish; and generating an uneven flow of the molten steel to the casting mould.
In an effort to overcome these problems the industry has undertaken extensive research into various designs of impact pads for reducing turbulence in the tundish arising from the incoming stream of molten steel, and for optimizing the flow within the tundish to approximate ideal “plug flow” characteristics as nearly as possible of the molten steel as it traverses the tundish. Generally speaking it has been found that the flow of molten steel through the tundish can often be improved using impact pads that have specially designed surfaces capable of redirecting and streamlining the flow of molten steel.
Plug flow behavior (i.e., passage of successive portions of steel through the tundish without significant mixing) requires direction of flow away from the tundish outlet after the molten steel recedes from the impact pad. The presence of a significant portion of flow from the impact pad to the tundish outlet, with a minimized residence time in the tundish, is known as “short-circuiting.” Impact pads disclosed in the prior art have generally been designed with particular attention to the upwardly directed component of the resulting flow. An increase in the residence time, and an increase in the uniformity of residence time, in the tundish corresponds to the minimization of mixing, and enables successive steel formulations to pass through the tundish with retention of their respective compositions.
Impact pads disclosed in the prior art generally comprise a base against which a downwardly directed stream of molten steel impinges, and a vertical sidewall or sidewall elements that redirect the stream. They are fabricated from refractory materials capable of withstanding the corrosive and erosive effects of a stream of molten steel for their working lives. They are frequently shaped in the form of shallow boxes having, for example, square, rectangular, trapezoidal or circular bases.
It will be appreciated that the process of designing a new tundish impact pad which meets particular pre-determined criteria is extremely complex, since changing one aspect of the design of an impact pad generally has unforeseen ramifications on the flow dynamics of the entire tundish system.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved impact pad suitable for placement in a tundish for increasing the residence time, inducing uniformity of residence time, and minimizing short-circuiting, of the flow of molten metal introduced therein.
The present invention provides a tundish impact pad formed from refractory material comprising a base having an impact surface which, in use, faces upwardly against a stream of molten metal entering a tundish, a wall extending upwardly from the base around at least a part of the periphery of the impact surface having a latitudinal portion, a longitudinal portion in certain embodiments, and an inwardly extending feature protruding from the latitudinal portion of the wall. In certain embodiments of the invention, the inwardly extending feature may take the form of a protrusion, which may have a width less than the extent of the latitudinal portion of the wall. In embodiments in which the protrusion has a width less than the extent of the latitudinal portion of the wall, and in the presence of a longitudinal portion of the wall, a flow channel is formed between the longitudinal portion of the wall and an adjacent portion of the surface of the protrusion.
The present invention may also be described as a tundish impact pad formed from refractory material comprising a base having an impact surface which, in use, faces upwardly against a stream of molten metal entering a tundish, and a wall extending upwardly from the base around at least a part of the periphery of the impact surface, the base and the wall defining an interior, the pad having a longitudinal central minimum extent, the wall having a longitudinal portion having an interior, an internal extent and an internal length, and a latitudinal portion having an interior, an internal extent and an internal length, wherein the internal extent of the longitudinal portion of the wall is greater than the longitudinal central minimum extent of the pad, and wherein the internal length of the latitudinal portion of the wall is greater than the internal extent of the latitudinal portion of the wall. The internal extent of a wall is the straight-line measurement from one end of the interior of a wall to the other; the internal length of a wall is the distance along the interior surface of the wall from one end of the wall to the other
The present invention may also be described as a tundish impact pad having a base and a latitudinal wall extending upwardly from the base. The impact pad is distinguished by producing, in use, flow velocities of fluid across the top of the latitudinal wall that exhibit a minimum at a central portion of the latitudinal portion of the wall in the absence of any variation in wall height.
The wall may extend partially around the periphery of the base, or may extend around the entire periphery of the base. In certain embodiments wherein the wall extends around the entire periphery of the base, the wall has a uniform height. The wall may be vertical or have an angle in the range from, and including, 1 degree to, and including, 30 degrees from the vertical.
One or more portions of the upper part of the wall may support one or more overhangs which project inwardly over the periphery of the base.
The protrusion may take the form of a shoulder, whereby the protrusion may protrude form a longitudinal portion of the wall as well as from a latitudinal portion of the wall.
The protrusion may be configured and arranged in various ways. The protrusion may be centered on the latitudinal wall, or may be disposed off-center on the latitudinal wall. In one embodiment, the interior surface of the protrusion intersects the interior of the latitudinal portion of the wall at an angle greater than 90 degrees. The interior surface of the protrusion may be composed entirely of planar surfaces, may contain at least one quadrilateral surface, may contain one or more rectangular surfaces, may be composed entirely of rectangular surfaces, may have the form of a radial surface of a cylinder, or may have a parabolic horizontal section. The ratio of the width of the protrusion to the height of the protrusion may be 1 or greater, may have a value in the range from, and including 0.8 to, and including, 1.5, or may have a value in the range from, and including 0.8 to, and including, 2. The ratio of the width of the protrusion to the internal extent of the latitudinal wall of the impact pad may be in the range from, and including, 0.1 to, and including, 1. The ratio of the extent of the protrusion to the width of the protrusion may be in the range from, and including 0.3 to, and including, 3. The interior surface of the protrusion may be vertical, or may have an angle from the vertical in the range of, and including 1 degree to, and including, 30 degrees. The height of the protrusion may equal the height of the portion of the latitudinal portion of the wall with which it is in contact, or may have a height ratio to the latitudinal wall portion in the range from, and including, 0.3 to, and including, 1.
The interior surface of a protrusion and the interior surface of a longitudinal portion of the wall may converge to form a flow channel having a floor, and having an end distal to the center of the impact pad. The distal end of the flow channel may be partially blocked; flow in the horizontal direction may be partially or fully obstructed and an overhang may partially obstruct flow in the vertical direction. The interior surface of the protrusion and the interior surface of the longitudinal portion of the wall may or may not intersect. The angle formed by the interior surface of the protrusion and the interior surface of the longitudinal portion of the wall may decrease towards the distal end of the flow channel. The decrease in angle may be continuous or incremental. The floor of the flow channel may increase in elevation as it extends towards the distal end of the flow channel. The floor of the flow channel may form an angle less than 180 degrees with the impact surface of the impact pad; this angle may be in the range from, and including, 110 degrees to, and including, 160 degrees, may be in the range from, and including, 115 degrees to, and including, 155 degrees, may be in the range from, and including, 120 degrees to, and including, 150 degrees, or may have values of 115, 120, 125, 127, 130, 135, 140, 145, 150 or 155 degrees.
The base of the impact pad can be of any suitable shape, for example, polyhedral shapes such as, for example, square, rectangular, trapezoidal, rhomboidal, hexagonal, octagonal, circular or elliptical.
The impact surface of the base is adapted to receive the main force of the flow of metal entering the tundish. It can be, for example, planar, concave or convex. The base itself can, if desired, be affixed to the base of a tundish using any suitable means, for example, using refractory cement, or by locating the base by means of corresponding elements formed in the surface of the refractory lining of the tundish and the underside of the impact pad. The impact pad may be embedded into the refractory base of the tundish. This can be achieved, for example, by placing the impact pad on the monolithic refractory lining of a tundish, placing a layer of cold cure or hot cure refractory power composition to surround the base and optionally part of the outer wall of the impact pad, and then curing the refractories to bind the impact pad in position in the tundish.
The wall extending upwardly from the base around at least a part of the periphery of the impact surface may be made from the same material as the base and may be integral therewith. At least one wall extending upwardly from the base around at least a part of the periphery of the impact surface may have a mirror image counterpart wall extending upwardly from the opposite peripheral part of the base.
In the case that the impact pad is intended for so-called “two strand” operation, the wall may extend around the entire periphery of the base. The wall may extend substantially perpendicular in relation to the base. Thus, a linear peripheral portion of the base may support a vertical planar wall portion, whereas a curved portion of the base may support a vertical wall having correspondingly curved horizontal cross section.
In the case that the impact pad has a rectangular or trapezoidal-shaped base and is intended for so called “single strand” operation, the wall may extend around three sides of the base, with the fourth side having either no wall, or a relatively low wall. The impact pad may be configured so that it has a single inwardly extending feature; in use, the impact pad may be installed in the tundish so that the inwardly extending feature is oriented adjacent to the tundish outlet.
One or more portions of the upper part of the wall may support one or more overhangs which project inwardly over the periphery of the base. The overhang may be in the form of an inner peripheral strip projecting inwardly from the wall. The peripheral strip may project from the top of the wall.
In the case that the impact pad is designed primarily for double strand operation, the overhang, e.g. a peripheral strip, may be omitted, may run along at least 50%, at least 75% or along 100% of the length of the wall. In the case that the impact pad is designed primarily for single strand operation, the overhang, e.g. a peripheral strip, may be omitted, may run along 50% to 100%, or 60 to 80% of the length of the wall.
An impact pad for single strand operation may have a single protrusion that will be located adjacent to the single tundish outlet. This configuration may have one flow channel or two flow channels located adjacent to the single tundish outlet. For two strand operation, an impact pad may have one or more flow channels located adjacent to each of the tundish outlets, i.e., on opposite latitudinal walls.
The upper surfaces of the overhang may be smooth surfaces. The upper surface can have a profile matching the profile of the under-surface if desired, e.g. to provide an overhang having a substantially uniform thickness at least in the portion occupied by the curved or sloping portion.
The junction between the wall and the impact surface (i.e. the upper surface of the base) can take the form of a sharp angle, e.g. a right angle, or an acute angle or an obtuse angle, or can be rounded or curved.
The impact pad according to the present invention can be made using the standard molding techniques well known in the art for forming refractory shaped articles. The impact pad can, if desired, be fabricated in two or more separate parts which can then be joined together to form the final article, or can be fabricated as a monolithic structure (i.e., formed in one piece as a single integral article).
The refractory material from which the impact pad is fabricated can be any suitable refractory material capable of withstanding the erosive and corrosive effects of a stream of molten metal throughout its working life. Examples of suitable materials are refractory concretes, for example concretes based on one or more particulate refractories, and one or more suitable binders. Refractories suitable for the manufacture of impact pads are well known in the art, for example alumina, magnesia and compounds or composites thereof. Similarly suitable binders are well known in the art, for example, high alumina cement.
Impact pads in accordance with the present invention can be made for use with tundishes operating in single strand, two strand or multi strand mode. As is well known in the art, continuous casting steel processes operating in single strand and multi strand (delta tundish) modes generally employ impact pads having square, rectangular or trapezoidal cross section (in the horizontal plane) wherein one pair of opposite sides are provided with walls having equal height, a third side also having a wall, and the fourth side either having a lower wall or no wall. In the double (or sometime quadruple or six-fold) strand technologies, the impact pads generally have square or rectangular cross section wherein a first pair of opposite sides are provided with walls having equal height, and the second pair of opposite sides are also of equal height (which may be the same as, or different from the height of the first pair). In single strand and multiple strand operation the impact pad is generally positioned near one end of the tundish to one side of the area wherein the outlet(s) for the molten steel are situated, whereas in double strand operation the impact pad is generally positioned in the center of a rectangular tundish with two outlets situated on opposite sides of the impact pad (or in quadruple strand operation, two pairs of outlets situated on opposite sides, or in six-fold strand operation, three pairs of outlets situated on opposite sides).
Impact pads in accordance with the present invention can be used, for example, to provide reduced dead volume and/or improved plug flow and/or reduced turbulence in tundishes for holding molten steel.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
The invention will now be described with reference to the accompanying drawings wherein:
FIG. 1 is a perspective view of an impact pad of the present invention;
FIG. 2 is a plan view of an impact pad of the present invention;
FIG. 3 is a perspective drawing of an impact pad of the present invention;
FIG. 4 is a plan view of an impact pad of the present invention;
FIG. 5 is a cross section view of an impact pad of the present invention;
FIG. 6 is a plan view of the interior of the wall of an impact pad of the present invention;
FIG. 7 is a plan view of the interior of the wall of an impact pad of the present invention;
FIG. 8 is a plan view of the interior of the wall of an impact pad of the present invention;
FIG. 9 is a plot of flow velocities of molten metal flowing over a latitudinal wall of an impact pad of the present invention plotted as a function of distance along the latitudinal wall;
FIG. 10 is a perspective view of an impact pad of the prior art;
FIG. 11 is a plan view of a multi-strand tundish containing an impact pad;
FIG. 12 is a plot of flow volumes exiting a tundish as a function of time in a tundish containing an impact pad of the prior art; and
FIG. 13 is a plot of flow volumes exiting a tundish as a function of time in a tundish containing an impact pad of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an impact pad 10 comprising a base 20 having an impact surface 21 facing upwards towards an interior, and a wall 22 extending upwardly from base 20 . The wall 22 has a longitudinal portion 24 and a latitudinal portion 26 . A protrusion 30 extends inwardly, towards the center of the impact pad, from latitudinal portion 26 . Protrusion height 32 is the distance between the impact pad impact surface 21 and the top of protrusion 30 . Overhang 34 extends horizontally inwards from the top of wall 22 .
FIG. 2 shows a plan view of an impact pad 10 of the present invention. Base 20 has an impact surface 21 ; wall 22 extends from the impact surface 21 . Wall 22 is composed of longitudinal portions 24 and latitudinal portions 26 . A pair of protrusions 30 extends inwardly, towards the center of the impact pad, each from latitudinal portions 26 . Overhang 34 extends horizontally inwards from the top of wall 22 . The interior of the latitudinal portion 26 has an extent 40 indicating the straight-line distance between the endpoints of the latitudinal portion. Protrusion width 44 indicates the straight-line distance between two intersections of the protrusion 30 with latitudinal wall portion 26 . Protrusion extent 46 indicates the longitudinal distance between an intersection of the protrusion 30 with latitudinal wall portion 26 and the point on protrusion 30 furthest from latitudinal wall portion 26 , inclusive of any portion of overhang 34 in direct contact with protrusion 26 . Flow channel 50 is formed within an angle 52 produced by the convergence of the interior of a longitudinal portion 24 and protrusion 30 . In this embodiment of the invention, successive segments of the protrusion 30 form successively smaller angles with the interior of longitudinal portion 24 as longitudinal portion 24 and protrusion 30 converge. In this embodiment of the invention, longitudinal portion 24 and protrusion 30 do not intersect; instead, longitudinal portion 24 and protrusion 30 each intersect an interior surface of latitudinal portion 26 of impact pad wall 22 . The angle 53 is the angle of intersection of the interior surface of the protrusion with the interior of the latitudinal portion 26 of the wall; in the embodiment shown, the angle is greater than 90 degrees.
FIG. 3 shows an impact pad 10 comprising a base 20 having an impact surface 21 facing upwards towards an interior, and a wall 22 extending upwardly from base 20 . The wall 22 has a longitudinal portion 24 and a latitudinal portion 26 . A protrusion 30 extends inwardly, towards the center of the impact pad, from latitudinal portion 26 . Protrusion height 32 is the distance between the impact pad impact surface 21 and the top of protrusion 30 . Overhang 34 extends horizontally inwards from the top of wall 22 . Flow channel 50 is formed within an angle produced by the convergence of the interior of a longitudinal portion 24 and protrusion 30 , and is partially closed at an end distal to the center of the interior of the impact pad. Flow riser 54 , located within a flow channel, is a portion of the floor of flow channel 50 that increases in elevation as it extends towards the partially closed end of the flow channel.
FIG. 4 provides a plan view of embodiment of the invention with flow risers. Base 20 has an impact surface 21 ; wall 22 extends upwardly from the impact surface 21 . Wall 22 is composed of longitudinal portions 24 and latitudinal portions 26 . A pair of protrusions 30 extends inwardly, towards the center of the impact pad, each from latitudinal portions 26 . Overhang 34 extends horizontally inwards from the top of wall 22 . Flow channel 50 is formed within an angle produced by the convergence of the interior of a longitudinal portion 24 and protrusion 30 . In this embodiment of the invention, successive segments of the protrusion 30 form successively smaller angles with the interior of longitudinal portion 24 as longitudinal portion 24 and protrusion 30 converge. In this embodiment of the invention, longitudinal portion 24 and protrusion 30 do not intersect; instead, longitudinal portion 24 and protrusion 30 each intersect an interior surface of latitudinal portion 26 of impact pad wall 22 . Flow channel 50 is partially closed at an end distal to the center of the interior of the impact pad. Flow riser 54 , located within a flow channel, is a portion of the floor of flow channel 50 that increases in elevation as it extends towards the partially closed end of the flow channel.
FIG. 5 represents a cross section, along section line AA in FIG. 4 , of an impact pad 10 of the present invention, containing base 20 , on which impact surface 21 is located. Latitudinal wall portion 26 is a portion of a wall extending upwardly from base 20 . Flow channel 50 is in communication with the interior of impact pad 10 . A portion of the floor of flow channel 50 describes an angle with impact surface 21 . This angle 56 is within the range of 90 to 180 degrees, may be within the ranges of 110 degrees to 160 degrees, 120 degrees to 150 degrees, and may have, for example, a value of 115, 120, 125, 127, 130, 135, 140, 145, 150 or 155 degrees.
FIG. 6 shows a plan view of the interior 60 of the wall of an impact pad of the present invention. Certain embodiments of the present invention are distinguished by having a central longitudinal minimum dimension 62 , measured between opposite protrusions 30 or between a protrusion 30 and a protrusionless latitudinal portion 26 , so that the longitudinal minimum dimension 62 is less than the interior longitudinal extent 42 of impact pad wall 22 . Certain embodiments of the present invention are also distinguished by having a central latitudinal dimension 64 , measured between opposite longitudinal wall portions 24 , and a protrusion 30 having a protrusion surface length 66 measured along the surface of the protrusion from two intersections of the protrusion with latitudinal wall portion 26 , so that central latitudinal dimension 64 is less than protrusion surface length 66 . In the embodiment shown in this figure, the inwardly-facing surface of protrusion 30 is composed of a series of adjoining rectangular planar surfaces.
FIG. 7 shows a plan view of the interior 60 of the wall of an impact pad of the present invention. Certain embodiments of the present invention are distinguished by having a central longitudinal minimum dimension 62 , measured between opposite protrusions 30 or between a protrusion 30 and a protrusionless latitudinal portion 26 , so that the longitudinal minimum dimension 62 is less than the interior longitudinal extent 42 of impact pad wall 22 . Certain embodiments of the present invention are also distinguished by having a central latitudinal dimension 64 , measured between opposite longitudinal wall portions 24 , and a protrusion 30 having a protrusion surface length 66 measured along the surface of the protrusion from two intersections of the protrusion with latitudinal wall portion 26 , so that central latitudinal dimension 64 is less than protrusion surface length 66 . In the embodiment shown in this figure, the inwardly-facing surface of protrusion 30 is in the form of a portion of the radial surface of a cylinder. In the embodiment shown in this figure, the convergence of the interior of a longitudinal portion 24 and protrusion 30 leads to the intersection of longitudinal portion 24 with a latitudinal wall portion 26 and the intersection of protrusion 30 with a latitudinal wall portion 26 , at which points the interior surfaces of longitudinal portion 24 and protrusion 30 are parallel.
FIG. 8 shows a plan view of the interior 60 of the wall of an impact pad of the present invention. In the embodiment depicted, both the longitudinal portions 24 and the latitudinal portions 26 of the wall have protrusions. Interior longitudinal extent 42 of the wall is greater than the central longitudinal minimum dimension 62 .
FIG. 9 depicts the flow velocity 80 plotted against latitudinal distance 84 over a latitudinal portion of the wall of an impact pad depicted in FIGS. 1 and 2 . Above the flow channels, flow velocity is increased. Above the protrusion, the flow velocity is decreased. The pattern of flow exhibits maxima 86 above the flow channels and a local minimum 88 above the protrusion.
FIG. 10 is a perspective view of impact pad 110 of prior art. The pad contains a base 112 with an impact surface 114 facing upwardly and facing the interior of the impact pad. A wall extends upwardly around the periphery of the base. The prior art impact pad contains no protrusion from a latitudinal wall, and no flow channel according to the definition of those terms as used to describe the present invention.
FIG. 11 is a plan representation of a casting tundish 120 . Impact pad 130 is placed in the tundish; molten metal flow into the tundish is arranged so that molten metal flows into impact pad 130 . Molten metal flows from the tundish into pairs of casting strands. Outlets for casting strands 132 are closest to the impact pad 130 ; outlets for casting strands 134 are at an intermediate distance from the impact pad 130 ; outlets for casting strands 136 are at the farthest distance from the impact pad 130 .
FIG. 12 depicts the performance of impact pad 110 of prior art. A model of a multi-strand tundish according to FIG. 11 was constructed so that flow of water containing tracer dye could be used to study flow patterns. In the experiment reported in FIG. 12 , a model of a prior art impact pad according to FIG. 10 was introduced, and the tundish model was filled with water containing no die. At time zero a pulse of tracer dye was injected into the inlet flow of water. This flow impacted the pad and dispersed throughout the tundish. As the water/dye mix simultaneously exited the tundish model through six different outlets a transmittance value was recorded 1 at three locations, each location corresponding to one of the outlets of the outlet pairs depicted in FIG. 11 . Plot 150 indicates values for light transmitted through a mixture of water and tracer dye. On plot 150 a transmittance value of zero indicates water containing no dye. Higher transmittance values indicate higher quantities of dye in the mix. The ordinate or vertical axis in plot 150 represents the transmittance values observed. The abscissa or horizontal axis in plot 150 represents time, in seconds, from the introduction of tracer dye to the system.
Results of the analysis are shown in graph 150 . The sensor at position 132 , producing results indicated by plot 152 , was located 2.16 inches from the exterior of the latitudinal wall of the impact pad. The sensor at position 134 , producing results indicated by plot 154 was located 16.16 inches from the exterior of the latitudinal wall of the impact pad. The sensor at position 136 , producing results indicated by plot 156 , was located 30.16 inches from the exterior of the latitudinal wall of the impact pad.
With prior art impact pad 110 there is a wide deviation in values among the three plots at a given time. Also, minimum residence time (MRT), as indicated by the time when the plot begins to rise, is a very short at location 132 and long at location 136 .
FIG. 13 depicts the performance of an impact pad 10 of the present invention, containing two protrusions, four flow channels, and a flow riser in each of the flow channels. A model of a multi-strand tundish according to FIG. 11 was constructed so that flow of water containing tracer dye could be used to study flow patterns. In the experiment reported in FIG. 13 , a model of an impact pad 10 according to FIG. 1 was introduced, and the tundish model was filled with water containing no die. At time zero a pulse of tracer dye was injected into the inlet flow of water. This flow impacted the pad and dispersed throughout the tundish. As the water/dye mix simultaneously exited the tundish model through six different outlets a transmittance value was recorded at three locations, each location corresponding to one of the outlets of the outlet pairs depicted in FIG. 11 . Plot 160 indicates values for light transmitted through a mixture of water and tracer dye. On plot 160 a transmittance value of zero indicates water containing no dye. Higher transmittance values indicate higher quantities of dye in the mix. The ordinate or vertical axis in plot 160 represents the transmittance values observed. The abscissa or horizontal axis in plot 160 represents time, in seconds, from the introduction of tracer dye to the system.
Results of the analysis are shown in graph 160 . The sensor at position 132 , producing results indicated by plot 162 , was located 2.16 inches from the exterior of the latitudinal wall of the impact pad. The sensor at position 134 , producing results indicated by plot 164 , was located 16.16 inches from the exterior of the latitudinal wall of the impact pad. The sensor at position 136 , producing results indicated by plot 166 , was located 30.16 inches from the exterior of the latitudinal wall of the impact pad.
The impact pad used to produce the results depicted in graph 160 directs the flow in such a way that the deviation in values among the three plots was significantly narrower at a given time than was observed for the prior art impact pad. For the present invention, MRT at location 132 was substantially increased while at the same time MRT at location 136 was reduced. This effect yields a greatly improved uniformity of water/dye concentration throughout the tundish model. For industrial applications, uniformity in MRT enables a more rapid changeover from one grade of steel to another in a multi-strand tundish.
Numerous modifications and variations of the present invention are possible. It is, therefore, to be understood that within the scope of the following claims, the invention may be practiced otherwise than as specifically described.
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A tundish impact pad formed from refractory material comprises a base having an impact surface which, in use, faces upwardly against a stream of molten metal entering a tundish, and a wall extending upwardly from the base around at least a part of the periphery of the impact surface. The wall has at least one latitudinal portion. An inwardly-extending feature protrudes from the latitudinal wall. The inwardly-extending feature inhibits flow exiting the impact pad from passing over the center of the latitudinal portion of the wall.
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RELATED APPLICATIONS
This application is a Continuation of PCT application serial number PCT/IB2003/004371 filed on Oct. 3, 2003 which claims the benefit of Provisional application Ser. No. 60/415,854 filed on Oct. 3, 2002 both of which are incorporated herein by reference in their entirety.
FIELD OF THE INVENTION
The present invention relates to an electrochemical capacitor having at least one chemically modified electrode based on a redox polymer of the poly-[Me(R-Salen) type. The invention also relates to a method of use of such a capacitor that provides for the restoring of electrochemical characteristics of the capacitor's electrodes.
BACKGROUND OF THE INVENTION
Capacitors with electrodes chemically modified by, for example, the immobilization of conducting polymers on the surface of inert electrodes are one of the promising types of electrochemical capacitors.
Conducting polymers are divided into two types [B. E. Conway, Electrochemical Supercapacitors//Kluwer Acad. Plen. Publ., NY, 1999, 698 p].
The so-called “organic metals” or conducting polymers—the polymers with the type of conductivity which is similar to the mechanism of conductivity of metals;
Redox polymers—the compounds in which the transfer of electrons occurs mainly due to the oxidation-reduction chemical reactions between the adjacent fragments of a polymer chain.
Examples of the “organic metals” are polyacetylene, polypyrrole, polytiophen, polyaniline. In a partially oxidized form, these polymers exhibit even higher conductivity and can be regarded as a salt consisting of positively charged “ions” of the polymer and counter-ions that are uniformly distributed throughout its structure and that support the overall electrical neutrality of the system. In solid state physics a cation-radical partially delocalized by polymer fragment is called a polaron. A polaron stabilizes, thus, polarizing the ambient medium. The polaron theory of conductivity is accepted as the main model of charge transfer in conducting polymers [Charge Transfer in Polymeric Systems//Faraday Discussions of the Chemical Society. 1989. V.88].
“Organic metals” may be produced by electrochemical oxidation of the appropriate monomers on the surface of the inert electrode. These polymers may be converted from the conducting (oxidized) state to the non-conducting (reduced) state via the variation of the electrode potential. The transfer of the polymer from the oxidized state to the neutral reduced state is accompanied by the departure of the charge-compensating counter-ions from the polymer to the electrolyte solution in which the process takes place, and vice versa.
The redox polymers comprise both purely organic systems and polymer metal complexes or metal organic compounds [H. G. Cassidy and K. A. Kun. Oxidation Reduction Polymer//Redox Polymers. Wiley—Interscience, New York, 1965]. The metal-containing polymers exhibit the highest conductivity.
As a rule, polymer metal complex compounds are obtained via electrochemical polymerization of the source monomer complex compounds, which have an octahedral configuration, the polymerization occurring on inert electrodes. The spatial configuration of the monomers plays a principle role in the formation of the polymer structures suitable for application in the capacitors. As an example of the redox polymers obtained from the octahedral source complex compounds, it is possible to consider polypyridine complexes of composition poly-[Me(v-bpy) x (L) y ], where.
Me=Co, Fe, Ru, Os;
v-bpy=4-vinyl-4′-methyl-2,2′-bipyridine;
L=v-bpy (4-vinyl-4′-methyl-2,2′-bipyridine), phenanthroline-5,6-dione, 4-methylphenanthroline, 5-aminophenanthroline, 5-chlorphenanthroline;
at that (x+y=3) [Hurrel H. C., Abruna H. D. Redox Conduction in Electropolymerized Films of Transition Metal Complexes of Os, Ru, Fe, and Co/Inorganic Chemistry. 1990. V.29 P.736–741].
Ions of metal, which may be in different charge states, serve as redox centers, i.e. atoms, which participate in the oxidation-reduction reactions in a polymer. Thus, complexes of metals having only one possible charge state (for example, zinc, cadmium) don't create redox polymers. The presence of the complexes of branched system of conjugated p-bonds bonds serve as conducting “bridges” between redox centers in the ligand environment is a necessary condition of conductivity of redox polymers. When a redox polymer is completely oxidized or completely reduced, i.e. when all its redox centers are in one charge state, the transfer of the charge along the polymer chain is impossible and the conductivity of the redox polymer is close to zero. When the redox centers have different charge states, the exchange of electrons between them becomes possible in the same manner as it happens in the solutions during the oxidation-reduction reactions. Therefore, the electric conductivity of redox polymers is proportional to the constant of the electron self-exchange rate between redox centers (k co ) and to the concentrations of oxidized and reduced centers ([Ox] and [Red]) in a polymer, i.e. the conductivity of a redox polymer is ˜k co [Ox) [Red].
The conductivity of redox polymers is maximumal at equal concentrations of oxidized and reduced redox centers, which corresponds to the conditions when a redox system has a standard oxidation-reduction potential equal to E° ([Ox]/[Red]).
The existence of the redox centers in different charge states was the reason for naming the redox polymers based on coordination compounds “Mixed valence complexes” or “partly oxidized complexes”. The transfer of redox polymer molecules from the oxidized state to the reduced state is accompanied (like it was described above in reference to conducting polymers) by the transition of charge-compensating counter-ions from the polymer into the electrolyte solution where the process takes place, and vice versa.
Compared to the electrodes modified by “organic metals” (conducting polymers), redox polymers and electrodes with redox polymers on their surface can potentially offer higher specific energy capacity due to a higher contribution of the Faraday component of the capacitance (related to the possibility of multi-electron oxidation/reduction of metal centers) to the overall capacitance of the polymer.
One of the disadvantages of electrochemical capacitors with chemically modified electrodes based on the redox polymer of a poly-[Me(R-Salen)] type is the deterioration of the electrochemical characteristics of their electrodes and the corresponding impairment of electric characteristics of the capacitors. This occurs due to a partial dissolution of a redox polymer in the electrolyte during operation of such a capacitor.
SUMMARY OF THE INVENTION
It is an object of the present invention to create a capacitor having specific features that make it possible to restore its electric characteristics. It is also an object of the present invention to provide a method of using such a capacitor enabling to regenerate a capacitor during operation.
An electrode based on the redox polymer of a poly-[Me(R-Salen) type comprises a conducting substrate, a layer of the energy-accumulating redox polymer produced by electrochemical polymerization or any other method and disposed on the conducting substrate. A polymer complex produced from complex compounds of transition metals (e.g. Ni, Pd; Co, Cu., and Fe) with at least two different oxidation levels is used as a redox polymer. Source complex compounds should be of a planar structure (with a deviation from a plane of no greater than 0.1 nm) and should have a branched system of π-bonds. Polymer metal complexes based on substituted tetra-dentate Schiffs bases, including poly-[Me(R-Salen)] (where: Me—transition metal, Salen—residue of bis(salicylaldehyde)-ethylenediamine in Schiff s base, R—electron-donating substituent: e.g. radicals CH 3 O—, C 2 H 5 O—, HO—, —CH 3 and others), comply with these requirements. The thickness of a polymer layer applied onto said substrate varies from 1 nm to 20 mm.
A structure that offers a high value of a specific surface parameter made of an electronically conductive material and which is electrochemically inactive within the range of potentials from about −3.0 to +1.5 V (from here on the potentials are given in relation to a reference chlorine-silver electrode) may be employed as a conducting substrate of the electrode. For example, it is possible to use carbon fiber and other carbon materials, carbon materials with metal coatings, and metal electrodes offering a high value of the specific surface parameter. Besides, electronically conductive polymers in the form of films, porous structures, foams and so forth may be used as a conducting substrate.
An electrolyte for the capacitor is prepared based on organic solvents—for example, acetonitrile, dimethyl ketone, propylene carbonate or others. It is also possible to use different mixtures of the above-indicated solvents and other solvents. To prepare an electrolyte, one should add certain substances to the solvents indicated above. Such substances should be capable of dissolving in said solvents with the resulting concentration of no less than 0.01 mol/l and of dissociating with the formation of ions that are electrochemically inactive within the range of potentials from −3.0 V to +1.5 V. Among such substances are, for example, salts of tetraethyl ammonium or tetramethyl ammonium—perchlorates, tetrafluoroborates, hexafluorophosphates and other substances meeting the above-indicated requirements.
A distinctive peculiarity of the capacitor claimed herein is that in addition to the solvent and electrochemically inactive ions, the electrolyte of the capacitor contains molecules of the source metal complex [Me(R-Salen)] forming the redox polymer layer on the electrode substrate; or molecules of a metal complex that is similar to this source metal complex and that meets the above-mentioned requirements to the source compounds used for the production of the energy-accumulating polymers.
The concentration of the metal complex solution may be from 5·10 −5 mol/liter to a value capped by solubility limit.
The electrolyte may also contain a mixture of different metal complexes that comply with the above-indicated requirements to the source compounds for the production of energy-accumulating polymers—for example, complexes of a [Me(R-Salen)] type containing different metal centers and/or different substituents of R in the ligand environment.
Due to the above-indicated specific features of the capacitor of the present invention, if the positive electrode of said capacitor is made on the basis of the abovementioned redox polymer, it is regenerated (i.e. it restores its electrochemical characteristics) while the capacitor is in use.
Addition of a metal complex to the electrolyte results in a considerable increase of the amount of energy stored by the positive electrode. This increase is caused by different chemical processes, in particular, healing of defects in the volume of the redox polymer layer of the positive electrode during the electrode charging and, partially, by the additional polymerization of the complex on the positive electrode surface.
The molecules of the metal complex diffuse into the redox polymer layer during the breaks between the charging and discharging cycles. When a voltage is supplied to the electrodes during the charging step, these complexes may integrate into the structure of the redox polymer. Thus, the restoration of the electrochemical characteristics of the positive electrode happens during the operation of the capacitor with the above-mentioned electrolyte.
In the case when the negative electrode of the electrochemical capacitor is made based on the above-described redox polymer and the positive electrode is made by another method, the molecules of the metal complex diffuse to the surface of negative electrode during the charging step and get reduced in the liquid phase during the negative electrode charging, thus, playing the role of an additional energy-accumulating substance.
If both electrodes of the electrochemical capacitor are made in accordance with the above-described method, the positive electrode is regenerated due to the mechanism described above, while the negative electrode accumulates additional energy due to the reduction of the molecules of the metal complex in the liquid phase during the charging of the electrode.
The specific features of the case when both electrodes of the electrochemical capacitor are made as a conducting substrate with a layer of an energy-accumulating redox polymer make it possible to implement a unique method of use of such a capacitor. This method comprises periodically alternating the polarity of the capacitor electrodes during the operation of the capacitor.
The step of periodical alternating of the polarity of the capacitor electrodes may be performed during the removal of the capacitor from the device where it operates or directly during the operation of the capacitor in such a device because of the appropriate switching of electrodes in the electrical circuit of the device.
Both electrodes are periodically regenerated (restored) as a result of the said switching step.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is illustrated by the following graphical materials and drawings.
FIG. 1 is a diagram of the electrochemical capacitor.
FIG. 2 is a schematic illustration of the diffusion of the metal complex molecules from the electrolyte into the redox polymer layer.
FIG. 3 is a schematic illustration of the process of incorporation of the molecules of the metal comples from the electrolyte into the redox polymer structure.
DETAILED DESCRIPTION OF THE INVENTION
An electrochemical capacitor of the present invention has the following various design features. An example of the simplest capacitor design is given in FIG. 1 . Positive electrode 2 and negative electrode 3 are placed in hermetically sealed casing 1 . Casing 1 is also filled with electrolyte 4 . The capacitor is equipped with outputs 5 and 6 (for the purpose of supplying and draining electric current) connected to electrodes 2 and 3 . Depending on the specific features of the design of the capacitor, electrodes 2 and 3 can be separated by a porous separator 7 , such as, for example, by a micro-porous polypropylene film.
It is a specific feature of the capacitor that during its operation a positive electrode of said capacitor is reduced (meaning that it restores its electrochemical characteristics), provided that the positive electrode is based on a redox polymer of a poly[Me(R-Salen)] type.
The addition of a metal complex to the electrolyte leads to a considerable increase in the amount of energy stored by the positive electrode. This increase occurs because of different chemical processes. In particular, because of the effect of “healing” of defects in the volume of the redox polymer layer of the positive during the electrode charging step and, partially, because of additional polymerization of the metal complex on the positive electrode surface.
Both processes are illustrated by FIG. 2 and FIG. 3 , which show electrode 11 consisting of conducting substrate 12 with layer 13 of the redox polymer of the poly[Me(R-Salen)] type deposited on substrate 12 (shown as fragments 14 of the redox polymer with anions 15 of the salt of electrolyte 16 attached to these fragments), in which electrolyte electrode 11 is submerged. Anions 17 and cations 18 of the electrolyte salt and molecules 19 of the metal complex (that are the components of electrolyte 16 ) are shown in FIG. 2 and FIG. 3 .
During the break intervals between the charging and discharging cycles of the capacitor (see FIG. 2 ) molecules 19 of the metal complex in electrolyte 16 diffuse in the direction of layer 13 of the redox polymer. When a voltage is supplied to the electrodes (see FIG. 3 ) during the step of charging, these molecules may get integrated into the structure of layer 13 of the redox polymer. Thus, the restoration (regeneration) of the electrochemical characteristics of the positive electrode takes place during the operation of the capacitor in such an electrolyte.
In the case when the negative electrode of the electrochemical capacitor is made on the basis of a redox polymer of the poly-[Me(R-Salen)] type and the positive electrode is made by another method, the molecules of the metal complex diffuse into the surface of the negative electrode during the charging step and get reduced in the liquid phase during the charging of the negative electrode, thus, serving as an additional energy-accumulating substance.
In the case when both of the electrodes are made on the basis of a redox polymer of the poly-[Me(R-Salen)] type, the positive electrode is regenerated in accordance with the mechanism described above, while the negative electrode accumulates additional energy due to the reduction of the metal complex molecules in the liquid phase during the electrode charging.
The above-indicated features of the design when both electrodes of the electrochemical capacitor are made as a conducting substrate with a layer of an energy-accumulating redox polymer make it possible to use the capacitor in accordance with the method of the present invention. This method comprises periodically alternating the polarity of connection of the capacitor electrodes during the operation of the capacitor, which leads to the regeneration (restoration) of the electrochemical characteristics of the capacitor electrodes.
The step of periodically alternating the polarity of the connection of the electrodes—i.e. the connection of the negative electrode to the positive pole of a power source and the connection of the positive electrode to the negative pole of a power source may be performed during operation of capacitor in the devices for which it was designed or when the capacitor is being taken out of the device.
As described above, in an electrode serving as a positive electrode the metal complex molecules diffuse into the redox polymer layer (see FIG. 2 ) during the time intervals between charging-discharging cycles. As the voltage is supplied to the electrodes during the charging process, said molecules assemble into a redox polymer structure (see FIG. 3 ). Thus, regeneration (restoration) of the electrochemical characteristics of both the positive and negative electrodes takes place during the operation of the capacitor in this electrolyte.
In addition, during the charging process the molecules of the metal complex diffuse into the surface of an electrode functioning as the negative electrode and get reduced in the liquid phase during the charging step, thus, functioning as an additional energy-accumulating substance.
To ensure that both the positive and negative electrodes are regenerated, it is necessary to periodically alternate (for example, after every 100 charging-discharging cycles) the polarity of connection of capacitor electrodes, thus, implementing the above-described processes on each electrode.
The polarity of connection of the capacitor electrodes during its service can be alternated by any known method. For instance, the regeneration of the capacitor may accomplished by removing it from the circuit and placing it into a special device in which the negative electrode of the capacitor is periodically connected to the positive pole of a power source, while the positive electrode is connected to the negative pole of the power source.
It is also possible to periodically remove the capacitor from the circuit and place it back into said circuit again in such a manner that the electrode that was previously connected to the positive pole of a power source would be connected to the negative pole of the power source (with the opposite electrode being re-connected the other way around).
The most effective way to regenerate a capacitor is to regenerate it during operation of a device in which said capacitor is used by appropriate switching of the electrodes in the electrical circuit of the device.
To experimentally verify the technical result achieved through the use of the present invention, identical electrodes (some of which were intended for testing and others—for use as reference electrodes) were manufactured. The electrodes were manufactured by electrochemical polymerization of the [Ni(Salen)] complex on a glasscarbon conducting substrate (the area of substrate surface being 38 cm 2 ). The electrolyte used for polymerization contained a solvent (acetonitrile), source complex [Ni(Salen)] having a concentration of C=10 −3 mol/l, and the tetrafluoroborate of tetrabutyl ammonium having a concentration of which was 0.1 mol/l. A polymer layer was formed on the conducting substrate surface by the electrochemical polymerization method under the conditions of a constant potential E H =1.0 V (in relation to chlorinesilver comparison electrode) for a period of t H =20 min. After the said polymer layer was formed, the electrodes were washed with acetonitrile.
The electrodes manufactured in the above-described manner were studied in electrochemical cells with different electrolytes. When the tested electrode was studied, the electrolyte contained an additive of a source metal complex. When the reference electrode was studied, the electrolyte did not contain the indicated metal complex.
The tested electrode and the reference electrode served as positive electrodes in the electrochemical cells, while the glass-graphite electrode of the same size was used as a negative electrode. The potentials of the tested electrode and the reference electrode were measured in relation to the chlorine-silver comparison electrode submerged into an electrolyte between the positive and negative electrodes.
Charging and discharging of the electrodes occurred in different electrolytes.
Charging and discharging of the tested electrode occurred in the acetonitrile solution of the tetrafluoroborate of tetrabutyl ammonium (the concentration of which was 0.1 mol/l). Said solution also contained an additive of complex [Ni(Salen)], the concentration of which was 5*10 −4 mol/l. Charging and discharging of the reference electrode occurred in the acetonitrile solution of the tetrafluoroborate of tetrabutyl ammonium (the concentration of which was 0.1 mol/l) that did not contain any additive.
The charging mode was galvano-static with the simultaneous monitoring of the potential of the electrodes, wherein the current density was equal to 30 mA/cm 2 . The charging process was stopped when the value of positive electrode potential reached 1.2 V.
Discharging of the electrode was conducted in the galvano-static mode with the simultaneous monitoring of the potential of the electrodes, wherein the current density was equal to 10 mA/cm 2 .
As a result of said studies, it was established that the value of specific energy (calculated relative to the polymer mass) stored by the electrode, charging and discharging of which occurred in the solution containing an additive of complex [Ni(Salen)], is 40–50% higher than the value of specific energy stored by the reference electrode, charging and discharging of which occurred in the solution without the additives. At the same time, the difference between the mass (weight) of the polymer on the electrode being tested and the mass (weight) of the polymer on the reference electrode after the completion of the tests was no greater than 10%.
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The invention is an electrochemical capacitor with its electrodes made on a conducting substrate with a layer of a redox polymer of the poly[Me(R-Salen)] type deposited onto the substrate. Me is a transition metal (for example, Ni, Pd, Co, Cu, Fe), R is an electron-donating substituent (for example, CH 3 O—, C 2 H 5 O—, HO—, —CH 3 ), Salen is a residue of bis(salicylaldehyde)-ethylendiamine in Schiff's base. The electrolyte comprises of an organic solvent, compounds capable of dissolving in such solvents with the resulting concentration of no less than 0.01 mol/l and dissociating with the formation of ions, which are electrochemically inactive within the range of potentials from −3.0 V to +1.5 V (for example, salts of tetramethyl ammonium, tetrapropyl ammonium, tetrabutyl ammonium), and a dissolved metal complex [Me(R-Salen)]. The method of using the capacitor contemplates periodically alternating the connection polarity of the electrodes, causing the electrochemical characteristics of the electrodes to regenerate.
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U.S. GOVERNMENT INTEREST
The inventions described herein may be manufactured, used and licensed by or for the U.S. Government for U.S. Government purposes.
FIELD OF THE DISCLOSURE
This disclosure relates generally to the field of energetic materials. More particularly, it pertains to an improved method for the preparation of insensitive bis(2,2-dinitropropyl)nitramine (BDNPN).
BACKGROUND OF THE DISCLOSURE
There is a continuing need for the development of insensitive energetic materials and in particular insensitive explosives and insensitive propellants. One such energetic material of particular interest is bis(2,2-dinitropropyl)nitramine.
SUMMARY OF THE DISCLOSURE
An advance in the art is made according to an aspect of the present disclosure directed to a method for preparing an insensitive bis(2,2-dinitropropyl)nitramine. Advantageously—and in sharp contrast to prior art methods for producing BDNPN which produces large crystals exhibiting an undesirable sensitivity—the method according to the present disclosure produces BDNPN as a very-fine, irregularly shaped material which surprisingly exhibits very desirable insensitive characteristics.
A method for preparing BDNPN according to an aspect of the present disclosure is substantially a simultaneous purification and particle-size modification process wherein crude BDNPN is dissolved in a water-soluble polar solvent and the resulting solution is then added to an ice/water slurry with stirring thereby producing the precipitation of pure BDNPN. Advantageously, the particle size of the pure BDNPN so produced is selectively variable, and is dependent upon the processing conditions (i.e., temperature, dilution, solvent, agitation rate) specifically employed to produce the physical properties and insensitivity desired.
DETAILED DESCRIPTION
The following merely illustrates the principles of the disclosure. It will thus be appreciated that those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the disclosure and are included within its spirit and scope.
Furthermore, all examples and conditional language recited herein are principally intended expressly to be only for pedagogical purposes to aid the reader in understanding the principles of the disclosure and the concepts contributed by the inventor(s) to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions.
Moreover, all statements herein reciting principles, aspects, and embodiments of the disclosure, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently-known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure.
Thus, for example, it will be appreciated by those skilled in the art that the diagrams herein represent conceptual views of illustrative structures embodying the principles of the disclosure.
By way of some additional background, it is noted that there exists a strong impetus to impart insensitive munitions (IM) characteristics to explosive and propellant formulations without compromising their performance. Of particular interest—and one aspect of the present disclosure—is the preparation and use of BDNPN to impart such insensitive characteristics to known energetic materials i.e., RDX—cyclotrimethylenetrinitramine—an explosive nitroamine widely used in military and industrial application which is also known as cyclonite, hexogen and T4.
Those skilled in the art will recognize that 3-Nitro-1,2,4-triazol-5-one (NTO) is an explosive component that is being explored as an potential insensitive replacement for RDX in explosive formulations. Although its performance is slightly less than that of RDX, NTO is thermally more stable and less sensitive to hazard stimuli. One infirmity associated with the use of NTO as an IM component is that its crystal morphology results in the isolation of acicular (needle-like) crystals that require further processing to obtain shape(s)/structure(s) suitable for use in IM formulations. As noted previously, an aspect of the present disclosure is the production of BDNPN having physical structure that advantageously formulates into a desirable IM energetic.
It is noted further that contemporary, prior art BDNPN production methods involves the dissolution of BDNPN crystals in a suitable solvent at elevated temperature and subsequently cooling the solution. This results in large crystalline BDNPN exhibiting impact sensitivity in the range of 25-35 cm. Grinding of these crystals to reduce particle size does not offer any enhanced insensitivity.
According to an aspect of the present disclosure, the process by which very fine particulate (non-needle) BDNPN exhibiting desirable IM characteristics is a simultaneous purification and particle size modification process. Advantageously, such a process interoperates with conventional processing equipment.
According to an aspect of the present disclosure, crude BDNPN is dissolved in a water-soluble polar solvent—preferably acetone at 25° C.-35° C. Those skilled in the art will appreciate that other This BDNPN solution is then added to an 1° C. to 4° C. ice/water slurry with continuous stirring. Pure (99%) BDNPN precipitates out of the solution. The precipitate is recovered and dried as very fine crystals/powder (non-needle shaped) and exhibits a particle size of approximately 5-25 microns. Advantageously this material can be utilized, without further processing, to prepare insensitive high explosive or propellant formulations.
Advantageously, the BDNPN so produced is surprisingly insensitive and exhibits an impact sensitivity over 100 cm and a shock sensitivity less than that of RDX.
At this point, while we have discussed and described the invention using some specific examples, those skilled in the art will recognize that our teachings are not so limited. Accordingly, the invention should be only limited by the scope of the claims attached hereto.
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A method for preparing an insensitive bis(2,2-dinitropropyl)nitramine (BDNPN) as a fine powder which exhibits desirable insensitive munitions (IM) characteristics for use alone or compounded with other energetic materials such as RDX.
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FIELD OF THE INVENTION
[0001] The invention relates to a process for the preparation of cis-2-tertiary-butylcyclohexanol from 2-tertiary-butylphenol, the cis-isomer being formed under the hydrogenation conditions.
BACKGROUND OF THE INVENTION
[0002] 2-tertiary-butylcyclohexanol, which can arise in the form of the cis and trans stereoisomers, is a valuable intermediate for the preparation of the fragrance 2-tertiary-butylcyclohexyl acetate. In the industrial production of 2-tertiary-butylcyclohexanol, it is desired to obtain large proportions of the cis isomer in order then, by means of transesterification, to obtain cis-2-tertiary-butylcyclohexyl acetate, which is valuable from a perfumery viewpoint and is known under the name Argrumex HC.
[0003] For the hydrogenation of 2-tertiary-butylphenol to 2-tertiary-butylcyclohexanol, noble metal catalysts, such as metallic rhodium, rhodium/platinum and rhodium/ruthenium alloys, are known, which are deposited on catalyst supports (JP-A 42-13 938). A disadvantage of the hydrogenation in the presence of a rhodium catalyst is, as well as the high cost of the catalyst, the only low stereoselectivity with regard to the cis-isomer and the decrease in the activity of the catalyst at relatively high temperatures. In addition, tertiary-butylbenzene forms in the rhodium-catalyzed hydrogenation.
[0004] DE A 3401343 describes the hydrogenation of 2-tertiary-butylphenol to 2-tertiary-butylcyclohexanol in the presence of palladium and ruthenium, the process being carried out in two stages at hydrogen pressures above 200 bar and temperatures of 70°-200° C. In the first stage, a palladium catalyst is used, and in the second stage, a ruthenium catalyst is used. The cis/trans ratio here is up to 90/10.
[0005] JP A 59/065031 describes the hydrogenation of 2-tertiary-butylphenol to 2-tertiary-butylcyclohexanol with Raney cobalt catalysis at 50 bar and 150° C., the cis:trans isomer mixture being formed in the ratio 94:6.
[0006] DE A 2909663 describes the hydrogenation of 2-tertiary-butylphenol to 2-tertiary-butylcyclohexanol with ruthenium catalysis at 40 bar and 100° C., the cis:trans isomer mixture being formed in the ratio 92.5:7.5.
[0007] JP A 49/045037 describes the hydrogenation of 2-tertiary-butylphenol to 2-tertiary-butylcyclohexanol with Raney nickel catalysis at 80 bar and 85° C. The Raney nickel catalyst is treated prior to use with aqueous sodium boronate solution. Using this catalyst treated in this way, the cis:trans isomer mixture is formed in the ratio 92:8. Without treatment of the Raney nickel catalyst, the cis:trans isomer mixture forms in the ratio 80:20.
[0008] A disadvantage of the described prior art is that the service life of the catalyst and the proportion of the cis isomer are inadequate.
SUMMARY OF THE INVENTION
[0009] Accordingly, it is an object of the present invention to provide a process which produces 2-tertiary-butylcyclohexanol with a high cis isomer content at low cost and guarantees a catalyst service life which is longer than in the prior art.
[0010] A process for the preparation of cis-2-tertiary-butylcyclohexanol has been found which is characterized in that 2-tertiary-butylphenol is hydrogenated in the presence of a nickel/iron catalyst mixture and 2-tertiary-butylcyclohexyl acetate.
DETAILED DESCRIPTION OF THE INVENTION
[0011] According to the present invention, preference is given to the use of Raney nickel/iron catalysts. The use of these catalysts in combination with 2-tertiary-butyl-cyclohexyl acetate leads to a 2-tertiary-butylcyclohexanol with a cis/trans isomer mixture of up to 95:5.
[0012] By adding 2-tertiary-butylcyclohexyl acetate, the service life of the catalyst can be considerably prolonged. It has been found that the Raney catalyst can be used more than 10 times, if 2-tertiary-butylcyclohexyl acetate is added without the cis:trans ratio falling below 90:10.
[0013] Comparative experiments have, on the other hand, shown that without the addition of 2-tertiary-butylcyclohexyl acetate in the hydrogenation, the cis:trans ratio is only 92:8. If the catalyst is used again, the cis:trans ratio decreases even more. When the catalyst is reused for only the third time without the addition of 2-tertiary-butylcyclohexyl acetate, the ratio is only 90:10.
[0014] For the process according to the present invention, the catalyst can be used in the dry or moist state.
[0015] For the process according to the present invention, in the dry catalyst, the amount of iron is 2-40% by weight, preferably 10-20% by weight; the content of nickel is 60-95% by weight, preferably 70-85% by weight, the content of aluminium is 1-20% by weight, preferably 3-10% by weight.
[0016] For the process according to the invention, the weight ratio of the catalyst used to 2-tertiary-butylphenol is (0.0001 to 0.1):1, preferably (0.01 to 0.03):1.
[0017] The weight ratio of the feed materials 2-tertiary-butylphenol and 2-tertiary-butylcyclohexyl acetate can be 100-0.2:1, preferably 7-9:1.
[0018] The reaction temperature for the process according to the invention is 50 to 200° C., preferably 90 to 130° C.
[0019] The hydrogen pressure is 1 to 100 bar, preferably 10 to 20 bar.
[0020] The reaction time is 2 to 100 hours, preferably 5 to 20 hours.
[0021] The process according to the present invention is generally carried out as follows:
[0022] A pressurized container fitted with stirrer is charged with 2-tertiary-butylphenol, 2-tertiary-butylcyclohexyl acetate and the catalyst. Hydrogenation is carried out at the chosen reaction temperature and hydrogen pressure. The resulting cis-2-tertiary-butylcyclohexanol is obtained following removal of the catalyst by filtration, decantation or centrifugation.
[0023] The resulting crude mixture can be reacted without further pretreatment with acetic anhydride to give the target product cis-2-tertiary-butylcyclohexyl acetate. Cis-2-tertiary-butylcyclohexyl acetate is a fragrance with woody-fruity properties (S. Steffen Arctander, Perfume and Flavour Chemicals, No. 438, Montclair, N.J., 1969).
EXAMPLES
Example 1
[0024] A stirred autoclave fitted with gas dispersion stirrer is charged with 520 g of 2-tertiary-butylphenol, 80 g of 2-tertiary-butylcyclohexyl acetate and 17 g of Raney nickel/iron (water content 44%, nickel content 45%, iron content 8%, aluminium content 3%). Hydrogenation is carried out for 10 hours at 130° C. and then for 3 h at 100° C. The hydrogen pressure is 20 bar. Following filtration, 605 g of a crude mixture are obtained.
[0025] According to gas chromatographic analysis, the crude mixture has the following composition:
[0026] 84.1% of cis-2-tertiary-butylcyclohexanol,
[0027] 4.6% of trans-2-tertiary-butylcyclohexanol,
[0028] 10.5% of cis-2-tertiary-butylcyclohexyl acetate,
[0029] 0.5% of trans-2-tertiary-butylcyclohexyl acetate and
[0030] 0.2% of 2-tertiary-butylcyclohexanone.
[0031] The ratio of cis:trans 2-tertiary-butylcyclohexanol is 95:5.
Examples 2-13
[0032] The following batches 2-13 proceed analogously to 1, the catalyst from the starting batch 1 being reused. The cis:trans ratio varies between 94:6 and 91:9.
[0033] Although the invention has been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that variations can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.
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The present invention relates to a process for the preparation of cis-2-tertiary-butylcyclohexanol, where 2-tertiary-butylphenol is hydrogenated in the presence of a nickel/iron catalyst mixture and 2-tertiary-butylcyclohexyl acetate.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of application Ser. No. 09/481,046, filed Jan. 11, 2000; which is divisional application of application Ser. No. 09/040,985, filed on Mar. 18, 1998, now U.S. Pat. No. 6,012,272; and is cross-referenced to application Ser. No. 09/210,331, filed Dec. 11, 1998.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
[0002] Not applicable.
BACKGROUND OF THE INVENTION
[0003] The present invention generally relates to combines and more particularly to an articulated (jointed) combine which employs, inter alia, an improved joint, unloading capability, grain transfer capability, airbag suspension, straw and chaff conveyor, suspended/movable fuel tank, control/steering, and extremely large grain storage capacity.
[0004] A modern agricultural combine typically unloads or transfers clean grain from its on-board storage hopper utilizing an auger of fixed length which swings out in a fixed radius and fixed elevation arc from its stowed position. The stowed position generally is pointing to the rear of the combine. The auger in turn generally is driven by a mechanical arrangement of belts, chains, clutch, and gearbox. The unload auger in most combine designs swings out to the operator's left. The auger length generally is limited by the practical distance that it can extend beyond the rear of the combine in its stowed position without creating a serious maneuvering hazard.
[0005] As the size of on-board storage hoppers and capacity of combines has increased, the time required to maneuver the machine next to the grain receiving wagon or truck and the grain transfer time have become a major component of the total harvesting time. Conventional combines have a grain hopper capacity of 250 to 300 bushels and unload auger capacities of 1.9 to 2.6 bushels per second.
[0006] The unload time of the hopper typically is about 2 to 3 minutes with the unload auger running at maximum speed and 1 to 2 minutes are taken to maneuver the combine into the optimum unload position next to the truck or wagon. Re-positioning the combine and running the auger at less than maximum speed are often encountered when topping off the truck or wagon which is receiving the grain. As modem combine harvesting capacities approach 3,000 bushes per hour, the unload cycle must be repeated every 8 to 10 minutes. Therefore, the total unload time or non-harvesting time is a significant reduction of total grain harvesting productivity. A grain capacity of about 600-450 bushels would permit the combine to harvest for about 1 mile, which would greatly reduce unloading cycles.
[0007] This productivity loss can be countered by a second operator utilizing a tractor and grain cart following the combine back and forth through the field to unload the on-board combine storage hopper without stopping the harvesting process. Alternatively, a combine with an integrated grain cart, as disclosed in applicant's U.S. Pat. No. 5,904,365 can be utilized to reduce the number of unload cycles and at least double the rate at which grain is discharged to the receiving vehicle.
[0008] Unloading combines into semi-trailer road trucks has become the prevalent practice as opposed to field wagons that were utilized in the past. These road trucks typically are parked at the side of the road and not in the field where the combine is operating. This necessary practice almost always creates an elevational difference between the two vehicles. These road trucks themselves also have widely varying heights. These two conditions create a big variation in the optimum elevation of the discharge point of the combine unloading system. Combine manufacturers have attempted to address this problem with ever-longer augers and higher fixed swing out arcs. There are, however, limits to both. This fixed point discharge point frequently ends up too high, too low, too far from the combine, or too close to the combine for optimum truck loading conditions. Such conditions require repositioning the combine with respect to the vehicle while it is unloading.
[0009] Existing combine unloading systems can unload from one side of the machine only. This frequently requires 180° turns by the combine to position it on the proper side to unload the grain into the road truck. It also means that while harvesting the combine generally only can be unloaded into a moving grain cart only while traveling along the left-hand side of the unharvested crop since access to the unloader would be precluded by the unharvested crop were the combine to be located to the right of the crop.
[0010] When topping off or completely filling the truck or wagon, it is necessary for the operator to inch the combine forward or backward during the process. In addition to being cumbersome, the combine must be positioned close to perfectly parallel to the receiving vehicle or a stop and reposition is necessary. Moving the auger through its fixed arc frequently cannot solve the lack of parallel orientation.
[0011] An agricultural combine has multiple steering requirements. Precise control is needed as the row harvesting units such as a cornhead, are guided through the rows of grain. When the end of the field is reached, a tight turning radius is needed to proceed back across the field in order to harvest the crop immediately adjacent to the just-completed rows or round. Concomitant with its field performance, this large vehicle also must be controlled on the roadway at speeds of around 20 mph and around tight corners. Another steering associated problem is to turn multiple axle, heavily-loaded bogies with large tires in a tight radius while minimizing sliding the tires in the horizontal (particularly in the lateral) direction, which places high stresses in the suspension, piles up dirt in the field, and causes excessive tire wear.
[0012] Early attempts at an articulated combine are reported in U.S. Pats. Nos. 4,317,326 and 4,414,794. The design capacity is stated to be around 360 bushels. Its unloading mechanism is limited to one side of the combine and steering is accomplished only by articulation steering cylinders. U.S. Pat No. 4,453,614 proposes a steering cylinder arrangement for an articulated combine. U.S. Pat. No. 4,204,386 proposes an articulated machine for gathering vegetables. U.S. Pat. No. 5,857,907 proposes a discharge conveyor having a secondary, variably extending conveyor attached to the terminal end of the discharge conveyor.
[0013] U.S. Pat. No. 6,012,272 (the '272 patent) discloses an articulated combine composed of a forward unit or bogey having an operator's cab, engine, grain harvesting assembly, grain transfer assembly, but no on-board grain storage; and a rear unit or bogey jointedly attached to the forward unit and having a steerable and powered wheel assembly, an on-board grain storage bin, and a grain off-loading assembly. Many of the industry long-felt, but unsolved needs regarding articulated combines are disclosed in the '272 patent. Basic improvements thereto are the subject of this application.
BRIEF SUMMARY OF THE INVENTION
[0014] One aspect of the present invention is a combine having increased on-board grain storage capacity. The combine includes a forward unit having an operator's cab, an engine, a grain harvesting assembly, a grain transfer assembly, and is devoid of an on-board grain bin. The combine also has a rearward unit jointedly attached to the forward section. The rearward unit has a powered wheel assembly, an onboard grain bin for receiving grain from the forward section grain transfer assembly, and a grain off-loading assembly.
[0015] Another aspect of the present invention is directed to a joint for a powered articulated vehicle, such as a combine for joining a forward unit to a rearward unit. The joint includes an upper frame member carried by the forward unit and having a recess on its lower side and a lower frame member carried by the forward unit, having a recess on its upper side, and being spaced-apart vertically below the upper frame member so that the recesses are in vertical registration. The joint further includes a shaft carried by the rearward unit and a bearing retainer assembly carried by the end of the shaft and disposed between the recesses. The bearing assembly includes an outer annulus surmounting an inner hub which hub is connected to the shaft with thrust bearings inserted between the annulus and said hub, whereby the inner hub co-rotates with shaft with respect to the outer annulus. The bearing assembly also includes a pair of nibs carried by the outer annulus which nibs reside in the upper and lower recesses and which nibs are associated with tapered roller bearings so that the outer annulus co-twists with the shaft respect to the forward unit. Uniquely, the joint is stiff in the vertical plane through the longitudinal axis formed along the forward unit frame members and the rear unit shaft, i.e., around the pitch axis. It will be appreciated that the upper and lower frame members could be carried by the rearward unit and the shaft carried by the forward unit and the novel joint would function the same as with the configuration set forth above.
[0016] A further aspect of the present invention is an improved articulated combine comprising a forward unit connected by a joint to a rearward unit. The improvement for transferring clean grain from the forward unit to the rearward unit includes the rearward unit carrying an onboard grain bin and having a front wall that has a horizontal slot therein. The front wall retains a horizontally elongate grain transfer trough affixed thereto which trough is curved with its center of curvature congruent with the center of articulation of the combine. The trough is in communication with the bin via the slot. The forward unit carries a grain transfer assembly of a fixed elongate discharge chute that empties into the rearward unit trough while the forward and rearward units are being turned about the joint.
[0017] A still further aspect of the present invention is a grain unloading assembly for unloading clean grain from a combine grain bin, wherein a combine harvests grain and cleans it to provide the clean grain. Such grain unloading assembly includes a vertical flighted conveyor that is adapted to operate in either direction. Also included is a housing in which the vertical flighted conveyor is disposed. The housing is fitted at its top with a bin spout, a discharge spout, a moveable door that permits communication of the flighted conveyor either with the bin spout or with the discharge spout. A first opening at the bottom of the housing is covered with a moveable door for permitting grain in the bin to be moved into the housing for conveying by the flighted conveyor. A second opening at its bottom of the housing is for permitting clean grain to be passed into the housing from the combine.
[0018] Yet another aspect of the present invention is an unload assembly for unloading clean grain from a combine grain bin. This unload assembly includes a distal frame nested within a proximal frame. The distal frame is extensible from and retractable into the proximal frame. The distal frame has a discharge end for discharging grain. The proximal frame has a feed end for receiving grain from the grain bin and a distal end from which the nested distal frame extends and retracts. This unload assembly further includes a conveyor system that includes a first fixed pulley located at the feed end of the proximal frame. A second fixed pulley is located at the discharge end of the distal frame. A third fixed pulley is located at the distal end of the proximal frame. A fourth moveable pulley is disposed within the proximal frame intermediate the first and third fixed pulleys. The conveyor extends from the first pulley to the second pulley to the fourth pulley to the third pulley and back to the first pulley.- A fifth pulley may be employed near the first pulley to increase the wrap angle of the conveyor belt around the first pulley. This arrangement permits the conveyor to extend as the distal conveyor extends and retracts as the distal conveyor retracts by movement of the fourth pulley.
[0019] Still a yet further aspect of the present invention is a straw and chaff spreader for mounting in association with a grain cleaner of a combine. This spreader includes a pair of generally horizontally-disposed, outwardly rotating, cleated conveyors disposed to receive straw and chaff discharged from the grain separator and cleaner of a combine.
[0020] A yet further aspect of the present invention is an airbag suspension for a vehicle having a vehicle frame having an axle (stub or through axle) extending therefrom. A longitudinal beam is affixed to the axle that carries at least one wheel. An airbag assembly includes an upper plate extending from the vehicle frame, a lower plate affixed to the longitudinal beam, and an airbag disposed between the upper and lower plates. The lower plate carries a pair of vertical blocks having vertical slots. A pair of cams is carried by the upper plate and rides in the vertical slots.
[0021] Another aspect of the present invention is a steering system for an articulated vehicle having a joint that connects a forward unit and a rearward unit and at least one articulation cylinder to provide a turning force at the joint. The steering system includes an operator speed and direction mechanism whereby an operator can direct the desired direction of the vehicle. A power source is provided for driving pumps adapted to drive motors and cylinders. The forward unit has tractive wheels (tired or tracked) powered by one or more motors. Each motor has a transducer for measuring its rotational speed and direction. The rearward unit has a pair of tractive endless tracks or tired wheels each powered by a separate motor. Each motor has a transducer for measuring its rotational speed. A programmable controller receives the rotational speed measurements (for over-speed control) and pressures from all of the transducers and operator steering commands from the speed and direction mechanism, and responds with suitable outputs. Actuators receive the controller outputs and adjust the output of each of the motors powering the rearward unit tracks/wheels.
[0022] A still further aspect of the present invention is an improved combine having a fuel tank, and which includes an overhead rail from which the fuel tank is suspended and an optional actuator connected to the fuel tank for moving the fuel tank forwardly and rearwardly. Desirably, though, the fuel tank can be moved forwardly and rearwardly by hand.
[0023] A still further aspect of the present invention is a method for articulating an articulated vehicle at a rest position wherein the vehicle is composed of a forward unit and a tracked rearward unit having a pair of powered tracks. The forward and rearward units are connected by a joint and an articulation cylinder. The method powers up only one track while simultaneously actuating the articulation cylinder.
[0024] Advantages of the present invention include a combine design, preferably an articulated combine, which enables grain storage capacity of between 500 and 1,000 bushels or more. Another advantage is an articulated combine which can unload clean grain to either side and which is controlled by a unique control system. A further advantage is a unique steering system for an articulated combine. These and other advantages will be readily apparent to those skilled in this art.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] For a fuller understanding of the nature and objects of the present invention, reference should be had to the following detailed description taken in connection with the accompanying drawings in which:
[0026] [0026]FIG. 1 is a side elevational view of the novel combine (or harvester) with, inter alia, extra large storage capacity, straw and chaff conveyor, novel joint, clean grain transfer ability, and unloading capacity;
[0027] [0027]FIG. 2 is a side elevational view of the other side of the novel combine depicted in FIG. 1. fitted with caster wheels at the rear of the front unit;
[0028] [0028]FIG. 3 is an overhead view of the combine depicted in FIG. 1;
[0029] [0029]FIG. 4 is a rear view of the rear unit of the combine depicted in FIG. 1;
[0030] [0030]FIG. 5 is a sectional view taken along line 5 - 5 of FIG. 1;
[0031] [0031]FIG. 6 is a sectional view taken along line 66 of FIG. 5 showing a plan view in greater detail of joint 22 ;
[0032] [0032]FIG. 7 is a sectional view taken along line 7 - 7 of FIG. 6;
[0033] [0033]FIG. 8 is a sectional view like that taken along line 7 - 7 , but of a preferred embodiment of the joint of FIG. 6;
[0034] [0034]FIG. 9 is a sectional view taken along line 9 - 9 of FIG. 8;
[0035] [0035]FIG. 10 is an overhead view of the straw and chaff conveyor system fitted at the rear of the front unit of the novel combine;
[0036] [0036]FIG. 11 is a side cut-away view of the rear unit of the novel combine showing the grain transfer system between the front and rear units and the grain handling system aboard the rear grain bin unit;
[0037] [0037]FIG. 12 is a rear cut-away view of the rear unit of the novel combine showing part of the grain handling system aboard the rear grain bin unit;
[0038] [0038]FIG. 13 is a side cut-away view of the hydraulic nested grain off-loading assembly in its retracted position;
[0039] [0039]FIG. 14 is a side cut-away view of the hydraulic nested grain off-loading assembly in its extended position;
[0040] [0040]FIG. 15 is a partial side elevational view of a joystick used to control the clean grain transfer assembly depicted in FIGS. 13 and 14;
[0041] [0041]FIG. 16 is a top view of the joystick shown in FIG. 15;
[0042] [0042]FIG. 17 is a schematic of the hydraulic vertical control for the clean grain transfer assembly of FIGS. 13 and 14;
[0043] [0043]FIG. 18 is a schematic of the hydraulic swing control for the clean grain transfer assembly of FIGS. 13 and 14;
[0044] [0044]FIG. 19 is a schematic of the hydraulic telescoping control for the clean grain transfer assembly of FIGS. 13 and 14;
[0045] [0045]FIG. 20 is a schematic of the hydraulic speed control for the clean grain transfer assembly of FIGS. 13 and 14;
[0046] [0046]FIG. 21 is a side elevational view of the novel suspension system of the rear grain bin unit;
[0047] [0047]FIG. 22 is a sectional view taken along line 22 - 22 of FIG. 15;
[0048] [0048]FIG. 23 is a sectional view taken along line 21 - 21 of FIG. 15;
[0049] [0049]FIG. 24 is a side elevational view of a combine like that depicted in FIG. 1, except that the rear unit is wheeled rather than fitted with an endless track;
[0050] [0050]FIG. 25 is a rear elevational view of the combine in FIG. 24;
[0051] [0051]FIG. 26 is an overhead view of the combine in FIG. 24;
[0052] [0052]FIG. 27 is a partial sectional view of the suspension system of the combine in FIG. 24;
[0053] [0053]FIG. 28 is a simplified overhead schematic of the turning geometry for a wheeled rear unit embodiment of the present invention; and
[0054] [0054]FIG. 29 is a schematic of the hydraulic steering system for the novel articulated combine.
[0055] The drawings will be described in detail below.
DETAILED DESCRIPTION OF THE INVENTION
[0056] The present invention provides basic improvements to the '272 patent articulated combine, which disclosed solutions to many problems associated with modem farming combines by providing a harvester that can unload readily on either side and to virtually any height road truck. The disclosed harvester retains the increased capacity of harvested grain carrying capacity from about 200-300 bushels in conventional combines to about 500-1,200 bushels utilizing the rearward-only grain bin, because the rearward unit has more capacity (space) than there is in a grain bin located over a front axle. This is important because the capacity of a typical road semi-trailer is 1,000 bushels. This means that the disclosed combine can fill an entire road truck from its on-board grain bin in a single unloading. Moreover, a unique, unloading system permits unloading of clean grain from the rearward grain bin unit out to either side of the combine. Such increased grain storage capacity is possible because the grain bin is located on the rearward unit, which permits a much lower center of gravity to be designed into the rearward unit.
[0057] In order to ensure that the extra weight can be easily maneuvered by the novel harvester, the rearward unit has powered and steerable wheels that are supported by a unique airbag suspension system. A new dean grain transfer assembly for transferring clean grain from the forward unit to the rearward cart bin unit also is disclosed. An improved two-axis joint interconnects the forward and rearward units. Straw and chaff from the harvesting assembly is discharged to either side by a unique dual conveyor system. “Wheels” or “wheeled” for present purposes includes both wheels that are fitted with tires (pneumatic tires) and wheels that are fitted with endless tracks.
[0058] Referring initially to FIGS. 1, 2 and 3 , innovative combine 10 generally includes forward unit 12 and rearward unit 14 . Forward unit 12 is seen to include cab 15 in which the operator is seated, cornhead or small grainhead 16 , engine compartment 18 (two cooling fan air inlets shown in the drawings), and powered non-steerable wheel pair 20 . In the alternative embodiment in FIG. 2, forward unit 12 is fitted with caster wheel pair 19 located at the rear of forward unit 12 . Rearward unit 14 is interconnected to forward unit 12 via joint assembly 22 and clean grain is transferred from forward unit 12 to rearward unit 14 via clean grain transfer assembly 24 . Rearward unit 14 is seen to include clean grain unloading system 26 in its stored position and in phantom in two possible raised unloading positions in FIG. 3, grain bin 28 , and powered endless tracks 30 and 32 . Use of a dual track system supporting grain bin 28 on rearward unit 14 contributes to the capability of grain bin 28 holding upwards to 1,200 bushels of grain. Providing the grain bin capacity only on rearward unit 14 translates into a lower center of gravity for grain bin 28 which also enables such higher storage capacity and provides more even weight distribution per axle. Importantly, at about 600-650 bushel capacity of grain bin 28 , combine 10 could harvest, for example, a cornfield for one mile before unloading. Capacity in excess of requirement means that combine 10 can harvest for even greater distances before unloading.
[0059] As seen in FIG. 2, fuel tank 34 is carried suspended by rail 36 and is moveable from a forward to a rearward position as indicated by arrow 38 . Movement of suspended fuel tank 34 ensures access to, for example, hydraulic lines and other components should such access be necessary, desirable, or convenient. Such fuel tank movement also enables weight shifting of forward unit 12 , should such weight shifting also be necessary, desirable, or convenient.
[0060] As seen in FIG. 4, grain bin 28 is fitted with ladder 40 for operator access to the interior of grain bin 28 . Grain bin 28 also is fitted a pair of light arrays, 42 and 44 , as the combine may traverse roadways in order to access field to harvest. Other items of interest in this rear view of the combine will be discussed later in connection with other features of the novel articulated combine.
[0061] Referring to FIGS. 5, 6 and 7 that illustrate joint 22 , initially, it will be observed that a pair of steering cylinders, 46 and 48 , are seen in FIG. 5 to connect forward unit 12 to rearward unit 14 of articulated combine 10 . Such steering cylinders are conventionally used to assist in the steering of articulated vehicles and are provided here for such steering use in the present articulated combine design. Now, with respect to the two-axis joint, pipe 50 is attached to rearward unit 14 at one end and is constructed as a round pipe or structural tube. Shaft 52 extends from pipe 50 towards forward unit 12 and is inserted into bearing retainer assembly 60 which is inserted between upper frame member 54 and lower frame member 56 . These frame members 54 and 56 are bolted to forward unit 12 via bolts 58 a - d ; although, other attachment means certainly can be envisioned. Each frame member 54 and 56 has an inner recess that confronts the corresponding recess in the other and into which is inserted bearing retainer assembly 60 .
[0062] Bearing retainer assembly 60 has a pair of nibs or ears which fit into frame member 54 and 56 recesses and which ride on tapered roller bearing 62 a - 62 b to provide sideways movement to units 12 and 14 via pipe 50 . Such sideways movement permits combine 10 to be steered. A hole penetrates through bearing retainer assembly 60 into which a reduced-diameter threaded end of shaft 52 fits and is secured via nut 64 . Now, thrust bearings 66 and 68 fit into counterbores that adjoin the hole through bearing retainer assembly 60 and which thrust bearings permit shaft 52 to rotate and which, thus, enables units 12 and 14 to rotate with respect to each other. Such rotation permits units 12 and 14 to traverse uneven terrain during harvesting or other movement of combine 10 . Note, however, that pipe 50 and shaft 52 are not permitted to move in a vertical direction due to the unique construction of joint assembly 22 . Thus, a unique dual axis joint has been disclosed. I should be understood that the connection of joint 22 could be the reverse of that connection depicted in FIGS. 5, 6, and 7 . That is, pipe 50 could be attached to forward unit 12 rather than rearward unit 14 .
[0063] A modified version of the joint depicted in FIGS. 6 and 7 has now been designed and is illustrated in FIGS. 8 and 9. It utilizes the features of joint 22 of FIGS. 6 and 7, except that additional thrust bearings have been added to take up the additional separational forces that joint 22 sees due to taped roller bearings 62 and 66 . Also, the joint in FIGS. 8 and 9 has been rotated 180° so shaft 52 now is connected to forward unit 12 , rather than to rearward unit 14 via pipe 50 , as is shown in FIGS. 6 and 7. Also, frame members 54 and 56 are removably attached to frame member 59 that is connected to rear unit 14 . Additionally, spacers 51 are held in place by threaded bolts 53 and 55 , which fit through holes in frame members 54 and 56 , respectively. The basic construction of the joint in FIGS. 8 and 9 is like that for joint 22 , except that frame members 54 / 56 have apertures into which flanged plug assemblies 70 and 72 are placed and held securely by threaded members 74 and 76 , respectively. Recesses adjacent the apertures in frame members 54 / 56 contain races into which thrust bearings 78 and 80 , respectively fit and are retained by the flared heads of flanged plugs 70 and 72 . Flanged plug assemblies 70 and 72 include spacers (not shown in the drawings) to ensure that tapered roller bearings 62 and 66 are not excessively pre-loaded when flanged plugs 70 and 72 are tightened and washers (not shown in the drawings) are provided for the flanges of plugs 70 and 72 to bear against when tightened.
[0064] Regarding to the novel two-axis joint as disclosed in the '272 patent, unique to joint 22 is that it is a “single point” joint. That is, joint 22 is designed to be only about a foot or so high. No other structural connection between forward unit 12 and rearward unit 14 is required by dint of the design of joint 22 . That is not to say that other structural connection cannot be made between forward unit 12 and rearward unit 14 , but that no other structural connection is necessary. In fact, it is a positive advantage that no other structural interconnection is needed between the two units because the combine designer has greater flexibility in locating equipment, lines, feeders, etc. because of the single point joint design disclosed herein.
[0065] Referring now to FIG. 10, the description will commence with the transfer of clean grain from forward unit 12 to grain bin 28 and will be completed with off-loading of the grain into, e.g., a semi-truck. In this regard, clean grain and straw and chaff separately exit from grain cleaner assembly 82 (which is quite conventional). The straw and chaff falls down onto dual conveyors 84 and 86 that are separately driven by hydraulic motors 88 and 90 , respectively. Alternatively, conveyors 84 and 86 could be driven by a single motor with appropriate gearing, belts, or the like, providing for the movement of the non-driven conveyor either in the same direction or in the opposite direction from the driven conveyor. Conveyors 84 / 86 also can be seen in FIGS. 1 - 3 to be located above joint assembly 22 . In normal operation where combine 10 is traveling through the field harvesting grain, conveyors 84 and 86 each rotate so as to throw the straw and chaff outwardly from combine 10 . During a turn, it may be advantageous to not bunch up straw and chaff under the rear wheels of rearward unit 14 , so both conveyors can be set to throw the straw and chaff to the side of combine 10 that is opposite the direction of the turn. Since conveyors 84 / 86 desirably are separately powered, they can be rotated in the same direction or in opposite directions. Regardless of the direction of their turning, conveyors 84 / 86 ensure that the straw and chaff will not fall down on joint assembly 22 nor bunch up directly underneath combine 10 for rearward unit 14 to traverse over.
[0066] The clean grain from the grain cleaning operation aboard forward unit 12 travels to clean grain transfer assembly 24 (see FIGS. 1 - 3 and 11 ). Referring especially to FIG. 11, it will be observed that clean grain passes down fixed elongate discharge chute 92 into elongate horizontal trough 94 that is connected to the forward wall of grain bin 28 . From FIG. 3, it can be seen that the front of trough 94 is curved (or arcuate) to match the radius of curvature of articulation of combine 10 . Such curvature ensures that fixed chute 92 always will empty clean grain into trough 94 even while combine 10 is turning (articulating). Now front wall 96 of grain bin 28 has slot 98 that permits clean grain in trough 94 to be passed to the inside (or cavity) of bin 28 . The design of clean grain transfer assembly 24 is simple in that gravity is used to feed the clean grain from forward unit 12 into trough 94 via chute 92 . Gravity also ensures that the clean grain in trough 94 passes through slot 98 into grain bin 28 .
[0067] The clean grain passing through slot 98 enters vertical conveyor system 100 that passes the clean grain into bin 28 and also to clean grain off-loading assembly 26 . As such, vertical conveyor assembly 100 is central to proper grain handling within grain bin 28 . To that end, vertical conveyor system 100 includes flighted (paddled) conveyor 102 disposed within housing assembly 104 . Conveyor 102 is driven by hydraulic motor 106 (see FIG. 4) and its direction is reversible and its speed is variable. At the top of conveyor assembly 100 are a pair of discharge chutes, 108 and 110 (which will be described later). Moveable door 112 powered by hydraulic cylinder 115 (see FIG. 2) permits clean grain to be discharged either by chute 108 , chute 110 or both with the direction of conveyor 102 being coordinated with the position of door 112 . With door 112 in the position shown in FIG. 11, conveyor 112 would be set to rotate in the counterclockwise direction by motor 106 (the direction of rotation is given with respect to FIG. 11, as direction of movement is determined by the position of the observer). Grain entering housing 104 via slot 98 would be discharged into grain bin 28 . When door 112 is moved into the dashed line position and the direction of conveyor 102 reversed, grain would be discharged through chute 110 into unload assembly 26 , which will described in detail below. It is possible to unload bin 28 while harvesting as also will be described below. Due to all the grain being dumped into bin 28 through chute 110 , top leveling augers also can be provided to even out the clean grain stored in grain bin 28 .
[0068] To continue with the flow of clean grain, once clean grain enters bin 28 , it is stored there until it is required to be discharged. Referring to FIGS. 3, 5, 11 , and 12 , the first step is clean grain discharge commences with a unique floor design that includes drag paddles 114 and 116 that are powered by hydraulic motor 118 (see FIG. 4) that can be accessed via door 120 at the rear of grain bin 28 . Drag paddles 114 / 116 essentially create a fluidized bed of grain that is fed from bin 28 through moveable door 122 that is powered by hydraulic cylinder 124 (see FIG. 11) and into housing 104 . It will be appreciated that augers or the like could replace drag paddles 114 / 116 ; although, the flatness of paddles permits bin 28 to have a flat floor which increases the grain capacity of bin 28 . In order to prevent the grain in bin 28 from stopping the movement of drag paddles 114 / 116 and in order to meter grain to such drag paddles, adjustable inverted-V floor assembly 126 is stationed just above drag paddles 114 / 116 (see FIGS. 3 and 12). Moveable doors or the like could substitute therefor. It will be appreciated that each inverted-V (e.g., V 128 ) retains a pair of adjustable louvers (e.g., louvers 130 and 132 ) that can finely adjust the openings between each inverted-V. Such louver arrangement provides for precise metering of grain from bin 28 to drag paddles 114 / 116 . Louvers 130 / 132 can be adjusted manually; although, hydraulic adjustment could be provided.
[0069] Now that drag paddles have pulled/pushed the clean grain into housing 104 , if conveyor 102 rotated in a clockwise direction with door 112 actuated to the dashed line position (i.e., chute 108 closed and chute 110 open), then clean grain in bin 28 will be conveyed by conveyor 102 up through housing 104 and be discharged via chute 110 onto clean grain unloading system 26 . Should combine 10 be harvesting field grain while off-loading is progressing, then not only will grain housed within grain bin 28 be off-loaded (unloaded), but so too will clean grain entering housing 104 via slot 98 from grain transfer system 24 . Thus, the novel combine has the capability of harvesting and unloading grain concurrently. Once clean grain in grain bin 28 has been off-loaded, door 112 is moved to its position as shown in FIG. 11 and conveyor 102 reversed in its direction of travel to then throw clean grain back into bin 28 .
[0070] Clean grain unloading system 26 (see FIGS. 2 and 13) includes nested conveyor assembly 134 , which includes distal frame 136 with grain chute 137 nested within proximal frame 138 . Housed within frames 136 / 138 is cleated (or flighted) endless conveyor belt 140 . Nested conveyor assembly 134 rests on cradle 142 that is formed from a shaft (not seen in the drawings) and rollers, such as roller 144 (see FIG. 3). Cradle 142 permits the nested conveyor assembly 134 to move along its longitudinal axis with respect to cradle 142 when combine 10 articulates. Rotational power is not supplied to conveyor assembly 134 when no clean grain unloading is taking place so that it is in a float or relaxed mode; thus, permitting conveyor assembly 134 to be rotated by cradle 142 when combine 10 articulates. Chute 110 transfers clean grain through an aperture in proximal housing 138 directly above the pivot point, pivot assembly 146 (see FIGS. 13 and 14), for conveyor assembly 134 so that the transfer location does not change as the conveyor rotates from side to side during unloading.
[0071] Nested conveyor assembly 134 is lifted by pistons 148 and 150 , which are attached to cable 152 that runs through snatch block 154 which in turn is connected to rearward unit 14 by frame assembly 156 (see FIGS. 2 and 3). Such lifting mechanism also has its pivot point in line with the axis of rotation of conveyor assembly 134 so that conveyor assembly 134 does not change height as it is rotated from side to side, such as is shown in phantom in FIG. 3. Such lifting mechanism's connection to rearward unit 14 is moment decoupled to prevent conveyor assembly 134 from twisting as it rotates by means of the universal attachment of snatch block 154 which is permitted to move in all three axes. Alternatively, rod end Heim joints could be placed at the ends of an adjustable rod in place of cable 152 .
[0072] Referring to FIGS. 2, 11, 13 , and 14 , nested conveyor assembly 134 is rotated from side-to-side by wheel or sprocket 158 that is supported by shaft 159 for rotation of sprocket 158 , a chain that encircles sprocket 158 (not readily seen in the drawings), and hydraulic motor 160 which pulls the chain through a small sprocket (also not readily seen in the drawings). Conveyor assembly 134 is supported by pivot assembly 146 , which permits conveyor assembly 134 to be inclined upwards. The center of wheel 158 establishes both the axis of rotation and the axis of inclination of conveyor assembly 134 . Pivot assembly 146 includes a shaft disposed vertically through its center hub, which shaft is supported by an outer hub that is tied to rearward unit 14 via structure 162 . Additional structural stability and support (not shown in the drawings) for wheel 158 is provided by cam follower-type rollers that are disposed under the periphery of wheel 158 and tied to structure 162 . This additional support can be helpful as the conveyor rotates which causes a torque load to be introduced into the center support shaft at various angles.
[0073] Endless conveyor 140 is driven by hydraulic motor 164 (see FIG. 2), which connects to drive pulley 166 (see FIGS. 13 and 14). From fixed drive pulley 166 , belt 140 goes to stationary pulley 168 located in distal frame 136 , back to moveable pulley 170 , to fixed pulley 172 , to idler pulley 174 , and back to drive pulley 166 . Note that moveable pulley 170 is located between fixed pulleys 166 and 172 . As distal frame 136 is extended from proximal frame 138 by hydraulic motor 151 associated with pinion 153 and rack 155 , pulley 170 , which otherwise is biased inwardly, moves from a position such as is illustrated in FIG. 13 to a position such as is illustrated in FIG. 14. Hydraulic motor 151 is mounted at the distal end of proximal frame 138 along with pinion 153 . Rack 155 is mounted at the proximal end of distal frame 136 and is driven by pinion 153 to extend/retract distal frame 136 . Chute 137 in turn extends from its home position to an extended position so that clean grain can be unloaded, for example, into a waiting semi-trailer. Frames 136 and 138 preferably are shrouded or covered to aid in grain retention during operation of belt 140 .
[0074] With respect to operation of clean grain unloading system 26 , reference is made to FIGS. 15 and 16 which show the unique joystick control system of the '272 patent which can be adapted to control the present unloading system. Initially, joystick 200 is fitted with finger toggle switches 202 , 204 , 206 , and button 208 . The operator's fingers activate toggle switch 202 that causes unloading system 26 to move vertically up and down. Switch 204 conveniently is thumb activated and is an on-off switch for unloading system 26 . Switch 206 is a combine inching switch; that is, it causes combine 10 to move slowly forward or backward to place spout 137 exactly where the operator desires. Such slow movement is known as “inching” in this field. Button 208 is a “home” button that means that unloading system 26 is returned to its stored position as shown in FIG. 3, for example.
[0075] Another capability of joystick 200 is that it can move forward, backward, and laterally left and right. These movements cause unloading system 26 to extend (say, forward movement of joystick 200 ), retract (backward movement), swing to the left (left movement), and swing to the right (right movement). Finally, joystick 200 is rotatable to control the speed of the belt 140 of unloading system 26 .
[0076] Joystick 200 accomplishes the described movements of unloading system 26 by signaling electrohydraulic valves with a signal sent to manually adjustable flow control valves for, say, movement of unloading system 26 up/down, left/right, in/out, and home. Joystick 200 signals a proportional servo valve for on/off and conveyor speed (e.g., activates a linear electric servo that moves a pump swash plate). Joystick 200 signals the propulsion system of combine 10 in order to inch the combine forward or reverse by by-passing the normal operator speed control of the vehicle. It should be obvious that the novel combine takes advantage of the hydraulic system already in place in conventional combines and extends their use in order to power desirably the unloading system 26 and tracks 30 and 32 . Other power means, of course, could be employed; however, hydraulic power tends to be more reliable.
[0077] In the unloading or off-loading mode, belt 140 always is actuated first and turned off last in order to minimize any plugging problems. Next, the direction of vertical conveyor 102 is reversed from the grain harvesting mode and its speed is increased. Door 122 is opened and grain fed by gravity to conveyor 102 until a sensor indicates that the amount of gravity fed grain slows down. At this point, drag paddles 114 / 116 are activated to feed conveyor 102 .
[0078] Implementation of such joystick movements of unloading system 26 is displayed in FIGS. 17 - 19 . Referring initially to FIG. 17, lines 210 and 212 are connected to a source of voltage (say, 12 volts supplied by the combine). Contacts 214 and 216 are joystick 200 contacts for raising and lowering, respectively, conveyor assembly 134 of unloading system 26 . Ground 217 is provided in conventional fashion. Upon closure of one of joystick contacts 214 or 216 , bi-directional valve with adjustable flow 218 is fed hydraulic fluid at, say, 2,000 psi from a hydraulic pump which feeds rod and cylinder assemblies (pistons) 148 / 150 via lines 220 and 222 with oil returned to reservoir 224 via line 226 . Assembly 134 , then, raises and lowers unloading system 26 (conveyor assembly 134 ).
[0079] Referring to FIG. 18, lines 228 and 230 run to joystick contacts 232 and 234 which actuate bi-directional valve with adjustable flow and float 236 which actuates motor 160 for swinging unloading system 26 either left or right. Ground 238 and return line 239 to reservoir 224 are provided in conventional fashion. A rod and cylinder or other means could be substituted for motor 160 .
[0080] Referring to FIG. 19, lines 240 and 242 run to joystick contacts 244 and 246 which actuate bi-directional two flow valve (slow/fast speed) 248 which actuates motor 151 for extending distal frame 136 from its nested position within frame 138 . Ground 250 and return line 254 to reservoir 224 are conventionally provided. A rod and cylinder or other means could be substituted for motor 151 .
[0081] Referring to FIG. 20, the unload system speed control is shown. Specifically, combine engine 256 is connected via line 258 to pump 260 , which is a variable displacement pump. Pump 258 is in fluid (oil or hydraulic fluid) communication with motor 106 , which runs vertical conveyor assembly 102 , via lines 262 and 264 that form a hydrostatic loop. Pump 260 is controller/actuated via joystick 200 as follows. Line 266 runs through on/off switch 268 and combine speed potentiometer 270 (actuated by joystick 200 ) to servo controller 272 , which in turn is connected via line 274 to servo actuator 276 that is connected to pump 260 via line 278 for moving the swash plate of pump 260 to control the speed and direction of vertical conveyor assembly 102 via motor 106 . Line 280 runs through on-off switch 282 and unload speed potentiometer 284 to servo controller 272 (also actuated by joystick 200 ). Now, line on/off switch 268 is on (and switch 282 off) when combine 10 is not in an unloading mode, i.e., the combine is idle or harvesting grain. Switch 282 is turned on (and switch 268 off) when the operator desires to off-load grain from combine 10 . In this manner, the operator can control the speed of vertical conveyor assembly 102 via motor 106 . It will be appreciated that the function of switches 268 and 282 could be combined into a single switch unit.
[0082] When the operator desires to off-load grain from grain bin 28 , the operator also needs to control drag paddles 114 - 1116 and belt 140 . This is accomplished via on/off switch 281 (controlled by joystick 200 ) in line 283 that runs to solenoid-operated valve 284 that is disposed in line 286 . Valve 284 is actuated by pump 288 that is powered by engine 256 via line 290 . Now, line 286 from valve 284 runs to hydraulic motor 164 , which runs belt 140 , with the oil in line 286 returning to tank 292 . On/off switch 294 (also controlled by joystick 200 ) in line 295 runs to solenoid-operated valve 293 that is disposed in line 291 that branches from line 286 . Line 291 runs to hydraulic motor 118 that runs drag paddles 114 - 116 , with the oil returning to tank 292 . At this point in the description it should be noted that reservoir 224 is notated on the drawings as the reservoir for all hydraulic fluid circuits. Obviously, additional reservoirs could be used as is necessary, desirable, or convenient.
[0083] The novel airbag suspension system now will be described with specific reference to FIGS. 21 - 23 for an endless track system; although, such airbag suspension system can be adapted for tired wheels (see FIGS. 24 - 27 and the description thereof) and for a variety of articulated vehicles (e.g., other farm vehicles, earth moving equipment (bull dozers, excavators, cranes), buses, mining equipment, etc.) in addition to combines. Endless track system 298 generally includes endless metallic sectioned or rubber traction belt 30 is seen to be mounted around drive wheel 300 (wheel and hydraulic motor assembly) and idler wheel 302 . Additional intermediate idler wheels 304 - 312 are conventional in use, location, and function, and generally ensure contact of track 30 with the ground. Track system 298 is connected to frame member 314 of grain bin 28 (see FIG. 12) by stub axle 316 . Another endless track system 296 (see FIG. 23) is disposed opposite track system 298 , but will not be described in detail herein as it is a mirror image of track system 298 . Track system 296 is supported by frame 315 as seen in FIG. 12.
[0084] Each track system 296 / 298 has a pair of airbag suspension systems, e.g., 318 and 320 airbag systems (nominal rating of, e.g., 10,000 pounds) for track system 298 . Referring specifically to airbag system 320 , airbag 322 will be seen to be retained by upper plate member 324 that is connected to frame member 314 and rests on lower plate assembly 326 . Lower plate assembly 326 is connected to walking beam 328 , which is supported by stub axle 316 . Lower plate assembly 326 has a pair of upstanding forward and rearward members, 330 and 332 . Each upstanding member 330 / 332 has a race or slot in which rides a cam follower, e.g., cam follower 334 for upstanding member 330 . Cam follower 334 (and the other cams not visible in the drawings) are connected to upper plate member 324 are free to move vertically, but are restrained from moving horizontally. Thus, the cam followers dramatically reduce the large moment in the axle caused by the tracks sliding as combine 10 turns. Note should be taken that while stub axle 316 can be located at the longitudinal center of grain bin 28 , it may be advantageous to locate it forward of such center of gravity so that grain bin 28 always is lifting up on joint 22 . Also, walking beam 328 with its mounting only by stub axle 316 permits about a 12 inch rise and fall of each of its ends, i.e., wheels 300 and 302 can move ±12 inches to accommodate uneven terrain.
[0085] The same type of airbag suspension system can be adapted for tired wheels as was described for tracked wheels. Reference is made to FIG. 24 in this regard whereat articulated combine 350 is shown to have its rearward unit 352 supported by tired wheels 354 and 356 on one side, and on the other side by tired wheels 358 and 360 (see also FIGS. 25 and 26). Each tired wheel 354 / 356 / 358 / 360 is separately powered by a hydraulic motor 362 / 364 / 366 / 368 , respectively. Each forward tired wheel also is designed to be turned about 15° by a hydraulic cylinder arrangement as seen in FIG. 26 wherein cylinder 394 is seen connected from beam 384 to knuckle 396 for tired wheel 358 and cylinder 397 is seen connected from beam 382 to knuckle 398 . Cylinders 394 and 397 are hydraulically actuated and can be integrated into the steering system of combine 10 .
[0086] Tired wheels 356 and 358 are joined together by tie rod assembly 391 , which connects knuckle 396 with knuckle 398 . Tie rod assembly 391 passes through grain bin 28 at about its center, that is, where beams 382 and 384 are attached to axles 378 and 380 , respectively, in order to minimize the affect that the ups and downs that tired wheels 356 and 358 would generate as combine 10 traversed over uneven ground. Finally, spring assemblies 393 and 395 are mounted in associated with tired wheels 360 and 354 , respectively, and bias tired wheels 360 and 354 to a neutral or straight-ahead configuration. Tired wheels 360 and 354 are permitted to rotate slightly during a turn of combine 10 and spring assemblies 393 and 395 return the wheels to a straight-ahead position.
[0087] The reason for permitting rear tired wheels 354 and 360 to “free-wheel” rotate slightly during a turning of front tired wheels 356 and 358 is due to the geometry of turning an articulated vehicle. This can be seen by referring to FIG. 28 wherein an overhead simplified schematic of combine 350 is seen to include forward unit 351 , having one set of wheels, and rearward unit 352 , have two pairs of wheels. Now, during a turn of articulated combine 350 , each set of wheels must be on an arc that meets at center 502 of the radius of the turn. The corresponding radii for each set of wheels are identified by radius 504 for the wheels of forward unit 351 , radius 506 for tired wheel 358 , radius 508 for tired wheel 356 , radius 510 for tired wheel 360 , and radius 512 for tired wheel 354 . One consequence of the turning geometry is permitting rear tired wheels 354 and 360 to rotate slightly to conform to the turning radius, with spring assemblies 393 and 395 biasing them back into a straight position. Another consequence is that front tired wheels 356 and 358 can be turned along the same radius and still an acceptable turning scheme would be present; although, their radii are slightly different. Structuring a steering control system, then, accommodates the turning geometry illustrated in FIG. 28.
[0088] The airbag suspension system still is used; albeit in a slightly modified condition. That is, airbags 370 / 372 / 374 / 376 are retained by frames and utilize cam follower assemblies, 386 , 388 , 390 , and 392 , as described above. Stub axles 378 and 380 support walking beams 382 and 384 , respectively, which in turn support the airbag assemblies. Thus, each tired wheel 354 / 3561358 / 360 has the ability to rise and fall, for example, ±12 inches, to accommodate uneven terrain. FIG. 27 illustrates such construction in greater detail and taken in conjunction with FIG. 26. The remainder of operation of articulated combine 350 is the same as described above with respect to articulated combine 10 .
[0089] Now, with respect to steering and controlling articulated combine 10 , several unique problems are encountered. Prior art articulated vehicles typically use hydraulic cylinders mounted across the articulation joint to produce steering force. The cylinders are controlled by a rotary valve mechanically connected to a steering wheel that is positioned by the operator to achieve the desired turn or vehicle direction. This system is used primarily on wheeled (tired) vehicles that have one axle in front of the joint and one behind the joint, such as an agricultural tractor; or two axles behind the joint, such as a mining truck. Typically, the wheels on the axle, which are powered, are connected together and receive power from a mechanical differential. The differential permits a speed difference to be created between the two tired wheels which speed difference is required to turn with a reasonable amount of force from the articulation cylinders. To initiate a turn in such an articulated vehicle, its also is necessary to slide or rotate the portion of the tires that are in contact with the ground or supporting surface. This generally is feasible since the contact patch or portion of the tire diameter in contact with the supporting surface generally is relatively small with respect to the diameter and width of the tires. Such tire sliding or rotating usually can be accomplished with a reasonable amount of force from the steering cylinders at the articulation joint.
[0090] In an articulated combine wherein the rear module is supported by endless tracks powered by individual motors, such as is disclosed in application Ser. No. 09/210,331, cited above, the steering forces are quite different from the tired vehicle just described. The endless tracks provide a much larger contact patch than do tires and, therefore, a much higher resistance to sliding or rotating them is encountered when a turn is initiated. The contact patch area also is elongated, which further increases the force required from the articulation cylinders to initiate a vehicle turn and to recover from a turn, which maneuver also requires sliding of the tracks laterally to position the vehicle in a straight alignment.
[0091] The steering forces are increased further when individual motors are used to power the tracks, rather than a single motor and a mechanical differential to interconnect the two tracks. When individual motors on each track are used, such motors typically receive hydraulic power from a common supply, whether such supply is one pump or two pumps that are interconnected at their output ports. The common supply is necessary in a conventional system to ensure that the motors will share the propulsion load since they are mechanically interconnected by the supporting surface under the vehicle. The common supply provides the same pressure to all motors, which means that each motor will produce the same torque or thrust when the system is in equilibrium and the vehicle is moving in a straight line. In order to initiate a turn, the steering cylinders must provide sufficient force to change the arc of travel of the tracks and establish an inside track and an outside track relationship that establishes a speed differential between the two tracks. The cylinders must overcome the natural tendency of the motors to run at the same speed and to share equally the tractive effort required to move the vehicle. The cylinders must force an articulation angle that forces a portion of the tractive load to move to the inside track, which causes the pressure to go down in the outside track due to its mandated increase in speed. Hydraulic fluid flow to the outside track motor increases immediately following the path of least resistance until the pressure in the two motors equalizes. This process occurs any time the articulation angle changes during a turn of the vehicle. The steering cylinders, therefore, must not only have sufficient force to slide or rotate the tracks, but also to create a backpressure differential between the two motors. The motors, thus, are resisting both the initiation of a turn and a recovery from a turn.
[0092] The described problem can be reduced by using the differential steering techniques in conjunction with articulation cylinders as disclosed in application Ser. No. 091210,331, cited above. An implementation of such improved technique is described below in connection with FIG. 29.
System Elements
[0093] A power source, which typically is an internal combustion engine disposed in forward unit 12 and which drives hydraulic pumps, which in turn function as a controlled source of power for hydraulic motors and cylinders.
[0094] A support and tractive means on the front unit (e.g., wheel pair 20 ) powered by a hydraulic motor driving through a mechanical differential; although, use of individually driven tracks and tires can be used.
[0095] An articulation joint (e.g., articulation joint assembly 22 ) that includes at least one articulation cylinder and rod assembly (e.g., hydraulic cylinder 46 or 48 ) to provide turning force wherein the cylinder is powered by a steering valve directing the flow from a hydraulic pump. The steering valve is controlled by the operator using a steering device, such as a wheel, or can be controlled by an automatic guidance system.
[0096] A support and tractive means for rearward unit 14 (e.g., endless track assembly 298 ). Usually, there are two such track assemblies separately and independently powered by individual hydraulic motors, which receive power from a pair of hydraulic pumps, each dedicated to a single hydraulic motor. Each motor includes a transducer or sensor that measures the rotational speed of the motor and provides that information to a control system.
[0097] A programmable controller (e.g., CPU), which receives steering and propulsion information from measurement transducers, performs preprogrammed or adaptive logic functions, and directs propulsion and steering elements to implement the vehicle maneuvers commanded by the operator or automatic guidance system.
[0098] An actuator, which receives commands form the programmable controllers and adjusts the output of the hydraulic pumps powering endless track assembly 298 (and a similar assembly on the other side of rearward unit 14 ) to cause the motors to execute the operator's desired vehicle maneuvers. These actuators typically are digital stepping motors that are adjusting the pump mechanism, which sets its output. In a typical hydrostatic pump, this mechanism is called a swash plate, which sets the stroke of the pistons that determines the output flow of the pump.
System Characteristics
[0099] Motor speed is determined by the oil flow rate from the pump.
[0100] Motor torque is determined by the pressure applied to it up to the setting on the relief valve, which opens at a preset pressure and allows hydraulic fluid to bypass the motor and flow back to the reservoir.
[0101] The load the motor is seeing at any point in time determines the pressure in the hydrostatic pump/motor loop. The swash plate in the pump is establishing a flow rate to the motor. The pump will attempt to always maintain that flow rate and the pressure rises or subsides as needed to keep the motor rotating at a speed to accept that flow.
[0102] It is, therefore, possible to make multiple motors load share or accept a disproportionate share of the total system load by controlling the pressure of the hydraulic fluid flowing to them. This assumes that traction will allow the load share or shift to occur, which dictates a speed limiting control loop since the individual pumps are not cross-connected. If the motor is speeded up by increasing the pressure to it in order for the motor to take on a greater load and the track powered by such motor cannot achieve sufficient traction, the motor will overspeed. The only controllable variable in the pump is flow by changing the swash plate. However, motor pressure/torque/speed can be controlled, assuming sufficient traction is available and the motor is sized adequately to overcome the load placed on it, by controlling the flow of hydraulic fluid the pump is trying to force through it.
System Objectives
[0103] To cause the motors to share the forward or reverse propulsion load within ±5% when the steering load on the articulation cylinders is less than a defined amount, say, 1,000 psi.
[0104] To assist the articulation cylinders to execute a turn whenever the cylinder pressure in either direction goes above 1,000 psi. Note: 1,000 psi is exemplary, but based upon results of testing the articulated tracked combine disclosed herein. Such figure may vary once further acceleration or starting on grade testing is undertaken. In this situation, the pressure reference may not be as stable as speed and likely will change with the load.
[0105] The foregoing system elements, characteristics, and objectives are embodied in FIG. 29. Specifically, inputs to micro-controller 400 include left steering pressure signal 402 and right steering pressure signal 404 from steering valve 406 , which is actuated by the operator rotating steering wheel 408 . Signals 402 / 404 also are fed to left articulation cylinder 46 and right articulation cylinder 48 with lines 410 and 412 supplying the necessary interconnection between cylinders 46 / 48 and lines 410 / 412 . Such interconnection is the primary steering mechanism for articulated combine 10 .
[0106] The operator indicates the desired speed of combine 10 through lever 414 which is connected by line 416 to front axle pump 418 which drives front motor drive 420 . Lines 422 and 424 interconnect pump 418 and motor 420 with lines 426 and 428 providing two more inputs to controller 400 . Potentiometer 430 provides a reference signal via line 432 to controller 400 . Left track pump 434 powers left track motor 436 via lines 438 and 440 , from which signals 442 and 444 are sent to controller 400 . Line 446 provides yet another input to controller 400 from left track motor 436 . Right track pump 448 powers right track motor 450 via lines 452 and 454 , from which signals 456 and 458 are sent to controller 400 . Line 460 provides yet another input to controller 400 from right track motor 436 . Finally, controller 400 communicates with left track pump 434 via line 462 and with right track pump 448 via line 464 . All equipment is conventional in nature and design.
[0107] One condition that requires special attention for a tracked articulated combine is when the operator desires to commence movement (forward or reverse) from a standing or stop position with the steering wheel in a turning mode. Such initial turning movement requires tracks 30 / 32 to slide from rest, which requires a great amount of force/torque to overcome the consequent track friction with the ground. The above-described steering scheme can accommodate such conditions by initiating the turn with the articulation cylinders augmented by powering up only the outside track.
[0108] While combine 10 has been described as having non-steerable wheels, it should be appreciated that combine 10 can be designed to have steerable front wheels. Thus, steering of combine 10 can result from one or a combination of steerable forward unit wheels, articulation cylinders, and steerable (e.g., by speed differential or by wheel turning) rearward tracks (or tired wheels).
[0109] Finally, it should be appreciated also that some and/or all of the hydraulic motors, valves, pumps, and the like, can be replaced by pneumatic motors and associated equipment, electric motors and associated equipment, or by any other power generating device or system, so long as the design and operation remains with the precepts of the present invention.
[0110] While the invention has been described with reference to a preferred embodiment, those skilled in the art will understand that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. In this application all units are in the metric system and all amounts and percentages are by weight, unless otherwise expressly indicated. Also, all citations referred herein are expressly incorporated herein by reference.
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Broadly, one aspect of the present invention is an articulated combine having increased on-board grain storage capacity (e.g., 1,200 bushels) and which is composed of a forward unit having an operator's cab, an engine, a grain harvesting assembly, a grain transfer assembly, and being devoid of an on-board grain bin; and a rearward unit jointedly attached to the forward section and having, steerable and powered wheels, an on-board grain bin for receiving grain from the forward section grain transfer assembly, and a grain off-loading assembly. The grain transfer assembly, joint, and grain off-loading assembly and controls, form other aspects of the present invention.
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FIELD OF THE INVENTION
[0001] This invention pertains to anti-endazzlement/anti-glare shields that are positioned on vehicle rearview mirrors, and more particularly to templates for making same.
BACKGROUND OF THE INVENTION
[0002] The problem of dazzle and glare caused by the reflection of light originating from headlights and the sun from interior and exterior rearview mirrors of a vehicle has long been known and many attempts have been made to alleviate the problem.
[0003] A major source of night driving dazzle and glare from both interior and exterior rear view mirrors is from headlights of a trailing vehicle, and particularly if the vehicle has its high beams on. Modern streetlights, such as utilize sodium vapor lamps, are also a source of driving dazzle and glare from rearview mirrors at night. All motor vehicles today have an interior rearview mirror that include a manually operable mechanism for decreasing the reflectance of the mirror to compensate for such dazzle and glare. During earlier and latter daylight hours another major source of driving dazzle and glare from both interior and exterior rearview mirrors is the sun because it is low in the sky and behind the vehicle.
[0004] A variety of expensive and inexpensive methods and apparatus have been taught in the prior art to alleviate such reflected dazzle and glare from rearview mirrors. Interior rear view mirrors have a manually operable means to change the reflectance of the mirror as mentioned in the previous paragraph. Exterior rearview mirrors are not provided with such a solution to the dazzle and glare problem. The inexpensive approach to reduce dazzle and glare from an exterior rearview mirror has been to place a piece of tinted film over the mirror, but cutting a piece of such tinted film to fit a mirror is a laborious task. In addition, the tinted film often covers a portion of a mirror that a driver of a vehicle on which the rearview mirror is mounted wishes is not covered.
SUMMARY OF THE INVENTION
[0005] To alleviate the problems with prior art tinted films, I provide a tinted film having a release sheet protecting a surface of the tinted film used for self adhering, electrostatically adhering, or adhesively adhering the film to the viewing surface of a mirror, and on the exterior surface of the release sheet is printed a guide for cutting the tinted film that consists of a plurality of straight and curved lines that greatly assist a person in expeditiously cutting the film to the correct size to fit on a rearview mirror. For cuts to be made to the film for which the printed lines are not sufficient, a pin may be used to mark a series of small holes or pinpricks along the edge or near the edge of the mirror, and the film is then cut along the series of holes.
DESCRIPTION OF THE DRAWING
[0006] The invention will be better understood upon reading the following Detailed Description in conjunction with the drawing in which:
[0007] [0007]FIG. 1 shows the cutting guide printed on the exterior surface of the release sheet and that is used to quickly cut the tinted film to the correct size to fit on a rearview mirror.
DETAILED DESCRIPTION OF THE INVENTION
[0008] In accordance with the teaching of the present invention a method for quickly cutting a piece of tinted film to the correct size to fit on a rearview mirror is taught and claimed.
[0009] There are many sources for tinted and/or polarized film of different types that may be utilized with the present invention.
[0010] One such film is taught in U.S. Pat. No. 6,207,236, issued Mar. 27, 2001 to Araki et al. This patent teaches in claims a water-repellent coating film having excellent transparency, abrasion resistance, weather resistance and water repellency, and the method for producing the coating film. The tinted and/or polarized film may be a composite made up of various layers or plies.
[0011] Preferably the film is made of a plastic that has a lot of plasticizer added thereto during manufacture to make it very pliable. The resulting film has a very smooth surface that has a micro-suction cup like property that holds the film firmly against the viewing surface of a mirror on which it has been placed.
[0012] Alternatively the side of the tinted and/or polarized film that contacts the exterior rearview mirror may have a pressure sensitive adhesive coating for affixing the film to the face of the mirror. The adhesive is compatible with the material of the mirror and the film upon which it is coated to assure positive adherence of the tinted film to a mirror. For example, the adhesive may be an acrylic or urethane pressure sensitive adhesive or a polyester, because the rearview mirror is typically manufactured of glass. The pressure sensitive adhesive is initially covered by a conventional release liner which covers the adhesive until it is removed just prior to attaching the tinted film to a rearview mirror.
[0013] The pressure sensitive adhesive is laminated onto one surface of the tinted film which may be made from a polyethylene terephthalate (PET) film, or the film described in the above cited U.S. Pat. No. 6,207,236. While PET is preferred, the film layer could be a polyester or polycarbonate. The film contains a dye to provide the desired degree of tint and color and may also contain a material for absorbing ultraviolet (UV) rays. One UV absorber material for the film is 2,2′-Dihydroxy-4,4-methoxy benzophenone. Alternative compounds include other compatible members of the benzophenone family and compatible members of the benzatriazole family.
[0014] To one surface of the tinted film is affixed the layer of laminating adhesive. The laminating adhesive is a polyester resin cross-linked with an isocyanate. Alternative compositions could be acrylic pressure sensitive adhesives or uncrosslinked PET.
[0015] Alternatively, a film may be selected that is electrically charged during manufacture, has electrostatic properties, and will adhere electrostatically to the viewing surface of a mirror against which it is placed. The electrostatic cling provides reliable adherence for normal use but is easily broken when desired. A sheet of release type material is attached to the surface of the film that will be used for electrostatically attaching the film to the mirror to protect it from dust and dirt accumulating thereon until the film is ready to be used. Coated onto the surface of the tinted film opposite the layer that contacts a mirror may be a scratch resistant layer that protects the highly plasticized film. This layer serves to protect the film from damage through normal wear and tear. The preferred scratch resistant coating is a hard acrylic polymer. The term, “hard,” does not necessarily denote stiffness but refers to a surface that is not easily marred. Other compositions which form protective layers include urethanes and certain inorganic chemical materials.
[0016] A conventional release liner covers the surface of the film that will contact a mirror, or will cover the adhesive layer in another embodiment. On the visible side of the release layer is printed a guide or template, shown in FIG. 1, that is extremely useful for expeditiously cutting the tinted film to the correct size to fit on an exterior rearview mirror. The guide consists of a plurality of straight and curved lines that greatly assist a person in determining how to cut the tinted film. Also printed on the visible side of the release layer are directions, not shown in FIG. 1, on how to use the guide/template.
[0017] Shown in FIG. 1 are a series of semicircular arcs 10 ranging from two inches to eight inches. There are also a series of spaced parallel lines 11 used to measure rectangular sides of mirrors. A person using the template will use the semicircular arcs to measure the radius of a circular mirror, or the radius of the end of an elongated mirror with semicircular ends and can cut along the appropriate semicircle. The straight lines are then cut along for straight sides of a mirror. For circular mirrors that are very common on trucks the semicircular lines are used to cut the film into a circle that fits the circular mirror. Large trucks particularly utilize combinations of rectangular mirrors and round mirrors. Sometimes only a half circle will be cut and affixed to the upper half of a circular mirror to protect from sun dazzle and glare.
[0018] The straight and semicircular arc lines may be insufficient in some instances to complete cutting a piece of film to fit a specific mirror. In such instances, after the film has been cut as much as possible using the lines, the film may be placed up against the mirror and a pin used to make a series of pinpricks in the film to mark the edge of the mirror or, preferably, a line near the edge of the mirror. The film is them removed and scissors are used to cut along the pin pricks to complete cutting the film to fit the mirror. The release layer is then removed and the film is attached to the mirror.
[0019] When covering, for example, a circular mirror, rather than cutting and mounting a single circular piece of tinted film on the mirror, a user may wish to cut two semi-circular pieces of film and place them side-by-side on the mirror with the straight edges being adjacent to each other and horizontal to the ground. One or the other of the two pieces may be individually removed as desired. In addition, this should be done when placing film on a convex circular mirror to avoid wrinkling of the film.
[0020] While what has been the described herein is the preferred embodiment of the invention, it should be understood that one skilled in the art may make numerous changes without departing from the spirit and scope of the invention. For example, the tinted film may also be of a type that blocks ultra-violet rays from passing through the film.
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A template is disclosed for use in measuring and cutting a tinted film for attachment to a mirror to reduce dazzle and glare.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to tamper proof containers, and more particularly pertains to a new and improved tamper proof dispensing apparatus which facilitates the singular dispensing of medication containers.
2. Description of the Prior Art
In recent years, there has been a considerable amount of publicity regarding tampering with medicament containers on store shelves. In a number of cases such containers have had their contents poisoned and have then been resealed and replaced on store shelves for distribution to the public. As the result of several deaths, a large interest has developed towards the manufacture of medicament containers which are substantially tamper proof. These tamper proof containers are designed to be either substantially difficult to open or to provide an indication to a purchaser that such an undesired opening has occurred. It appears that all such efforts at tamper proofing medicament containers has centered around the sealing of the containers per se, and no efforts have been expended towards developing larger tamper proof dispensers which would protectively retain and dispense the smaller medicament containers.
With respect to the construction of dispensers now known in the prior art which might be adapted for use as a tamper proof container dispensers, a number of such dispensers have been developed wherein the contents thereof are normally inaccessible until dispensed by some type of spring biasing means. For example, reference is made to U.S. Pat. No. 926,316, which issued to A. Cairns on June 29, 1909. The Cairns device comprises a match box having a plurality of matches contained therein with such matches being dispensable one at a time by means of a manually operable spring ejection mechanism. Those matches not ejected are otherwise inaccessible. Another patent of interest is U.S. Pat. No. 2,960,259, which issued to A. Aveni on Nov. 15, 1960. The dispenser shown in this patent utilizes spring means to effect the ejectment of pills, one at a time, from a dispenser with the pills remaining therein being substantially inaccessible. However, the construction of the dispenser is complex and accordingly, it would most likely be too expensive to commercially manufacture and market.
U.S. Pat. No. 3,724,715, which issued to N. Auriemma on Apr. 3, 1973, discloses a larger scale dispenser designed to retain and individually dispense a plurality of material holding containers. Spring means are utilized to eject the material holding containers, one at a time, and an expanding crown device flexibly holds and guides a container as it is removed from the dispenser system. However, the construction of this assembly is also substantially complex and is not designed in a tamper proof manner.
Accordingly, it can be appreciated that there exists a continuing need for new and improved tamper proof dispensing systems which may be easily and inexpensively manufactured and which would reliably permit dispensing of medicament containers to the consuming public. In this respect, the present invention substantially fulfills this need.
SUMMARY OF THE INVENTION
In view of the foregoing disadvantages inherent in the known types of tamper proof dispensers now present in the prior art, the present invention provides an improved tamper proof dispensing construction wherein a plurality of non-tamper proof medicament containers or the like can be contained therein in a tamper proof manner and can be selectively dispensed to the consuming public as needed. As such, the general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new and improved tamper proof dispensing assembly which has all the advantages of the prior art tamper proof dispensing assemblies and none of the disadvantages.
To attain this, the present invention is directed to the construction of a factory sealed container in which a plurality of non-tamper proof material holding boxes or bottles may be retained. A spring biasing means facilitates a positioning of a single box or bottle proximate a dispensing slot formed in the container, and a manually actuable mechanism than permits the singular dispensing of such a box or bottle from the container when desired. Immediately upon the dispensing of a box or bottle from the container, the spring means moves another box or bottle into the dispensing slot position so as to prevent the reinsertion of the removed unit. As such, once a unit is removed from the tamper proof dispenser it cannot be reinserted therein. Accordingly, the consuming public is cautioned to purchase only those material holding containers which have not yet been removed from the primary dispensing assembly. The embodiments of the invention can be constructed to hole either boxes or bottles, as desired, and can be either totally factory sealed, so as to be disposed of after all bottles or boxes contained therein have been removed, or a lockable lid assembly can be provided to allow a refilling of the main container as needed.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. Those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, method and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Further, the purpose of the foregoing abstract is to enable the U.S. Patent and Trademark Office and the public generally, and especially the scientists, engineers and practitioners in the art who are not familiar with patent or legal terms or phraseology, to determine quickly from a cursory inspection the nature and essence of the technical disclosure of the application. The abstract is neither intended to define the invention of the application, which is measured by the claims, nor is it intended to be limiting as to the scope of the invention in any way.
It is therefore an object of the present invention to provide a new and improved tamper proof dispenser which has all the advantages of the prior art tamper proof dispensers and none of the disadvantages.
It is another object of the present invention to provide a new and improved tamper proof dispenser which may be easily and efficiently manufactured and marketed.
It is a further object of the present invention to provide a new and improved tamper proof dispenser which is of a durable and reliable construction.
An even further object of the present invention is to provide a new and improved tamper proof dispenser which is susceptible of a low cost of manufacture with regard to both materials and labor, and which accordingly is then susceptible of low prices of sale to the consuming public, thereby making such tamper proof dispensers economically available to the buying public.
Still yet another object of the present invention is to provide a new and improved tamper proof dispenser which provides in the apparatuses and methods of the prior art some of the advantages thereof, while simultaneously overcoming some of the disadvantages normally associated therewith.
Still another object of the present invention is to provide a new and improved tamper proof dispenser which eliminates the need for providing specialized tamper proof arrangements on marketable material holding containers.
Yet another object of the present invention is to provide a new and improved tamper proof dispenser which substantially promotes the safe dispensing of medicaments and other materials to the consuming public.
These together with other objects of the invention, along with the various features of novelty which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated preferred embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. such description makes reference to the annexed drawings wherein:
FIG. 1 is a perspective view of a first embodiment of tamper proof dispenser comprising the present invention.
FIG. 2 is a perspective view of a slightly modified form of the first embodiment of the invention.
FIG. 3 is a side elevation view, partly in cross section, illustrating the internal operable components of the first embodiment of the invention.
FIG. 4 is a perspective view of a second embodiment of the invention.
FIG. 5 is a perspective view of a slightly modified form of the second embodiment of the invention.
FIG. 6 is a side elevation view, partly in cross section, illustrating the internal construction of the second embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference now to the drawings, and in particular to FIGS. 1 and 2 thereof, a new and improved tamper proof dispenser embodying the principles and concepts of the present invention and generally designated by the reference numeral 10 will be described.
More specifically, it will be noted that the dispenser 10, in a first embodiment thereof, may essentially comprise a completely sealed rectangularly-shaped contained 12 in which a plurality of material holding containers 14 may be retained. As shown in FIG. 1, the container 12 may be of a factory sealed construction so as to be unopenable and unrefillable with containers 14. FIG. 2 illustrates an embodiment of the invention wherein it is provided with a topmost hingedly connected lid 16 so as to permit a refilling thereof with medicaments or other material holding containers 14 as needed. In this modified form of the invention, the lid 16 may be provided with a conventional locking clasp 18 in which an unillustrated lock may be inserted to prevent entry thereinto by unauthorized individuals.
Referencing FIG. 3 in conjunction with FIGS. 1 and 2, it will be observed that a plurality of the material holding containers 14 may be stacked within an interior portion of the container 12 so as to be dispensable one at a time from the dispenser. The stacked containers 14 are positioned on a movable plate 20 which is disposed in a slidable manner within the dispenser 12, and a compressible helical spring 22 serves to move the plate 20 upwardly within the dispenser as the containers 14 are removed.
A manually operable ejectment lever 24 is slidably disposed within a slot 26. As shown, the lever 24 may be retained within a recess 28 when not being utilized so as to not prevent an upward movement of the stacked containers 14. An ejectment of an individual material holding container 14 can be accomplished through a forward movement of the lever 24 within the slot 26, as best illustrated in FIG. 3, and a return of the lever to the recess 28 then allows a further container 14 to move upwardly into position so as to be dispensable through a ejectment slot 30 formed in the dispenser 12.
FIGS. 4, 5 and 6 illustrate a modified embodiment of the invention which is particularly designed for the holding and dispensing of material holding bottles 32. In this respect, this modified embodiment of the invention which is generally designated by the reference numeral 34 may also be formed as a rectangularly shaped container 36 and can include an inaccessible ejectment slot 38 formed therein. A manually actuatable lever 40 is movable within a slot 42 to effect an ejectment of a bottle 32 through the opening 38, with this lever being retained in a recess 44 formed on an interior surface of the container 36. The bottles 32 are moved upwardly towards the ejectment slot 38 by a slidable plate 46. The plate 46 is moved upwardly within the dispenser 36 by a compressed helical spring 48 in a manner similar to that illustrated with respect to the first embodiment 10 of the invention.
As shown in FIG. 5, the dispenser 36 may be provided with a hingedly connected openable lid 50 having a conventional locking clasp 52 attached thereto, thereby to allow a refilling of the dispenser when needed, or alternatively, as shown in FIG. 4, a totally sealed construction may be provided. In this latter construction, the dispenser 36 would be factory sealed and would be discarded after all of the material holding bottles 32 have been dispensed therefrom. To further facilitate the tamper proof construction of the invention, a flexible expansible crown member 54 may be fixedly secured within the opening 38. The crown member 54 would flexibly open to allow a bottle 32 to be dispensed therefrom, while preventing undesired access to an interior portion of the dispenser 36 or a reinsertion of a bottle.
As to the manner of operation and usage of the various embodiments of the invention, the same should be apparent from the above description. Accordingly, no further discussion with respect to the manner of usage and operation will be provided. In summary, it can be appreciated that a consumer should only purchase material holding containers 14, 32 after removing them from their respective dispensers 12, 36, and any such containers which have already been removed from the dispenser should be avoided inasmuch as they could have been tampered with.
With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention.
Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
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Boxes and bottles of pills and other medications are factory sealed in a tamper proof dispenser which permits the dispensing of only one bottle or box at a time. Once removed from the tamper proof container, a bottle or box cannot be repositioned in the container, while spring means are utilized to permit the singular dispensing of each bottle or box from the container.
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BACKGROUND OF THE INVENTION
This invention relates to a pressure capsule as well as a spray can which utilizes such pressure capsule.
The present invention more especially relates to a pressure capsule which prior to or during the filling of a spray can or similar is installed in the latter and offers the possibility of possibly making use of, either compressed air, or an inert gas as means of propulsion for such spray can, all of which such that a spray can is obtained which has no detrimental effect on the environment and which furthermore has the possibility and the simplicity of operation which at this moment are only to be found with spray cans with the known harmful propellants.
1. Field of the Invention
From the Belgian Pat. No. 8801131 of applicant a pressure capsule is already known which principally consists of at least two chambers of which the first is intended to be filled with a fluid under relatively high pressure and of which the second is intended to be filled with a fluid up to a pressure almost equal to the over pressure which normally exists in a spray can and which is necessary for expelling a liquid; in the wall of the first chamber a valve; in the wall of the second chamber a membrane that can command the aforementioned valve; and a removable element that in its unremoved position holds the valve closed.
With this known pressure capsule the aforementioned removable element can directly or indirectly act on the valve in order to hold this closed and preferably consists of a material meltable by little heat, all of which such that, after the aforementioned removable element is removed, the aforementioned valve is so regulated by the membrane that fluid is released from the first chamber as long as the pressure in the vicinity of the pressure capsule decreases or at least is notably lower than the pressure in the second chamber of the pressure capsule.
Although this known pressure capsule works very efficiently the present invention relates to a pressure capsule which still shows considerable additional advantages.
SUMMARY OF THE INVENTION
A first advantage of the pressure capsule according to the invention is that no removable element is necessary so that heating of the spray can, with the intention of melting away the removable element, is no longer necessary.
Another advantage of the pressure capsule according to the invention is that in the spray can, after the pressure capsule is installed therein, a specific pre-pressure is provided, preferably at least the operating pressure of the spray can, through which the aforementioned pressure capsule can remain smaller because of the fact that less pressure fluid is necessary in the pressure capsule so that consequently the material costs are also lower.
Yet another advantage of the pressure capsule according to the invention is the very great safety of a spray can equipped with such pressure capsule since, with a possible tearing, leakage or similar of the spray can, the pressure capsule automatically closes, since at that moment the pressure around the pressure capsule drops.
Another advantage of the pressure capsule according to the invention is that it is no longer necessary, which is the case with a pressure capsule with removable element, during its manufacture, to determine the correct location of the small hole that the removable element must receive, since the opening or passage of the pressure capsule which is in contact with the environment can be provided in any manner and in any place, so that a difficult orientation operation can be omitted.
Another advantage still of the pressure capsule according to the invention is that the dimensions of the aforementioned opening or passage have no importance with regard to the operation of the pressure capsule.
Yet another advantage of the pressure capsule according to the invention is ultimately that it is extremely simple to realize, either as dual chamber pressure capsule, or as single chamber pressure capsule.
The pressure capsule according to the invention which shows the aforementioned and other advantages principally consists of at least one chamber which is intended to filled with fluid under relatively high pressure; in the wall of this chamber a valve; means which can command the valve; means which hold the valve in closed position when the pressure capsule is in an atmospheric environment, on the one hand, as well as when the pressure capsule is in an environment where the pressure is equal to or greater than the operating pressure in the spray can, in other words the pressure which is necessary for the expulsion of a liquid, on the other hand; whereby the rod of the valve is attached to a membrane in the chamber, respectively to a disk shaped extremity and whereby the space between the walls, respectively between the wall and the disk shaped extremity, is in continuous connection with the environment.
BRIEF DESCRIPTION OF THE DRAWINGS
In order to show better the characteristics according to the present invention, some preferred embodiments are described hereafter, as examples and without any restrictive character with reference to the enclosed drawings in which:
FIG. 1 shows a spray can in which a pressure capsule according to the invention is utilized;
FIG. 2 shows on larger scale a section of a pressure capsule according to the invention, more especially according to line II--II in FIG. 1;
FIG. 3 shows on larger scale the part that is indicated by F3 in FIG. 2;
FIGS. 4 and 5 are similar views to that from FIG. 3 but for two other characteristic positions;
FIGS. 6 and 7 show variants of FIG. 3;
FIG. 8 shows a practical embodiment of a pressure capsule according to the invention;
FIG. 9 shows a section according to line IX--IX in FIG. 8;
FIG. 10 shows another variant of a pressure capsule according to the invention
FIG. 11 shows a top view of FIG. 10;
FIG. 12 shows a second position of FIG. 10.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1 a classic spray can 1 is shown which is filled with a liquid 2 to be dispersed and in which a pressure capsule 3 according to the invention is installed.
The pressure capsule 3, as shown in FIG. 2, can be constructed in any manner by assembling various parts by screwing, welding or similar. For simplicity the pressure capsule in FIG. 2 is however shown as being of one unit.
The pressure capsule 3 in this embodiment principally consists of two chambers, respectively 4 and 5, of which the first chamber 4 is intended to be filled with a fluid under relatively high pressure and of which the second chamber 5 is intended to be filled with a fluid under a pressure which is equal or almost equal to the over pressure which is normally applied in a spray can 1.
A valve 7 is provided in the wall 6 of the first chamber, while in the second chamber 5 a wall 8 is installed which is provided with a membrane 9 that bears a rod 10 to which the valve 7 is attached. From the preceding it follows that the walls in which, on the one hand, the valve 7 and, on the other hand, the membrane 9 are installed, are located opposite each other whereby the space 11 between the walls 6 and 8 are directly connected to the vicinity of the pressure capsule 3, in this case via a small hole 12.
In the embodiment according to FIG. 2 the chambers 4 and 5 each show an opening, respectively 13, 14, which can be closed by suitable sealing means 15, 16.
The valve 7 is in this case formed by, on the one hand, the aforementioned rod 10 which is attached by one extremity to the membrane 9, whereby this rod passes through an opening in the wall 6 and underneath shows a peripheral groove 17, which for example is produced in a diabolo shape and, on the other hand, a sealing ring 18 which is installed in the aforementioned opening in the wall 6 and which functions as seat for the valve 7.
The inner diameter of the sealing ring 18, which is produced in an elastic material, for example rubber or similar, will preferably be somewhat smaller than the outer diameter of the rod 10 whereby the sealing ring 18 is placed in the aforementioned peripheral groove 17.
According to the invention, for example via the opening 13, the first chamber 4 is filled with a fluid under high pressure, for example of the order of 30 kg/cm 2 , such as compressed air or another gas, preferably, but not necessarily, an inert gas, after which the opening 13 is sealed off with suitable means, such as by gluing, by welding, by a screw plug or similar 15.
The chamber 5 is likewise filled via the opening 14 with compressed air or another fluid up to an over pressure which is approximately equal to the desired operating pressure in the spray can 1, whereby this operating pressure is for example of the order of 3 kg/cm 2 . Once at this pressure the chamber 5 will be sealed off by means 16, such as for example by gluing, by welding, by a screw plug or similar.
The pressure capsule 3 as described above can be utilized very advantageously in a spray can 1 filled with liquid 2 in order to supply the pressure medium, in this case air, that serves to remove the liquid 2 from the spray can 1 via an ascending tube 19 and controlled through a valve 21 operatable by means of a press button 20.
For this purpose the pressure capsule 3 is installed in the spray can 1, prior to, during or after the filling of the spray can 1 with liquid 2 and prior to the installation of the cover 22 with the ascending tube 19 and the valve 21, after which according to the invention the spray can 1, such as this is the case with traditional spray cans, is brought up to operating pressure, in other words up to a pressure which is equal to or is somewhat higher than the pressure in the chamber 5.
Because of this it is achieved that the membrane 9, under influence of the pressure in the space 23 above the liquid 2, on the one hand, and the small additional pressure of the fluid in the chamber 4 at the extremity of the rod 10, on the other hand, in FIG. 2 moves upwards through which the sealing element 10 moves out of the position as shown in FIG. 3 to the position as shown in FIG. 4, with as result that compressed air or similar escapes out of the chamber 4 through the opening 12 into the space 23, all of which such that the upward pressure P on the membrane 9 increases with ultimately as result that the membrane 9 is placed in the position as shown in FIG. 5, in other words in the position whereby the valve 7 in its second position works together with the sealing ring 18 so that removal of compressed air from chamber 4 towards the space 23 is stopped.
When at this time, through the depression of the press button 20, liquid 2 is dispersed under influence of the pressure of the fluid in the chamber 23, the pressure in the space 23 will decrease until an equilibrium is reached with the pressure in chamber 5 of the pressure capsule 3, through which the membrane moves downward and the valve 7 comes into the position of FIG. 4.
It is clear that at this time compressed air escapes out of chamber 4 towards the space 23 through which the pressure P on the membrane 9 again increases so that, when the force exerted under the membrane 9 becomes greater than the force above the membrane, the latter again moves upwards in order to close off the supply of compressed air from the chamber 4 towards the chamber 23, as shown in FIG. 5.
In FIG. 6 an embodiment variant is shown whereby the valve 7 is formed by sealing elements for example in the form of a frustum of a cone, respectively 24 and 25, which can alternatively close off the opening 26 in the wall 6.
An embodiment is shown in FIG. 7 whereby the valve 7 is formed by an oblique passage 27 which can move under or above the sealing ring 18 when the valve 7 is closed, and just at the height of the sealing ring 18 when the valve 7 is opened.
An embodiment is shown in schematic manner in FIGS. 8 and 9 whereby the lower chamber 4 consists of an upper part 28 and a lower part 29 which fit together suitably and are connected to each other by gluing, welding or similar 30 and whereby the upper chamber also consists of two parts, respectively 31 and 32, which are connected to each other in suitable manner by gluing or welding 33 with insertion of the wall 8 of the membrane 9.
In this embodiment the part 31 of the chamber 5 shows as it were four small legs 34 which underneath show an inwardly directed tooth shaped projection 35 which can work together, by clipping in, behind the edge 36 of the part 28 of the chamber 4.
In this case the opening 12 is formed between the aforementioned small legs 34.
It is clear that the pressure in the chamber 5 can be formed in whatever manner and need not necessarily be built up by means of a fluid. Indeed the pressure above the membrane 9 could also be formed by a suitable spring or similar for example an elastic material such as among others a small block of foam rubber 37.
Another embodiment variant is shown in FIG. 10 which is based on a single chamber pressure capsule.
With this only the chamber 4 is provided which as with the dual chamber pressure capsule described above is filled with a fluid under relatively high pressure.
In this case the membrane 9 is replaced by a stiff disk shaped extremity 38 of the rod 10, whereby between the wall 6 of the chamber 4 and the aforementioned extremity 38 an elastic element 39 is installed, foam material, with closed cells, whereby the elasticity of the element 39, which as it were is the so-called reference pressure (to be compared to the pressure in the space 5 in the embodiment according to FIG. 2) which is present in the cells, will be chosen or determined in relation to the operating pressure in the spray can 1.
In the embodiment according to FIG. 10 a small annular block of foam material 39 is provided in which at least one groove, passage or similar 40 is made, whereby this small block 39 is attached to, on the one hand, the wall 6 and, on the other hand, the disk shaped extremity 38, for example by gluing or another attachment.
The attachment of the small block 39 and the valve could for example also be effected by extending the housing of the pressure capsule to above the aforementioned extremity as is shown in dotted line in FIGS. 10 and 12, so that the upper position of the small block 39 is determined by the presence of the ring 41.
In FIG. 10 the position of the air pressure capsule is shown when this is in an atmospheric environment. The lower part of the valve 7 closed off the chamber 4 and ring 39 is in released position, whereby the pressure of the ring 39 or similar on the disk shaped extremity 38 is approximately equal to atmospheric pressure, whereby the pressure in the closed cells of the ring 39 amounts to one bar.
When the air pressure capsule according to FIG. 10 is inserted into a spray can 1 and the latter is brought up to operating pressure, the pressure exerted on the extremity 38 will be such that the seal 10 moves into the chamber 4 whereby the disk shaped extremity 38 presses on the spring, small block of foam material or similar 39 and brings this into the position as shown in FIG. 12, whereby the valve 7 is again closed off.
When now, through the spraying of the liquid, the pressure in the spray can 1 slowly decreases, the valve 7, respectively the rod 10 with the disk shaped extremity 38, will again move upwards under influence of the expansion effect of the small block or similar 39. Because of this an amount of compressed air can escape out of the chamber 4 along the valve 7 and arrive in the space 23 in the spray can 1 so that, just as with the preceding embodiment, the pressure in the space 23 again increases until the valve 7 again closes off the space 4.
It is clear that, through the correct choice of the material for the small block 39 or similar, on the one hand, and the surface area of the disk shaped extremity 38, on the other hand, the operating pressure in the space 23 of the spray can 1 can be determined.
The present invention is in no way restricted to the embodiments described as examples and shown in the attached drawings but a pressure capsule according to the invention can be implemented in all types of forms and dimensions without departing from the scope of the present invention.
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A pressure capsule for a spray can includes a housing with a chamber disposed therein and a valve mounted within a wall of the housing, the valve is capable of being moved into an open and a closed position such that the valve is moved into the closed position when (1) the pressure capsule is placed in an atmospheric environment and (2) the pressure capsule is placed in a spray can and subjected to a pressure equal to or greater than the operating pressure of the spray can.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to wheeled luggage and more particularly to an improved handle assembly having a single handle rod of wheeled luggage.
2. Description of Related Art
Conventionally, a handle assembly of wheeled luggage has a pair of handle rods. This has the advantage of increased stability while towing luggage. However, it also consumes some precious storage space of luggage because a portion of rear is configured to receive the handle assembly. Further, more components means higher possibility of fail of luggage and higher manufacturing cost. Hence, a handle assembly having a single handle rod has been developed. Such is best illustrated in FIGS. 16 and 17. For increasing the structural strength, a handle rod H has a larger diameter. The prior art is unsatisfactory for the purpose for which the invention is concerned for the following reasons: User may feel uncomfortable by holding both a T-shaped handle grip G and a joint C between the handle grip G and a handle rod H. Also, a trouser T may interfere with one wheel while towing luggage because the handle grip G does not extend laterally enough (i.e., it is near the center of luggage). It is quite inconvenient.
Thus, it is desirable to provide a handle assembly having an improved single handle rod of wheeled luggage in order to overcome the above drawbacks of prior art.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a handle assembly having a single handle rod of wheeled luggage wherein the handle grip is extended toward and near one side of luggage for ease of holding. Also, there is no interference of user's body with wheel while towing luggage.
It is another object of the present invention to provide a handle assembly having a single handle rod of wheeled luggage wherein the handle grip is rotatable either clockwise or counterclockwise to an angle of about 180 degrees with respect to a straight line between wheels of the luggage so as to be gripped by either the right or the left hand which tows the luggage.
In one aspect of the present invention, there is provided a handle assembly of wheeled luggage comprising a handle grip extended toward and proximate either side of the luggage for eliminating an interference of a user with one of more wheels of the luggage, the handle grip including a pivot section having a first tunnel, a second tunnel within the first tunnel and having a longitudinal slit on each side surface, an upper section, a lower section, and a peripheral groove between the upper and the lower sections; a sleeve including an upper larger section having a plurality of holes on its periphery, a plurality of pegs inserted through the holes to slidingly contact the groove, a lower smaller section, and a bore through the lower smaller section; a push button assembly received in both the pivot section and the sleeve and including a push button on a top, a post extended downwardly from the push button and having a longitudinal rib on each side surface of the post being slidingly received in the slit, a lower cylindrical member having a diameter smaller than a width of the post, and a base, a recess on a bottom of the base, and an aperture inside the cylindrical member being open to the recess; a handle rod releasably secured to the sleeve; a seat releasably secured within the handle rod and including a circular flange on a top and a channel; and a spring having a top end anchored in the recess and a lower end put on the flange. In an operation the push button is operative to press to compress the spring and lower the base for disengaging from the bore, thereby enabling a rotation of the handle grip and a retraction of the handle rod.
In another aspect of the present invention, there is provided a handle assembly of wheeled luggage comprising a handle grip extended toward and proximate either side of the luggage for eliminating an interference of a user with one of more wheels of the luggage, the handle grip including a hollow bar having a space, a pivot section, a wedge having a first slanted surface, and a sliding member in the space and having a push button at one side on an opening of the hollow bar, a second slanted surface at the other opposite side engaged with the first slanted surface, and a pivot section including a tunnel having a longitudinal slit on each side surface, an upper section, a lower section, and a peripheral groove between the upper and the lower sections; a sleeve including an upper larger section having a plurality of holes on its periphery, a plurality of pegs inserted through the holes to slidingly contact the groove, a lower smaller section, and a bore through the lower smaller section; a push button assembly received in both the pivot section and the sleeve and including a push button on a top, a post on a bottom of the wedge and having a longitudinal rib on each side surface of the post being slidingly received in the slit, a lower cylindrical member having a diameter smaller than a width of the post, and a base, a recess on a bottom of the base, and an aperture inside the cylindrical member being open to the recess; a handle rod releasably secured to the sleeve; a seat releasably secured within the handle rod and including a circular flange on a top and a channel; and a spring having a top end anchored in the recess and a lower end put on the flange. In an operation the push button is operative to press push the sliding member inwardly, move the second slanted surface inwardly to press down the first slanted surface, compress the spring, and lower the base for disengaging from the bore, thereby enabling a rotation of the handle grip and a retraction of the handle rod.
The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a rear plan view of a first preferred embodiment of handle assembly having a single handle rod according to the invention;
FIG. 2 is a top plan view showing the FIG. 1 luggage being towed;
FIG. 3 is a perspective view of a second preferred embodiment of handle assembly having a single handle rod according to the invention,
FIG. 4 is an exploded perspective view of FIG. 3 handle assembly;
FIG. 5 is a partial cross-sectional view of FIG. 4;
FIG. 6 is a cross-sectional view of FIG. 3 handle assembly in a locked position;
FIG. 7 is a view similar to FIG. 6 where push button is pressed and handle assembly is in an unlocked position;
FIG. 8 is another view of FIG. 7 showing handle grip being capable of rotating;
FIG. 9 is an exploded perspective view of a third preferred embodiment of handle assembly having a single handle rod according to the invention;
FIG. 10 is a cross-sectional view of a fourth preferred embodiment of handle assembly having a single handle rod according to the invention where handle assembly is in a locked position;
FIG. 11 is a view similar to FIG. 10 where push button is pressed and handle assembly is in an unlocked position;
FIG. 12 is a side view showing a using of luggage handle constructed according to any of above preferred embodiments of the invention being towed;
FIG. 13 is a rear plan view of a second configuration of handle grip of the handle assembly according to the invention;
FIG. 14 is a rear plan view of a third configuration of handle grip of the handle assembly according to the invention;
FIG. 15 is a rear plan view of a fourth configuration of handle grip of the handle assembly according to the invention;
FIG. 16 is a rear plan view of a conventional luggage handle assembly having a single handle rod; and
FIG. 17 is a top plan view showing the FIG. 16 luggage being towed.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1 and 2, there is shown a first preferred embodiment of luggage 50 according to the invention comprising a front 51 , a rear 52 , two sides 53 and 54 , a top 57 , a bottom 58 , two wheels 55 and 56 , and a retractable handle assembly 10 which is the subject of the invention. The handle assembly 10 comprises a handle rod 15 (i.e., first sliding tube) having an upper portion and a lower portion, a handle grip 20 extended horizontally from a top of the handle rod 15 (i.e., parallel to a straight line between wheels, the top 57 , or the bottom 58 ) in a normal unused position wherein the horizontal extension length of the handle grip 20 is slightly smaller than a half of width of the top 57 .
It means that the handle grip 20 is extending horizontally from the top of the handle rod 15 almost to a side 53 of the luggage. As shown in FIG. 2, in a case that the left hand holds the handle grip 20 a sufficient distance between the side 53 and the foot F is obtained. As a result, the user's foot is prevented from being interfered with the wheel 55 while towing the luggage 50 . It is noted that the handle grip 20 may be extended toward and sufficiently proximate the right side 54 for being adapted to be gripped by the user's right hand in the other embodiment without departing from the scope and spirit of the invention.
Referring to FIGS. 3 to 8 , there is shown a second preferred embodiment of luggage 50 constricted in accordance with the invention comprising a front 51 , a rear 52 , two sides 53 and 54 , a top 57 , a bottom 58 , two wheels 55 and 56 , and a retractable handle assembly 10 extended upward from a center at a joining edge of the top 57 and the rear 52 . The handle assembly 10 is the subject of the invention and will be described in detail as follows. The handle assembly 10 comprises a handle grip 20 , a sleeve 12 , a push button assembly 11 , a first sliding tube 15 , a second sliding tube 16 , a support tube 17 , a first locking device 18 , and a second locking device 19 . Note that the components and operation of the handle assembly 10 are well known. Thus a detailed description thereof is omitted herein for the sake of brevity except those detailed below.
As shown in FIGS. 4 and 5, the handle grip 20 comprises a horizontal bar 21 having a downwardly extended hook 211 at one end, a pivot section 22 proximate the other end of the bar 21 having a circular tunnel 210 through the pivot section 22 , a square tunnel 220 within the circular tunnel 210 and having a longitudinal slit 2201 on each side surface, a large diameter section 221 on upper part of the pivot section 22 , a small diameter section 222 below the large diameter section 221 , and a peripheral groove 2220 between the large diameter section 221 and the small diameter section 222 . The push button assembly 11 is received in both the pivot section 22 and the sleeve 12 and comprises a push button 110 on a top, a post 111 extended downwardly from the push button 110 and having a square cross-section and a longitudinal rib 1110 on each side surface of the post 111 being slidingly received in the slit 2201 , a cylindrical member 112 having a diameter smaller than the width of the post 111 being extended downwardly from the post 111 , and a square base 113 , a recess 115 on a bottom of the base 113 , and a central circular aperture 114 inside the cylindrical member 112 being open to the recess 115 . The sleeve 12 comprises an upper larger section 120 having four equally spaced apart holes 1201 on its periphery, four pegs 123 inserted through holes 1201 to slidingly contact the groove 2220 , a lower smaller section 121 having two opposite holes 1210 on its periphery, and a square bore 124 through the lower smaller section 121 . The handle assembly 10 further comprises a seat 14 including a circular flange 141 on a top, a base 142 , a tunnel 143 through the base 142 , and two opposite holes 144 on its periphery open to the tunnel 143 ; and a spring 13 having a top end anchored in the recess 115 and a lower end put on the flange 141 . The first sliding tube 15 comprises two upper opposite large holes 151 , two screws 153 driven through holes 151 and holes 1210 to secure the first sliding tube 15 to the sleeve 12 , two lower opposite small holes 152 , two screws 154 driven through the holes 152 and 144 to secure the seat 14 within the first sliding tube 15 .
The assembled handle assembly 10 is shown in FIG. 6 wherein the base 113 is urged upwardly by the spring 13 to be stopped at the top edge of the bore 124 and a spring depressible locking pin 183 is inserted into one of a plurality of apertures on the second sliding tube 16 in a locked state.
Note that one characteristics of the invention is that there is no interference of user's foot F with the wheel 55 while towing the luggage 50 . This is because the handle grip 20 is extended toward and sufficiently proximate one side (e.g., the left side 53 as shown in FIG. 2) of the luggage for being adapted to be gripped by the user's left hand, thus leaving a sufficient distance between the user's foot F and the wheel 55 . It is further noted that the handle grip 20 may be extended toward and sufficiently proximate the right side 54 for being adapted to be gripped by the user's right hand in the other embodiment without departing from the scope and spirit of the invention.
Referring to FIGS. 7 and 8 specifically, an operation of the invention will now be described in detail as follows: First, a user can press the push button 110 to compress the spring 13 . At the same time, the base 113 is lowered to disengage from the top edge of the bore 124 . Also, the locking pin 183 is unlocked. Hence, user can then rotate clockwise or counterclockwise the handle grip 20 per operation until a desired angle of the handle grip 20 with respect to the luggage 50 (i.e., straight line between wheels) is reached (i.e., a position where the user feels comfortable when gripping the handle grip 20 for towing luggage). Note that the handle grip 20 is adapted to rotate 90 degrees per operation because the elements 111 , 220 , 124 , and 113 are square (see FIGS. 4 and 5 ). In another embodiment, the handle grip 20 is adapted to rotate 45 degrees per operation since the elements 111 , 220 , 124 , and 113 are made as octagons. In still another embodiment, the handle grip 20 is adapted to rotate 30 degrees per operation since the elements 111 , 220 , 124 , and 113 are made as ones having twelve equal sides.
Referring to FIG. 9, there is shown a third preferred embodiment of handle assembly 10 according to the invention. The differences between the second and the third embodiments are that four pegs 123 of the second embodiment are replaced by two elongate members 123 A each having a circular (or square) cross-section; and four equally spaced apart holes 1201 are replaced by four spaced apart holes 1201 A while having shapes different from that of the holes 1201 .
Referring to FIGS. 10 and 11 there is shown a fourth preferred embodiment of handle assembly 10 according to the invention. The differences between the second and the fourth embodiments are that the handle grip 20 B is hollow and having a space 214 B, the push button assembly 11 is replaced by a push button assembly 11 A including a wedge 110 A on top of the post 111 having a slanted surface 114 A, and a sliding member 11 B in the space 214 B and having a horizontal push button 110 B at one side on the opening of the handle grip 20 b and a slanted surface 114 B at the other opposite side engaged with the slanged surface 114 A.
Referring to FIG. 11 specifically, an operation of the fourth embodiment of the invention will now be described in detail as follows: First, a user can press the push button 110 B to push the sliding member 11 B inwardly. At the same time, the slanted surface 114 B moves inwardly to press down the slanted surface 114 A. As a result, the spring 13 is compressed to energize, the base 113 is lowered to disengage from the top edge of the bore 124 , and the locking pin 183 is unlocked. Similarly, the user can then rotate clockwise or counterclockwise the handle grip 20 B until a desired angle of the handle grip 20 B with respect to the luggage 50 is reached.
As state above, the characteristics of the invention is that the handle grip is extended toward and sufficiently proximate one side of the luggage for being adapted to be gripped by the user's either hand, thus leaving a sufficient distance between the user's foot and either wheel for preventing a possible interference of user's foot with the wheel from occurring while towing the luggage. Additionally, the invention comprises the characteristics by referring to FIG. 12 . As shown, handle grip 20 is rotated clockwise or counterclockwise to an about 90-degree angle with respect to the luggage 50 , i.e., with respect to the straight line between wheels of the luggage 50 . At this position, the user can also smoothly tow the luggage 50 by holding the handle grip 20 . Note that above mechanism of the rotation of the handle grip 20 with respect to the luggage 50 may be eliminated in any of other embodiments in a suitable scheme (i.e., the handle grip 20 is fixed on the handle assembly 10 ).
Referring to FIGS. 13 to 15 , there are shown three different configurations of the handle grip 20 . As shown in FIG. 13, a handle grip 20 C has an arcuate inner edge 208 of a joint between itself and the first sliding tube 15 . The handle grip 20 C of handle assembly 10 C includes a push button 110 C. As shown in FIG. 14, a handle grip 20 D of handle assembly 10 D has an arcuate joint between itself and the first sliding tube 15 and a push button 110 D is disposed on a top of the arcuate joint. As shown in FIG. 15, a handle grip 20 E has an arcuate joint between itself and the first sliding tube 15 and an arcuate hooked end having a construction similar to that of the arcuate joint. The handle grip 20 E of handle assembly 10 E includes a push button 110 E.
While the invention herein disclosed has been described by means of specific embodiments, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope and spirit of the invention set forth in the claims.
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A handle assembly having a single handle rod of wheeled luggage is provided. The handle grip is extended toward and proximate either side of luggage for ease of holding. Also, there is no interference of user's body with wheel while towing luggage. Moreover, the handle grip is capable of being disposed either parallel or perpendicular with respect to a straight line between wheels of the luggage by rotating either clockwise or counterclockwise for ease of being gripped by either hand which tows the luggage.
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BACKGROUND OF THE INVENTION
[0001] The invention relates generally to the mixing of fluid flow streams and, more particularly to the injection of a primary fluid into a secondary fluid cross-stream, as found in, but not limited to, jet engine combustion chambers, jet engine bleed-air discharge nozzles, and jet-engine thrust vectoring nozzles.
[0002] A fluid jet injected essentially normally to a fluid cross-stream is an important phenomenon that is ubiquitous in industrial processes involving mixing and dispersion of one fluid stream into another. For example, the “jet in cross-flow” phenomenon, as it is commonly called, dictates the efficiency of the mixing process between different gases in a jet combustor, controlling the rates of chemical reactions, NO x and soot formation, and unwanted temperature non-uniformity of gases impinging on the turbine blades.
[0003] The jet-in-cross-flow phenomenon is also present at the discharge port of high temperature compressor bleed-air into the fan steam of jet engines, as well as in fuel injector nozzles on afterburners and in fluidic thrust-vectoring devices.
[0004] Herein, we define as “primary fluid” the fluid of the injected jet, and as “secondary fluid” the fluid of the cross-stream. The two main characteristics of the jet-in-cross-flow phenomenon are:
[0005] a) the penetration depth of the primary fluid plume into the secondary fluid stream, and
[0006] b) the rate of dispersion and mixing of the primary fluid plume into the secondary fluid stream.
[0007] Comprehensive parametric studies of multiple round jets to optimize crossflow mixing performance have been reported since the early '70s, the most general and applicable to subsonic crossflow mixing in a confined duct being reported by J. D. Holdeman at NASA (Holdeman, J. D., “Mixing of Multiple Jets with a Confined Subsonic Crossflow”, Prog. Energy Combust. Sci., Vol. 19, pp. 31-70, 1993.). Those studies, both numerical and experimental, developed correlating expression to optimize gas turbine combustor pattern factor. The primary result was that the jet-to-mainstream momentum-flux ratio was the most significant flow variable and that mixing was similar, independent of orifice diameter, when the orifice spacing and the square-root of the momentum-flux were inversely proportional. More recent efforts at Darmstadt (Doerr, Th., Blomeyer, M. M., and Hennecke, D. K., “Optimization of Multiple Jets Mixing with a Confined Crossflow”, ASME -96- GT -453, 1996 and Blomeyer, M. M., Krautkremer, B. H., Hennecke, D. K., “Optimization of Mixing for Two-sided Injection from Opposed Rows of Staggered Jets into a Confined Crossflow”, ASME -96- GT -453, 1996.) further studied the optimization of round jet configurations for gas turbine applications.
[0008] Although optimized round jets provide control of pattern factor, reduction of NO x emissions could be attained by more rapid mixing in the combustion chamber. Since axisymmetric coflow configurations on non-circular orifices, such as an ellipse, had been shown to increase entrainment relative to a circular jet (Ho, C-M and Gutmark, E, “Vortex Induction and Mass Entrainment in a Small-Aspect-Ration Elliptic Jet”, J. Fluid Mech., Vol. 179, pp. 383-405, 1987 and Gutmark, E. J. and Grinstein, F. F., “Flow Control with Noncircular Jets”, Annual Rev Fluid Mech., Vol. 11, pp. 239-272, 1999.), similar orifices were considered for NO x reduction in crossflow configurations during NASA's High Speed Research program in the early '90s. Liscinsky (Liscinsky, D. S., True, B., and Holdeman, J. D., “Mixing Characteristics of Directly Opposed Rows of Jets Injected Normal to a Crossflow in a Rectangular Duct”, AIAA -94-0218, 1994.) and Bain (Bain, D. B., Smith, C. E., and Holdeman, J. D., “CFD Assessment of Orifice Aspect Ratio and Mass Flow Ration on Jet Mixing in Rectangular Ducts”, AIAA -94-0218, 1994.) using parallel-sided orifices (squares, rectangles and round-ended slots) launched an investigation to improve upon the mixing performance of round jets. Optimizing correlations were developed but a significant enhancement in mixing relative to round holes was not achieved. The slots were also rotated relative to the mainstream to control jet trajectory but mixing enhancement was not observed for optimized configurations. Concurrent investigations in cylindrical ducts were performed experimentally and numerically by Sowa (Sowa, W. A., Kroll, J. T., and Samuelsen, G. S., “Optimization of Orifice Geometry for Crossflow Mixing in a Cylindrical Duct”, AIAA -94-0219, 1994.) and numerically by Oeschle (Oechsle, V. L., Mongia, H. C., and Holdeman, J. D., “An Analytical Study of Jet Mixing in a Cylindrical Duct”, AIAa -93-2043, 1993.) also without significant mixing improvement relative to circular jets.
[0009] Detailed single jet studies of symmetric noncircular orifice shapes in crossflow were also performed in the late 90s (Liscinsky, D. S., True, B., and Holdeman, J. D., “Crossflow Mixing of Noncircular Jets”, Journal of Propulsion and Power, Vol. 12, No. 2, pp. 225-230, 1996 and Zamn, KBMQ, “Effect of Delta Tabs on Mixing and Axis Switching in Jets from Axisymmetric Nozzles”, AIAA -94-0186, 1994.). These investigations also included the use of tabs placed at the nozzle exit as vortex generators. Azimuthal non-uniformity at the jet inlet is naturally unstable and introduces streamwise vorticity which increases entrainment for axisymmetric flows, however in a crossflow configuration the vorticity field is dominated by the bending imposed by the mainstream. The vorticity generated by the initial jet condition was found to be insignificant and appreciable mixing enhancement relative to a circular jet was not observed.
[0010] In summary, a round orifice is the most commonly used shape from which the primary fluid emanates, leading to a jet of essentially cylindrical shape in the vicinity of the orifice. This cylindrical shape is rapidly bent by the secondary cross-stream into a plume oriented with the cross-stream direction. Prior-art investigations have been directed at discovering improved orifice shapes in the hope of passively improving either or both of the plum penetration and dispersion and mixing. While slanted slots have provided some reduction in penetration depth, no shapes have been reported that offer significant improvements over the round orifice shape. The lack of a mechanism for the control of plume penetration depth that is independent of the exit jet velocity is a shortcoming that forces compromises into the design of industrial systems.
[0011] Furthermore, the downstream development of the plume from prior-art non-circular orifices is similar to that of the plume form the circular orifice. In particular, both circular and non-circular cases generated a plume characterized by a cross-sectional area of kidney-like form containing two counter-rotating vortices oriented parallel to the secondary-fluid stream direction. Far from the plume, the velocity induced by one vortex of this vortex pair is essentially cancelled by the other counter-rotating vortex of the pair. Consequently, when multiple plumes are present, the counter-rotating vortices produce a weak interaction between neighboring plumes emitted from near-by orifices, leading to relatively weak overall dispersion of the primary fluid.
[0012] It is thus desirable to have an orifice shape that leads to a strong control of primary-fluid plume penetration independent of exit jet velocity, thus allowing authoritative placement of the jet plume at a desired, predetermined depth into the secondary steam. It is also desirable to have an orifice shape leading to a plume containing a single, rather than a pair, of vortices, that allows stronger interaction between neighboring plumes.
[0013] Objects of the current invention are thus to:
[0014] 1) provide a geometry for the primary-fluid orifice that leads to a strong control authority over the primary fluid plume penetration depth into the secondary stream, the penetration control being independent of exit jet velocity, and
[0015] 2) provide a geometry for the primary-fluid orifice that leads to a primary fluid plume having a single dominant component of streamwise vorticity, leading to stronger plume-plume interaction and mixing.
SUMMARY OF THE INVENTION
[0016] The orifice from which the primary fluid is emitted is given a streamlined, airfoil-like shape to create (in an extruding fashion) a steamlined jet having a wing-like form in the vicinity of the orifice. The term “streamlined” refers to a body dominated by frictional drag, as opposed to pressure drag. When the wing-like jet is placed at an angle of attack in the secondary fluid cross-stream, a strong tilting force develops on the jet, much like the well known lifting force on a solid wing, causing the jet to bend away from the plane defined by the initial injection direction and the cross-stream direction. By varying the angle of attack, the magnitude of the lifting force is altered, and the penetration of the jet is strongly affected. Additionally, the lift force creates circulatory-flow (i.e. single-sided vorticity) around the jet that maintains itself far downstream of the jet orifice. Both of these effects strongly affect the penetration, mixing, and interaction of multiple fluid-wings. For a given airfoil-like orifice shape, the variation of angle of attack provides a strong control authority over the jet penetration depth. Since the angle of attack is a geometric quantity, it is independent of the exit velocity of the jet, and, thus, provides a control of jet penetration that is independent of jet exit velocity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a schematic perspective illustration of one possible embodiment of the present invention, namely a wing-like orifice geometry.
[0018] FIG. 2 is a schematic perspective illustration of a wing-like orifice geometry, and its resulting airflow patterns.
[0019] FIG. 3 is a schematic perspective view of the embodiment shown in FIG. 1 with an included solid collar attached to the orifice.
[0020] FIG. 4 is a schematic perspective illustration of an alternative embodiment of the present invention, namely a main-wing orifice and an auxiliary flap orifice.
[0021] FIG. 5 is a schematic perspective illustration of another embodiment of the present invention, namely both circular and wing-like orifices.
[0022] FIGS. 6 a - 6 c are schematic perspective illustrations of yet another embodiment of the present invention, namely a bleed-port attachment with:
[0023] FIG. 6 a being a top view,
[0024] FIG. 6 b being the front view looking along the secondary fluid stream direction and
[0025] FIG. 6 c being a side view.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0026] In the first embodiment of the invention as shown in FIGS. 1 and 2 , a surface 100 separates an upper region containing a secondary fluid moving essentially parallel to said plate from a lower region having a primary fluid at higher pressure than the pressure of the secondary fluid. The surface 100 could be part of any device that mixes cross-streams of fluids, such as combustion chambers, bleed air discharge nozzles and thrust vectoring nozzles of gas turbine engines.
[0027] In a jet engine combustion chamber, the primary air is combustion-free air injected into a combustion chamber and is referred to as quench air and the secondary air is air having fully or partially burned fuel and is referred to as front-end air.
[0028] In a jet engine bleed air discharge nozzle, the primary air is compressor bleed air and the secondary air is air external to the compressor (e.g. fan-stream air). In a jet engine thrust vectoring nozzle, the primary air is compressed bleed air and the secondary fluid is jet engine exhaust flow.
[0029] The direction of the secondary fluid is indicated by arrow 110 . The plate has at least one orifice 200 allowing fluid communication between the primary and secondary fluids. The orifice 200 comprises a perforation shaped with an airfoil-like form having a leading edge 205 , an upper 206 and a lower edge 207 slowly diverging to a point of maximum separation then slowly converging to a sharp cusp at the trailing edge 208 , so as to form an airfoil profile of conventional form. The imaginary line connecting the leading and trailing edge is called the chord, shown at line 209 . The orifice is oriented with the leading edge located upstream in the secondary fluid flow from the trailing edge and with the chord aligned with a predetermined angle to the secondary flow direction, the angle being indicated by the symbol a in FIG. 1 . The predetermined angle is called the angle of attack, and the combination of angle of attack and orifice shape, including the camber (camber is the curvature of the air foil center-line) of the airfoil, determines the lift force experienced by the primary fluid particles leaving the orifice, and hence determines the plume penetration. Airfoil shapes designed for low Reynolds number flows, as known in the art, are best suited. Given an airfoil shape, the angle of attack is chosen to satisfy the needs of each specific engineering application: low angles of attack when high penetration is desired, high angles of attack (essentially between 0 and 20 degrees) when low penetration is desired.
[0030] Due to the pressure difference between the primary fluid and the secondary fluid, a jet of primary fluid 210 is emitted from the orifice 100 into the secondary fluid cross-stream. The jet of primary fluid 210 inherits the airfoil cross-section of the orifice 200 and, consequently, forms a wing-like shape in the vicinity of the orifice 200 . The wing-shaped jet experiences a lateral force shown at arrow 300 which is proportional in strength to said angle of attack. The lateral force 300 brings the jet of primary flow substantially perpendicularly away from the plane defined by the direction of the primary fluid jet at the orifice and the direction of the secondary cross-stream, thereby lowering the overall penetration depth of the jet plume into the secondary cross-stream.
[0031] In the process of developing lift, a circulatory component of fluid motion, shown at arrows 310 and referred to as “circulation” within conventional airfoil theory, is established at the base of the jet of primary fluid 210 . This circulatory motion is convected with the primary fluid particles and remains with the primary fluid particles (Kelvins' theorem), as shown by arrows 320 , even after the jet has lost its wing-like shape and has reoriented itself in the cross-stream direction. The circulatory motion of the primary fluid particles establishes a single dominant component of streamwise vorticity in the jet plume (i.e. avoiding the two counter-rotating vortices produced by conventional orifice shapes). Thus, the circulating movement of air, as shown by the arrows 310 , is dependent on the airfoil shape of the primary fluid flow 210 and is generally proportional to the angle of attack a. In turn, the force, as shown by the arrow 300 , is generally proportional to the circulatory motion 310 and will effect both the penetration depth and the rate of dispersion for the primary fluid flow 210 into the secondary fluid flow 110 . Generally, a larger attack angle α will result in less penetration but greater dispersion. It is thus necessary to choose an appropriate attack angle that will bring about an optimum balance of penetration and dispersion. As a general guideline, it is estimated that an airfoil shaped orifice having an angle of attack of α=0°, provides a 30% greater penetration than a round orifice of the same area. Further if the same airfoil shaped orifice is presented so as to have an angle of attack of α=10°, then the penetration is estimated to be about half (50%) that of a corresponding round orifice, but with much better dispersion characteristics. As further guidance, an attack angle in the range of negative 5 to positive 25 degrees is suggested for a jet engine combustion chamber, and an attack angle of 5 to 15 degrees (as needed to place the plume away from the nacelle surfaces at downstream locations) is suggested for a jet engine bleed air discharge nozzle.
[0032] In reference to FIG. 3 , a collar, or solid sleeve 220 , is added to the perimeter of orifice 200 to “lift” the orifice off the plane 100 . Essentially, the collar gives the orifice an extension into the third dimension. The collar is beneficial, for example, in those cases when the flow through the orifice is reduced to a trickle and the trickling fluid must avoid contact with the plane 100 . Such a case exists, for example, for the bleed-air port on jet engines, wherein the trickle is caused by an incomplete closure of the bleed-air valve, and the hot trickling air can damage the nacelle when contacting the nacelle surface.
[0033] In another embodiment of the invention as shown in FIG. 4 , the orifice comprises a first and second opening. The first opening, shown at 201 , forms the “main wing” jet and the second opening, shown at 202 , forms an auxiliary flap jet whose role is to increase the efficiency and the lift force experienced by the main-wing jet, much like a conventional trailing edge flap aids the performance of the main wing at lower wing translational velocities. Furthermore, the close proximity of the main-wing jet to the flap jet creates a strong interaction between the downstream plume 330 from the main opening and the downstream plume 340 from the flap opening. This interaction leads to increased mixing of primary fluid with the secondary fluid.
[0034] Another embodiment of the invention is shown in FIG. 5 which relates to a combustor application, wherein it is desired to provide a substantially increased amount and penetration of primary airflow. For example, where the combustor maybe constrained in length and there isn't sufficient surface to rely on only airfoil shaped orifices, it maybe advantageous to use a combination of orifice shapes as shown.
[0035] In the FIG. 5 embodiment, a surface 100 of a combustor liner separates an upper region (i.e. the combustion zone) containing a secondary fluid moving parallel to said plate from a lower region having a primary fluid at higher pressure than the pressure of the secondary fluid. The secondary fluid direction is indicated by arrow 110 . The plate has a pattern of orifices for communication between the primary and secondary fluid, the pattern comprising a mixture of wing-like orifices and non-wing-like orifices. Although other shapes could be used, FIG. 5 shows the non-wing-like orifices having a circular shape. A part of this pattern is shown in FIG. 5 wherein circular orifices are shown at 400 and orifices having a wing-like streamlined cross-section are shown at 410 . Examples or orifice patterns maybe the alternating rows of circles and wings, as shown in FIG. 5 , or maybe a checkerboard pattern of circles and wings (not shown), or other patterns. A jet from circular holes forms a downstream plume of kidney-shaped cross sections, as indicated by 420 that is located away from the pate 100 , leaving a volume of secondary fluid below said plume that is not active in the mixing of the primary fluid with the secondary fluid. The juxtaposition of circular orifices with wing-like orifices, each at a predetermined angle of attack, allows a positioning of the downstream plumes from the wing-like orifices 430 below the downstream plumes from the circular orifices 420 . This produces mixing between the primary fluid and the secondary fluid over a greater volume of secondary fluid above the plate. As a further benefit, the pressure-drop between primary and secondary fluids is less than the pressure drop associated with an orifice pattern consisting of large and small diameter circular holes, wherein the small-diameter holes are used to generate an overall plume distribution that approximates the distribution generated by the airfoil-shaped orifices.
[0036] A further embodiment of the invention is shown in FIGS. 6 a, 6 b and 6 c wherein, in a bleed port attachment application, the authority over plume penetration is used to construct a bleed-port attachment that positions and shapes the exhausted bleed-air plume into a desired form and trajectory. A surface 100 ( FIG. 6 ) separates an upper region (e.g. the fan duct) containing a secondary fluid (namely bypass air) moving parallel to said plate from a lower region (e.g. ducts in communication with the compressor section of the gas turbine engine) having a primary fluid (namely core engine air) at higher pressure than the pressure of the secondary fluid. The attachment comprises at least two wing-shaped orifices with collars, and preferably four orifices with collars oriented with an angle of attack with respect to the secondary fluid stream direction, indicated by arrow 110 in FIG. 6 a. The orifices and collars provide communication between the primary and secondary fluids, and the pressure difference between the primary and secondary fluids generates a jet of primary fluid from each orifice, the jet having an airfoil-like cross section and a wing-like form in the vicinity of each orifice. When the primary fluid plume must be spread over a wide space within the secondary fluid stream, at least two orifices with collars are positioned with opposite directed lift directions, such as collars 602 and 603 in FIG. 6 , such that the corresponding emitted plumes 702 and 703 spread laterally away from one another as each plume convects in the secondary cross-stream flow. The angle of attack of the orifices plus collars 602 and 603 is increased or decreased to reduce or increase plume penetration into the secondary stream, as desired.
[0037] When four orifices with collars are used, the outer two collars 601 and 604 are each oriented to give a lift directed in the same direction as that of the neighboring inner collar, and the outer two collars 601 , 604 are preferably titled away from the perpendicular direction to plane 100 to further assist the lateral displacement of associated plumes 701 and 704 . When the plumes emitted from the inner orifices 601 , 602 penetrate further into the secondary air stream than the plumes from the outer orifices 601 , 604 , and an essentially equal penetration of plumes from all four orifices is desired, the collars of the inner two orifices 602 , 603 are preferably lower in height than the height of the outer collars 601 , 604 .
[0038] When an asymmetric plume development downstream of the bleed port is desired, the lift direction of same, or all, of the orifices and collars maybe oriented toward the desired side of the bleed port (asymmetric bleed-port attachment not shown).
[0039] Guide vanes 620 extend from the bleed-port attachment into the piping feeding the bleed-port to partition the primary fluid flow into parts appropriate for each orifice. Furthermore, the guide vanes help prevent undesired unsteadiness in the fluid emitted from each orifice.
[0040] In addition to the advantages and benefits of the present invention as discussed hereinabove, the reduction in No x gas resulting from lowered operating temperatures should be mentioned. In this regard, it should be recognized that, in a jet engine combustion chamber, the secondary fluid contains combustible fuel as it approaches and passes around the plume being introduced by the primary fluid. When this plume is substantially round, as will be the case for round orifices, there will be a substantial wake created on the downstream side of the primary fluid plume. The entrained fuel tends to remain within that wake and its temperature is, accordingly, caused to rise to the point where No x gases are formed. This is to be contrasted with the rather sharp trailing edge of a primary fluid plume resulting from an airfoil shaped orifice. Here, there is very little, if any, wake created at the trailing edge and therefore the fuel is not trapped in this area, but continues to flow downstream and remain at temperatures that are not likely to cause No x formation.
[0041] While the present invention has been particularly shown and described with reference to the preferred mode as illustrated in the drawing, it will be understood by one skilled in the art that various changes in detail maybe effected therein without departing from the scope of the invention as defined by the claims.
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In an air mixing arrangement wherein a primary fluid is introduced through an opening in a wall to be mixed with a secondary fluid flowing along the wall surface, the opening is airfoil shaped with its leading edge being orientated at an attack angle with respect to the secondary fluid flow stream so as to thereby enhance the penetration and dispersion of the primary fluid stream into the secondary fluid stream. The airfoil shaped opening is selectively positioned such that its angle of attack provides the desired lift to optimize the mixing of the two streams for the particular application. In one embodiment, a collar is provided around the opening to prevent the secondary fluid from contacting the surface of the wall during certain conditions of operation. Multiple openings maybe used such as the combination of a larger airfoil shaped opening with a smaller airfoil shaped opened positioned downstream thereof, or a round shaped opening placed upstream of an airfoil shaped opening. Pairs of openings and associated collars maybe placed in symmetric relationship so as to promote mixing in particular applications, and nozzles maybe placed on the inner side of wall to enhance the flow characteristics of the primary fluid.
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BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a hole opener boring apparatus and method for using such and more particularly to an improved mounting structure for a hole opener that allows a greater number of cutters to be placed on the hole opener.
2. Description of Related Art
Hole openers are used when pipelines, cables, or culverts, for example, must be installed under surface barriers such as highways, buildings, waterways and other surface obstructions without disturbing the surface. Before a hole opener is used, a trench is opened on both sides of the barrier. A pilot bore is formed under the barrier. If the pilot bore is of insufficient diameter to install the pipeline, then the hole may be opened up using a hole opener. Next a boring head which is also referred to in the art as a reamer or hole opener, is used to enlarge the pilot bore. Generally, a guide is positioned on the advancing side of the boring head. The guide on the boring head is designed to engage the walls of the pilot bore and help steer the pipeline boring head while the pilot bore is being enlarged. Drilling fluids are also supplied to the boring operation through the drill stem in the pilot bore to produce a slurry which floats the drilled material out the end of the hole. After a hole is opened up using the hole opener, a section of the pipeline is either pushed or pulled lengthwise through the bore from one side of the barrier to the other. The pipeline may also be pulled through by the hole opener as the hole is being opened. The installed pipeline section may then be welded into place and tested.
Various types of reamers or hole openers have been disclosed in the prior art. One such opener has cone cutters which are mounted around the circumference of an axial shaft called a drill stem that is used to drive the hole opener. These cutters have been mounted by attaching plates perpendicular to the drill stem to which the cutters are then attached. The number of cutters that may be mounted to the drill stem using current methods is limited because of the tremendous forces placed on the cone cutters when in operation. The support structure attached to the drill stem must be sufficiently strong to prevent excessive breakage during a drilling operation.
Because of the limitations posed by the current support structures used to mount the cutters to the drill stem, the number of cone cutters that may be placed around the circumference of the boring head is limited. This limitation in the number of cutters varies depending on the diameter of the cutter. However, regardless of the diameter of the cutter, the structural methods used in the prior art severely limit the number of cutters allowed. Thus, the prior art tools are very rough in operation when used in hard material such as rock or hard gravel. The prior art tools also require much more power than would be required if more cutters could be added to the circumference of the tool. The prior art hole openers are analogous to a square wheel in that they are very rough in operation, and they tend to produce holes which are elongated or egg-shaped because of the rough operation. The rough operation also increases the likelihood that the cone cutters will break and be left in the hole. The removal of cone cutters from a prior art boring head after a drilling operation has proven to be very difficult and expensive because of the primitive attachment means that have been used.
Furthermore, the tools of the prior art could not be pushed backwards through the hole easily because the tools had a tendency to sink or grab along the edges of the holes due to the flat backs of the tools. The use of only four cones on prior art devices causes excessive friction between the tool and the walls of the hole making it even more difficult to push the tools back through the hole. Thus, it is virtually impossible to push prior art tools back through the hole in order to smooth the jagged edges inside the hole and mechanically push debris out of the hole. In order to produce a clean hole using prior art tools, the tool is pulled through very slowly while drilling fluids are liberally applied at the hole opener to produce a slurry that floats the debris out of the hole. Alternatively, a different tool may be attached to the drilling rig for pushing the debris out of the hole. However, this is very time consuming because of the time required in changing the tools and is more expensive because a separate tool is required.
Therefore, it would be desirable to provide a hole opener more analogous to a round wheel to reduce vibration and to reduce the size of the power supply required to operate the tool. A reduction in the size of the power supply would allow smaller boring machines to enter markets which were previously open only to larger drilling rigs. A support structure for the hole cutters is needed which will accommodate an increased number of cone cutters around the circumference of the boring head to provide a hole opener which operates smoothly. It is also desirable for the hole cutter to be capable of collecting cone cutters as they break off to avoid leaving the broken cone cutters in the hole and thereby reduce the expense of drilling operations. Furthermore, the cone cutters should be easily removable so that new or different styles or sizes of cone cutters may be installed between drilling operations. Finally, the hole cutter should be capable of being pushed back through the hole in order to provide an effective and efficient means for mechanically pushing the material out the end of the hole without requiring the insertion of a different tool.
SUMMARY OF THE INVENTION
The present invention provides a hole opener support structure which allows for a greater number of cone cutters to be attached to the hole opener. Increasing the number of cone cutters decreases the roughness of operation of the hole opener and produces a hole which is round rather than oblong or egg-shaped. Consequently, much less power is required to operate a hole opener of the same diameter than is required by the prior art tools. The support structure provided by the present invention uses a barrel which is attached to the drill stem to effectively increase the diameter of the drill stem so that additional cutters may be attached to the hole opener. Using the barrel structure, the structural integrity of the tool is not compromised, and a strong support structure for the cutters is provided. The tapered shape of the hole opener allows the hole opener to be easily pushed back through the hole to displace debris left behind the hole opener as the hole is being cut. Because debris may be mechanically displaced from the hole using the method of the present invention, much less drilling fluid is required to open a hole.
In one embodiment of the present invention, the barrel has openings in the front and back to allow drilling fluid and material to pass through the hole opener. The openings are such that broken cone cutters are deposited through the front openings and trapped in the barrel, thereby preventing the broken cone cutters from being left in the hole. Furthermore, the cone cutters may be easily removed from the barrel between drilling operations. This feature is provided by embedding a bolt in a groove within the cone cutter segment. The bolt is used to secure the segment to a pocket attached to the barrel. Because the bolt itself is replaceable, the life of the cone cutter segments are prolonged. This results in a very versatile tool in that the same hole opener may be used for boring various types of materials, and less time is required to change worn-out cone cutters.
BRIEF DESCRIPTION OF THE DRAWINGS
The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will be best understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings wherein:
FIG. 1 is a front perspective view of an embodiment of a hole opener in accordance with the present invention.
FIG. 2 is a side view of the hole opener of FIG. 1 with segments removed.
FIG. 3 is a side view of the hole opener of FIG. 1 as illustrated with segments installed into tapered pockets.
FIG. 4 is a rear perspective view of the hole opener of FIG. 1 .
FIG. 5 is a front perspective view illustrating another embodiment of a hole opener in accordance with the present invention.
FIG. 6 is a top view of a segment used in one embodiment of the present invention.
FIG. 7 is a side view of a segment used in one embodiment of the present invention.
FIG. 8 is a bottom view of a segment used in one embodiment of the present invention.
DETAILED DESCRIPTION
Referring now to FIG. 1, a front perspective view of an embodiment of a hole opener in accordance with the present invention is illustrated. A drill stem 105 extends from the front of the cutter to act as a pilot and a drive shaft for the hole opener. The drill stem 105 is threaded to allow extensions of the drill stem 105 to be attached. The drill stem 105 passes through a pilot hole that is bored prior to the insertion of the hole opener. The drill stem 105 is hollow for pumping drilling fluid through the drill stem and out fluid ports to liquify the material into a mud so that it more easily passes through or around the hole opener during the drilling operation. Water tubes 110 in fluid communication with the drill stem 105 may be attached to the drill stem to act as a fluid communicator to spray water out over the loose material. The water tubes 110 have several small holes drilled in them to allow the water to be dispersed at different intervals along the hole opener. Attached to the drill stem 105 is a front plate 115 and a rear plate 120 that extend substantially perpendicular from the drill stem 105 . Bridging the outer edges of the front plate 115 and the rear plate 120 is a cylindrical ring 125 . The ring need not be cylindrical but could, for example, be in the shape of a polygon with a number of sides depending on the number of cutters to be installed on the hole opener. The cylindrical ring 125 can be a steel pipe of the appropriate diameter that is welded to the outside edges of the front and rear plates 115 , 120 . The diameter of the plates 115 , 120 and cylindrical ring 125 is dependent upon the desired diameter of the cutting tool. The combination of the front plate 115 , the rear plate 120 , and the cylindrical ring 125 is referred to herein as a barrel because a hollow cylindrical structure is formed around the drill stem 105 . In alternate embodiments, the barrel need not be formed of separate pieces but could be cast as one individual piece having holes through which the drill stem may be inserted and secured in place.
For tools of sufficient diameter, material ports 130 may be located in both the front plate 115 and the rear plate 120 . The material ports 130 allow material such as dirt, mud, and rocks to pass through the hole opener while it is in operation. Material ports such as these can be placed in the front plate 115 and rear plate 120 without compromising the structural integrity of the support structure for the cone cutters 135 . For a hole opener of sufficient diameter, the material ports in the front plate 115 can be made large enough such that if a cone cutter 135 breaks off during operation it will pass through one of the material ports 130 in the front plate 115 and be trapped inside the barrel. The material ports in the back plate are made smaller than the cone cutter 135 so that the cone cutter 135 cannot pass through the material ports in the rear plate 120 . Thus, whenever the hole opener is pulled from the hole the cone cutter 135 that was broken off is also removed. Normally, if a cone cutter is left in the hole, the hole must be redrilled at a different location. Thus, considerable expense is saved by producing a hole which is clean and free of debris or other material that would damage a pipe as it is being pulled into the hole. Although the embodiment of FIG. 1 shows four material ports of a rectangular shape, any number of ports of various shapes may be used without departing from the scope and spirit of the invention. Furthermore, although an equal number of material ports are shown in the front plate 115 and the rear plate 120 , a different number of ports could be placed in the rear plate 120 . As an example, if the material ports in the rear plate are smaller than those in the front plate 115 it may be desirable to provide a greater number of ports in the rear plate 120 to allow the material to flow through more easily. Thus, it is also obvious that the material ports in the front plate need not be in alignment with the material ports in the rear plate.
Each cone cutter 135 is attached to a support arm which is described in greater detail below. The support arm of each cone cutter 135 is attached to the cylindrical ring 125 . The cone cutters 135 can have different patterns for the rows of teeth to avoid a strip in the hole being drilled which is not being touched by the teeth. Two different cutter patterns 135 a , 135 b are shown in FIG. 1 . The invention is not limited to a hole opener with only two cutter patterns. The tool could have four or more different patterns depending on the number of cone cutters to reduce vibration. For example, the use of a four-cone pattern further reduces vibration by requiring each cone to cut less material than would a three-cone pattern. The present invention, by allowing more cutters to be placed around the circumference of the hole opener, also allows a greater number of cone patterns to be implemented.
The combination of the cone cutter with the support structure is referred to herein as a segment 140 . Tapered pockets 145 are attached around the circumference of the barrel to provide a receptacle for the segments 140 . Thus, the segments 140 may be removed and replaced as they wear out or as different types of material are encountered requiring different types of cone cutters. It is well known in the art that the cone cutters 135 will vary depending upon the type of material that is being bored. Cone cutters of different type and orientation than that shown in FIG. 1 may be used without departing from the scope and spirit of the invention. Furthermore, a combination of different types of cutters may be used at the same time to provide a more efficient hole opener. In addition, cone cutters of a different diameter than those shown in FIG. 1 could be used to change the overall diameter of the hole opener, thereby making small changes in the diameter of the resulting hole as desired.
Typically, the hole opener is pulled through the pilot hole using the drill stem 105 . A power source is attached to the front side of drill stem 105 to provide a rotational force as well as a pulling force for operating the hole opener. If the hole opener is operated in a counter-clockwise direction 150 , each of the cone cutters rotate in a direction 155 opposite the rotation of the tool as they contact the material being drilled.
Referring now to FIG. 2, a side view of the hole opener of FIG. 1 is illustrated with the segments 140 removed. Throughout the detailed description, like numerals are used to denote like parts unless otherwise noted. The tapered pockets 145 are preferably made of mild steel and welded to the barrel 125 . Mild steel allows a certain amount of stretch which results in a tighter fit for the segments 140 . The water tubes 110 are placed adjacent to the front plate 115 behind the cutting plane of the cone cutters 135 .
Referring now to FIG. 3, a side view of the hole opener of FIG. 1 is illustrated with the segments 140 installed into the tapered pockets 145 . The removable segments 140 may be secured using a locking hexnut 305 or may be double nutted to prevent inadvertent loosening of the segment during operation. Tightening the hexnut produces a friction lock between the segment 140 and the tapered pocket 145 . A flange 310 protruding from segments 140 is used to provide a stop to indicate that segment 140 has been drawn completely into the tapered pocket 145 .
Referring now to FIG. 4, a rear perspective view of the hole opener of FIG. 1 is illustrated. The material ports 405 in the rear plate 120 are smaller than the material ports 130 that are in the front plate. This prevents a broken cone cutter 135 from passing through the barrel 125 once it is trapped inside. The rear end of the drill stem 105 may be threaded to allow the attachment of additional hole openers of larger diameter depending on the diameter of the hole that must be drilled and the power source available to drive the tool. Thus, if sufficient power is available, a large diameter hole may be opened using two or more hole openers of increasing diameter attached in series. If an additional hole opener is not being used, then the rear end of the drill stem may be capped to prevent water from flowing out of the drill stem and to protect the threads on the drill stem.
Referring now to FIG. 5, another embodiment of a hole opener in accordance with the present invention is illustrated. This embodiment has fewer cone cutters 135 than are illustrated in the embodiment of FIG. 1 to allow the diameter of the hole opener to be decreased while keeping the same size cone cutters. In this embodiment there are no holes in the front plate 510 or the rear plate (not shown). This is because there is not enough room between the drill stem 520 and the cone cutters 135 to allow for material ports. However, for a cutter of this size, there is sufficient room between the cone cutters 135 for material to pass. Because the diameter of the hole is much smaller, there is less material that is required to be passed by the cutter, and therefore, the holes in the plates are unnecessary in this embodiment. The tapered design of the hole opener from front to back, as can be seen in FIG. 2 or FIG. 3, also allows for the passage of material over the top of the segments 140 .
The tapered design of the embodiment of the invention shown allows the hole opener to be easily pushed back through the hole that has been cut. The hole opener may also be rotated as it is being pushed back through the hole. This “double cutting” of the hole provides a much cleaner hole than was possible with prior art tools by pushing the loose material out of the hole. When drilling a hole of a length that requires the use of multiple segments of drill stem, the hole opener may be pushed back to the point of entry before removing each segment of the drill stem. This process makes it easier to mechanically push debris out of the hole because the debris is removed in smaller portions. Then, when the hole is drilled all the way through, the tool can be pushed back to the point of entry one final time and attached to the pipeline or cable and pulled back through the hole for removal at the point of exit. Using this method, it is not necessary to flood the hole with enough drilling fluid to wash the debris out of the hole. Thus, much less drilling fluid is used and a cleaner hole results.
The barrel 505 may be made from a pipe of smaller diameter than that in FIG. 1, but it accomplishes the same purpose of providing a support structure for the cone cutters 135 which allows more cone cutters 135 to be placed around the diameter of the hole cutter than was allowed using prior art methods. Therefore the tool is much smoother operating and requires less power to operate. This embodiment also illustrates the use of a water reservoir 525 rather than the water tubes 110 shown in FIG. 1 . The reservoir can be made using a reducer by welding it to the front plate 510 and the drill stem 520 . Holes are cut in the reservoir 525 to allow water to be dispersed and mixed with the loose material. Water is pumped into the reservoir 525 through holes drilled in the drill stem 520 located inside the reservoir 525 .
Referring now to FIG. 6, a top view of the segment 140 shown in FIG. 1 and FIG. 5 is illustrated. The flange 310 used to provide a stop for the segment 140 is illustrated in greater detail. The taper 605 of the segment is also illustrated. This tapered design allows a wedge fit between the segments 140 and the pocket 145 thereby securing the segment 140 tightly to the barrel 125 to avoid movement caused by excessive forces during operation.
Referring now to FIG. 7, a side view of the segment 140 is illustrated. The tapered support arm 705 of the segment 140 is tapered along several planes to prevent the segment from twisting or turning inside the pocket during operation. The bottom 710 of the tapered arm may be curved slightly to allow a snug fit with the barrel. Thus the bottom is relatively flat compared to the remainder of the tapered arm 705 . Alternatively, the support arm could be cone-shaped with a keyway cut in the support arm for inserting a key which would mate with a keyway inside a cone-shaped pocket. Thus the tapered arm could be cone shaped without the planes used in the embodiment shown. Other emodiments of this pocket structure may be used without departing from the scope and spirit of the invention.
Referring now to FIG. 8, a bottom view of the segment 140 is illustrated. A slot 805 in the segment is provided for a hexhead bolt to be placed for meshing the segment 140 in the tapered pocket. The bolt slides down inside the slot 805 and is held in place by the barrel 125 as the segment is slid into the tapered pocket. The slot is such that the bolt is not allowed to rotate within the segment 140 when the segment 140 is placed inside the tapered pocket 145 . Because the bolt is removable from the slot whenever the segment is removed from the tapered pocket, the bolt may be replaced if it is damaged during removal or operation of the hole cutting tool. In fact, the bolt itself may be used to drive the segment out of the tapered pocket by removing the nut from the end of the bolt and hammering directly on the bolt. Obviously, when the bolt is hammered in this manner, the threads may be damaged, but because the bolt can be removed easily, it can be replaced with a new bolt when the segment is reinserted into the tapered pocket. If the segments were tapped with threads instead of using a bolt insert as described above, the whole segment would have to be replaced if the threads inside the segment were damaged or stripped. Thus, the present invention saves significant expense by increasing the life of the segments using the replaceable bolts.
Thus, the present invention provides a means for mounting segments on a hole opener which allows the segment to be spaced closer together while providing better structural support than is allowed in the prior art. The means for mounting the segments in the prior art limits the number of segments that may be placed in a plane perpendicular to the drill stem to four segments. Smaller boring heads may receive from one to two extra segments using the method of the present invention. The addition of extra segments increases the cutting surface of the tool and results in a smoother operation requiring less torque from the power source drill stem. The tool of the present invention also allows a finished hole which is more round than is allowed by the tools of the prior art.
While the invention has been particularly shown and described above with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention. For example, various types of cutters may be used. The tapered pockets for the segments could be of a different shape. Numerous types of attachments to the barrel itself may be used, and different styles of drilling fluid transfer could be used, all without departing from the scope and spirit of the invention.
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A hole opener and method for using same which allows for a greater number of cone utters to be attached to the hole opener. The support structure provided by the present invention uses a barrel which is attached to the drill stem to effectively increase the diameter of the drill stem so that additional cutters may be attached to the hole opener. Using the barrel structure, the structural integrity of the tool is not compromised, and a strong support structure for the cutters is provided. The cone cutters may be removable from the barrel. The removable structure is provided by placing a bolt inside the segments which is used to mate the segment with a pocket attached to the barrel. This results in a very versatile tool in that the same boring head may be used for boring various types of materials. The barrel structure of the present invention also provides a means for trapping cones inside the barrel to prevent the cone cutters from being left inside the hole. The tapered shape of the hole opener allows it to be forced back to the point of entry after drilling in order to displace debris.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an apparatus for manufacturing a semiconductor device, and more particularly, to an apparatus for manufacturing a semiconductor device with improved uniformity of plasma density.
[0003] 2. Description of the Related Art
[0004] Apparatuses for manufacturing semiconductor devices can be classified as an apparatus for forming a thin film on a semiconductor substrate, an apparatus for performing a photolithography process to form a mask pattern on the thin film to form fine patterns, an apparatus for etching the thin film using the mask pattern as an etching mask to form fine patterns, and an apparatus for implanting impurity ions into the semiconductor substrate. As the line width of patterns is reduced due to increased integration density of semiconductor devices, the quality and capabilities of etching apparatuses and deposition apparatuses used for forming fine patterns become more important. Etching apparatuses are typically classified as either dry etching apparatuses, such as plasma etching apparatuses, and wet etching apparatuses. As the integration density of semiconductor devices increases, dry etching apparatuses, which enable anisotropic etching to be performed, are typically used, and apparatuses adopting a chemical vapor deposition method using plasma, e.g., plasma-enhanced chemical vapor deposition (PE-CVD), are used as deposition apparatuses.
[0005] [0005]FIGS. 1A and 1B show two-dimensional views of apparatuses for manufacturing a semiconductor device according to the prior art. FIG. 1A shows an induced coupled plasma etching apparatus 10 having a dielectric plane structure, and FIG. 1B shows an induced coupled plasma etching apparatus 40 having a dielectric dome structure. For illustrative convenience, it is considered that chambers 12 and 42 are cylindrical, lower electrodes 26 and 56 are circular plates, an insulating plate 20 shown in FIG. 1A is circular, and an insulating plate 50 shown in FIG. 1B is dome-shaped. A plurality of induction coils 14 shown in FIG. 1A for generating a plasma source span a distance that is substantially equal to the diameter L1 of the insulating plate 20 . Similarly, a plurality of induction coils 44 shown in FIG. 1B span a distance that is substantially equal to the length of curved surface of the insulating plate 50 . The insulating plate 20 and the lower electrode 26 shown in FIG. 1A have almost the same diameters L1 and L2, and the projected diameter L4 of the curved surface of the insulting plate 50 shown in FIG. 1B is designed to be substantially equal to the diameter L5 of the lower electrode 56 . The diameters of wafers 30 and 60 supported by static chucks 28 and 58 that are mounted on the lower electrodes 26 and 56 are designed to be smaller than the diameters of the lower electrodes 26 and 56 .
[0006] Confinement layers 22 and 52 , which confine plasma regions 24 , 54 a , and 54 b , are designed to contact the edges of the insulating plates 20 and 50 and extend in a direction that is perpendicular to the lower electrodes 26 and 56 .
[0007] Referring to FIGS. 1A and 1B, insulating layers or conductive layers are deposited on the wafers 30 and 60 and then etched to obtain desired patterns.
[0008] A low-frequency power supplied from first power supplies 16 and 46 is applied to a plurality of induction coils 14 and 44 to generate a magnetic flux. Inductance of coils 14 and 44 creates an electric field and a magnetic field in a plasma region 24 , 54 a , and 54 b via the insulating plates 20 and 50 included in the chambers 12 and 42 . Here, a high-frequency external power is supplied to the lower electrodes 26 and 56 via second power supplies 18 and 48 . Electrons move due to the magnetic field and the electric field in the plasma regions 24 , 54 a , and 54 b and are accelerated to bombard a reactive gas to generate reactive ions of plasma. The reactive ions are diffused/absorbed into objects to be etched on the wafers 30 and 60 .
[0009] Since plasma (or reactive ions) is incident to the center of the wafers 30 and 60 and diffused into the sides of the wafers 30 and 60 , plasma density at the center of the wafers 30 and 60 is higher than plasma density at the edge of the wafers 30 and 60 . Thus, since a large amount of plasma is incident to the center of wafers 30 and 60 , patterns positioned at the center of the wafers 30 and 60 are over-etched. Since a small amount of reactive ions is diffused/absorbed at the edge of the wafers 30 and 60 , patterns positioned at the edge of the wafers 30 and 60 are under-etched. Since the under-etched or over-etched patterns can greatly affect a subsequent process and/or the characteristics of the semiconductor device, it is important to maintain uniformity of etching throughout a wafer.
[0010] The above-described non-uniformity of plasma density occurs in deposition apparatuses as well as etching apparatuses. The thickness of a pattern formed at the edge of a wafer is thinner than the thickness of a pattern formed at the center of the wafer, and thus uniformity of the patterns is not ensured.
[0011] In order to meet semiconductor users' demand for high added value as well as low price, the price of semiconductor devices is typically lowered by manufacturing a large number of chips in a single process, i.e., using large diameter of wafers. Wafers having a diameter of 200 mm are typically used for producing most advanced semiconductor devices, such as memories and logics. However, it is expected that semiconductor devices will soon be mass-produced using wafers having diameters of 300 mm.
[0012] The differences in plasma density at different locations on a wafer becomes more pronounced for such larger-diameter wafers. A variety of techniques for correcting non-uniformity of plasma density have been proposed for wafers having a diameter of 200 mm, but these fail to adequately ensure etching uniformity and deposition uniformity when processing wafers having a diameter of 300 mm. Further, since plasma density is low at the edge of wafers, etch rate or deposition rate necessary for forming patterns at the edge of the wafers according to a design is not typically attained.
[0013] Accordingly, the semiconductor industry requires a technique by which a high plasma density region is formed on a wafer having a large diameter (i.e. over 200 mm and 300 mm) in order to obtain uniform etching and/or deposition throughout the wafer.
SUMMARY OF THE INVENTION
[0014] To solve the above-described problems, it is a feature of the present invention to provide an apparatus for manufacturing a semiconductor device with improved uniformity of plasma density throughout.
[0015] It is another feature of the present invention to provide an apparatus for manufacturing a semiconductor device having improved effective plasma density.
[0016] Accordingly, there is provided an apparatus for manufacturing a semiconductor device using plasma. The apparatus includes a chamber for performing a manufacturing process on the semiconductor device under a plasma atmosphere and a device installed in the chamber for concentrating the plasma. The device reduces the size of a plasma region near an object to be processed as compared to the size of a plasma region near a part of the chamber where the plasma is generated. The device for concentrating the plasma includes: a lower electrode having a first length on which the object to be processed is positioned; an insulating plate having a second length that is longer than the first length and that is separated from and facing the lower electrode; and a confinement layer contacting the edge of the insulating plate, forming an acute angle to a virtual plane connecting opposing ends of the insulating plate, and extending toward the edge of the lower electrode. The diameter of the circular plate is the first length if the lower electrode is a circular plate. Here, the acute angle is preferably 45-89 degrees.
[0017] In more detail, the insulating plate includes a first part having a first radius of curvature and a second part having a second radius of curvature which is smaller than the first radius of curvature, and the edge of the second part of the insulating plate is connected to the confinement layer. The insulating plate may have a dome shape having a predetermined radius of curvature. The insulating plate may be a circular plate. Here, the second length is the diameter of the circular plate.
[0018] The device for concentrating plasma preferably includes: a lower electrode having a first length; an insulating plate having a dome shape, which is oriented to face the lower electrode and includes a first part having a first radius of curvature and a second part having a second radius of curvature which is smaller than the first radius of curvature; and a confinement layer connected to the second part of the insulating plate and extending toward the lower electrode. Here, a second length, which is the projected length of the insulating plate, is larger than the first length. The confinement layer is substantially perpendicular to the projected surface of the insulting plate.
[0019] The apparatus for manufacturing a semiconductor device further preferably includes a chuck for supporting a wafer having a third length and preferably being located above the lower electrode. The wafer is preferably a circular plate, and thus the third length becomes the diameter of the wafer. The diameter or projected length of the insulating plate is preferably over about 140% of such a third length. The length of the bottom of the confinement layer is preferably over about 120% of such a third length. The distance from the edge of the confinement layer to the edge of the wafer is preferably about 10-15% of the third length.
[0020] For an exemplary wafer having a diameter of 300 mm, a corresponding second length of the insulating plate would be approximately 420 mm and the diameter of the bottom edge of the confinement layer would be approximately 360 mm.
[0021] Although the preceding confinement layer is described as a perpendicular element and is distinguished from the sidewall of the chamber, the confinement layer may constitute the sidewall of the chamber and may be slanted.
[0022] The apparatus for manufacturing a semiconductor device further includes a device for generating plasma in a plasma region of the chamber. The device for generating plasma may include a first power supply connected to a plurality of induction coils and a second power supply connected to the lower electrode where an object to be processed is positioned. The device for generating plasma may be an integral part of the chamber, or it can be located external to the chamber with the plasma being introduced into the chamber by other means.
[0023] Another embodiment of the present invention for increasing plasma density at the edges of a semiconductor device during a plasma-etch manufacturing process, comprises: a first chamber for generating a plasma and a second chamber, wherein the semiconductor device is positioned; and characterized in that the second chamber has a smaller cross-sectional area than the first chamber. The embodiment preferably includes a plurality of induction coils for generating the plasma in the first chamber and an electrode for attracting the plasma into the second chamber.
[0024] Another embodiment of the present invention for improving the uniformity of a plasma density at a semiconductor device in a plasma-etch manufacturing process, comprises: a first chamber, wherein a plasma is generated; and a second chamber, wherein the semiconductor device is positioned; and characterized in that the second chamber has a smaller cross-sectional area than the first chamber. The embodiment preferably includes a plurality of induction coils for generating the plasma in the first chamber and an electrode for attracting the plasma into the second chamber.
[0025] These and other features of the present invention will be readily apparent to those of ordinary skill in the art upon review of the detailed description that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The above features and advantages of the present invention will become more apparent by describing in detail preferred embodiments thereof with reference to the attached drawings in which:
[0027] [0027]FIGS. 1A and 1B illustrate schematic diagrams of the structure of an apparatus for manufacturing a semiconductor device according to the prior art;
[0028] [0028]FIG. 2 illustrates a schematic diagram of an apparatus for manufacturing a semiconductor device according to a first embodiment of the present invention;
[0029] [0029]FIG. 3 illustrates a schematic diagram of an apparatus for manufacturing a semiconductor device according to a second embodiment of the present invention;
[0030] [0030]FIG. 4 illustrates a schematic diagram of an apparatus for manufacturing a semiconductor device according to a third embodiment of the present invention; and
[0031] [0031]FIG. 5 illustrates a schematic diagram of an apparatus for manufacturing a semiconductor device according to a fourth embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0032] Korean Patent Application No. 01-24045, filed on May 3, 2001, and entitled: “Apparatus for Manufacturing Semiconductor Device,” is incorporated by reference herein in its entirety.
[0033] Hereinafter, the present invention will be described in detail with reference to the attached drawings.
[0034] The apparatuses of the present invention increase effective plasma density and concentrate plasma density at the edge of the wafer, which heretofore would have a relatively lower plasma density than at the center of the wafer. A principal feature of the preferred embodiments of the present invention is that a plasma region in a vacuum chamber must be larger at a location where the plasma is introduced than at a location where an object to be treated on a lower electrode is positioned.
[0035] For illustrative convenience, although the figures illustrate two dimensional representations, it is considered that in all of the embodiments that the chambers are preferably cylindrical in shape, and that the lower electrodes and insulating plates are circular planar elements within those cylindrical shapes. Reference to the lengths of different elements are also meant to refer to the diameters when such elements are circular. For non-circular chambers, references relating to lengths may also be used to describe depth into the plane of the drawing. It should also be understood that references to upper and lower are for illustration purposes only, and not meant to be limiting, since plasma migration is a function of an electrical field rather than gravity, thereby having applicability to a chamber having any orientation.
[0036] [0036]FIG. 2 shows an apparatus for manufacturing a semiconductor device according to a first preferred embodiment of the present invention. Referring to FIG. 2, an apparatus 100 for manufacturing a semiconductor device preferably includes a vacuum chamber 112 , a plurality of induction coils 114 mounted on the vacuum chamber 112 , a first power supply 116 for supplying the plurality of induction coils 114 with low frequency power, and a second power supply 118 for supplying a lower electrode 126 with high-frequency power. A chuck 128 for supporting a wafer 130 is preferably positioned on the lower electrode 126 . Plasma generated from the plurality of induction coils 114 may be introduced into the vacuum chamber 112 via a plurality of holes (not shown) that are formed in an insulating plate 120 . The diameter of the insulating plate 120 is M1, which corresponds to the distance spanned by the plurality of induction coils 114 . The wafer 130 may have a predetermined diameter M3 and be positioned a predetermined distance M4 from a confinement layer 122 to allow etching by-products to be exhausted via the spaced portion.
[0037] There are significant differences between the apparatus shown in FIG. 1A and the apparatus shown in FIG. 2. First, the diameter M2 of the lower electrode 126 shown in FIG. 2 is preferably smaller than the diameter M1 of the insulating plate 120 of FIG. 2. Second, in the vacuum chamber 112 of FIG. 2, the confinement layer 122 , which contacts the edge of the insulating plate 120 and extends toward the lower electrode 126 , is preferably not perpendicular to the insulating plate 120 , rather it preferably forms an acute angle θ 1 to the insulating plate 120 . For example, it is preferable that the acute angle θ 1 of the confinement layer 122 be in the range of 45-89 degrees. Accordingly, since the insulating plate 120 and the lower electrode 126 shown in FIG. 2 are circular plates, the confinement layer 122 has a cylindrical shape, the diameter of which is reduced at an end closer to the lower electrode 126 . A resulting plasma region 124 has the same shape as the confinement layer 122 , i.e., cylindrical. Thus, when compared to an apparatus adopting a confinement layer 22 that is perpendicular to the lower electrode 26 shown in FIG. 1, the apparatus of the present invention produces slight plasma density increases near the edge of the wafer 130 , but not near the center of the wafer 130 . This produces an overall uniform plasma density on the wafer 130 .
[0038] For a wafer 30 shown in FIG. 1A having a diameter identical to the diameter M3 of the wafer 130 shown in FIG. 2, the diameter M1 of the insulating plate 120 shown in FIG. 2 would preferably be larger than the diameter L1 of an insulating plate 20 in FIG. 2. Thus, the distance spanned by the plurality of induction coils 114 shown in FIG. 2 would be greater than distance spanned by the plurality of induction coils 14 shown in FIG. 1A.
[0039] The distance spanned by the plurality of induction coils 114 and the diameter M1 of the insulating plate 120 is preferably over 140% of the diameter M3 of the wafer 130 to be etched and preferably over 120% of the diameter M2 of the lower electrode 126 . The distance M4 between the edge of the lower electrode 126 and the edge of the wafer 130 is preferably designed to be 10-15% of the diameter M3 of the wafer 130 . For example, for a wafer 130 having a diameter M3 of 300 mm, the diameter M1 of the insulating plate 120 would be approximately 420 mm and the diameter M2 of the lower electrode 126 would be approximately 360 mm. The exemplary distance M4 between the edge of the lower electrode 126 and the edge of the wafer 130 would be 30-45 mm.
[0040] According to the above-described embodiment, even though the first and second power supplies, 116 and 118 , respectively, do not increase the power and pressure in the vacuum chamber 112 , the cross-sectional area of the plasma region 124 , which is defined by the cylindrical confinement layer 122 , is smaller near the wafer 130 than near the insulating plate 120 . This effectively increases useable plasma density of a given amount of plasma generated, and substantially increases the plasma density near the edge of the wafer. Thus, the uniformity of the distribution of plasma throughout the wafer is improved, thereby producing a uniform etch rate of patterns.
[0041] The distance spanned by the plurality of induction coils 114 that generate plasma increases with an increase in the diameter M1 of the insulating plate 120 . Since the magnetic flux generated by the plurality of induction coils 114 shown in FIG. 2 is greater than the magnetic flux generated by the plurality of induction coils 14 shown in FIG. 1A, high density plasma can be obtained using the embodiment shown in FIG. 2 over that shown in FIG. 1.
[0042] Second, third, and fourth embodiments of a plasma etching apparatus of the present invention which are modifications of the plasma etching apparatus shown in FIG. 1B are shown in FIGS. 3, 4, and 5 , respectively. Referring to FIG. 3, a chamber 212 preferably has a top that is dome-shaped. An insulating plate 220 may be configured as an upper portion of the chamber 212 that has a dome shape with a predetermined radius of curvature. The radius of curvature of the insulating plate 220 is preferably equal to or greater than the radius of curvature of an insulating plate 50 shown in FIG. 1B. According to the present invention, the projected diameter D1 of the insulating plate 220 is preferably greater than the diameter D2 of a lower electrode 226 .
[0043] For a wafer 230 having a diameter identical to wafer 60 shown in FIG. 1B, the projected diameter D1 of the insulating plate 220 would be made to be greater than the projected diameter L4 of an insulating plate 50 shown in FIG. 1B. Thus, the distance spanned by a plurality of induction coils 214 located on the outer surface of the dome-shaped chamber 212 is greater than the distance spanned by a plurality of induction coils 44 shown in FIG. 1B. The plurality of induction coils 214 generate more magnetic flux, and thus more plasma, than the plurality of induction coils 44 of FIG. 1B even when the amount of power supplied by a first power supply 216 is equal to the amount of power supplied by a first power supply 46 shown in FIG. 1B.
[0044] As described above, the projected diameter of D1 of the insulating plate 220 is greater than the diameter D2 of the lower electrode 226 . Like FIG. 2, a confinement layer 222 contacts the edge of the dome-shaped insulating plate 220 and extends toward the wafer 230 , forming an acute angle θ 2 to the projected surface of the insulating plate 220 . Thus, plasma density in a plasma region 224 increases in a direction toward the wafer 230 , and in particular, plasma density in a plasma region 224 increases significantly near the edge of the wafer 230 . As a result, high-density plasma is obtained and the uniformity of etching throughout the wafer 230 is improved.
[0045] Reference numerals 218 and 228 indicate a power supply having a high frequency and a chuck for supporting the wafer 230 , respectively. Reference number 218 and 228 correspond to reference 118 and 128 shown in FIG. 2. D4 represents the distance from the wafer 230 to the confinement layer 222 or the edge of the lower electrode 226 and corresponds to M4 shown in FIG. 2.
[0046] For example, an acute angle θ 2 may be within the range of about 45-89 degrees. The distance spanned by the plurality of induction coils 214 and the projected diameter D1 the insulating plate 220 is preferably over about 140% of the diameter D3 of the wafer 230 and preferably over about 120% of the diameter D2 of the lower electrode 226 . The exemplary distance D4 from the edge of the lower electrode 226 to the edge of the wafer 230 would be about 10-15% of the diameter M3 of the wafer 130 . For example, for a wafer 230 having a diameter D3 of 300 mm, the diameter D1 of the insulating plate 220 would be approximately 420 mm and the length D2 of the lower electrode 226 would be approximately 360 mm, and D4 would be approximately 30-45 mm.
[0047] Reference numerals 312 , 314 , 316 , 318 , 326 , 328 , and 330 in FIG. 4 denote the same members as reference numbers 212 , 214 , 216 , 218 , 226 , 228 , and 230 , respectively, in FIG. 3. In the embodiment shown in FIG. 4, plasma is concentrated by adjusting the radius of curvature of a dome-shaped insulating plate 320 rather than not by a slanted confinement layer as shown in FIGS. 2 and 3. The dome-shaped insulating plate 320 is divided into two parts, wherein a first part 320 a preferably has a relatively large radius of curvature with a second part 320 b having a relatively smaller radius of curvature. Thus, the projected diameter N1 of the first part 320 a is greater than the projected diameter N2 of the second part 320 b . The projected diameter N2 of the second part 320 b denotes the projected diameter of the dome-shaped insulating plate 320 . The projected diameter N2 of the second part 320 b may be designed to be substantially equal to the diameter N3 of a lower electrode 326 . Here, the radius of curvature or the projected diameter N2 of the second part 320 b may be determined by the diameter N4 of a wafer 330 , the distance N5 from the wafer 330 to a confinement layer 322 , and the height of the confinement layer 322 .
[0048] The radius of curvature of the first part 320 a may be designed to be equal to the radius of curvature of the insulating plate 220 shown in FIG. 3 (i.e., the projected diameter N1 of the first part 320 a is equal to D1 in FIG. 3.) Since the radius of curvature of the second part 320 b is less than the radius of curvature of the first part 320 a , the projected diameter N2 of the second part 320 b is reduced. Thus, plasma density of a second plasma region 324 b defined by the second part 320 b increases more than the plasma density of a first plasma region 324 a defined by the first part 320 a . In particular, plasma density increases at the edge of the second plasma region 324 b more than at the center of the second plasma region 324 b.
[0049] The confinement layer 322 , which extends from the edge of the second part 320 b to the wafer 330 , may be perpendicular to the projected surface of the second part 320 b . The projected diameter N2 of the second part 320 b denotes the projected diameter of the insulating plate 320 . Thus, plasma density in the plasma region 324 b is maintained in a plasma region 324 c.
[0050] Similar to the embodiments shown in FIGS. 2 and 3, a distance spanned by a plurality of induction coils 314 increases with an increase in the length of the curved surface of the insulating plate 320 , thereby resulting in an increased amount of plasma generated by the plurality of induction coils 314 without varying power and/or pressure.
[0051] For example, if the projected diameter N1 of the first part 320 a is designed to be over about 140% of the diameter N4 of the wafer 330 , the projected diameter N2 of the second part 320 b or the diameter N3 of the lower electrode 326 may be designed to be over about 120% of the diameter N4 of the wafer 330 . The distance N5 from the edge of the wafer 330 to the edge of the lower electrode 326 may be designed to be 10-15% of the diameter N4 of the wafer 330 . For example, for a wafer 330 having a diameter of 300 mm, the projected diameter N1 of the first part 320 a would be over about 420 mm and the projected diameter N2 of the second part 320 b or the diameter N3 of the lower electrode 326 would be over about 360 mm. The exemplary distance N5 from the edge of the wafer 330 to the edge of the lower electrode 326 would be designed to be 30-45 mm.
[0052] Reference numerals 412 , 414 , 416 , 418 , 426 , 428 , and 430 in FIG. 5 denote the same members as reference numerals 212 , 214 , 216 , 218 , 226 , 228 , and 230 , respectively, in FIG. 3. In an etching apparatus shown in FIG. 5, the radius of curvature of an insulating plate 420 is adjusted to concentrate plasma to a predetermined area, and a confinement layer 422 is preferably slanted at a predetermined angle θ 3 so that plasma is further concentrated to the predetermined area.
[0053] A dome-shaped insulating plate 420 includes two parts 420 a and 420 b , similar to the insulating plate 320 having the two parts 320 a and 320 b shown in FIG. 4. In other words, the dome-shaped insulating plate 420 preferably includes a first part 420 a having a relatively larger radius of curvature P1 and a second part 420 b having a relatively smaller radius of curvature P2. The projected diameter of the first part 420 a is greater than the projected diameter P2 of the second part 420 b or the diameter P3 of the lower electrode 426 . The projected diameter P2 of the second part 420 b denotes the projected diameter of the dome-shaped insulating plate 420 .
[0054] The confinement layer 422 is connected to the second part 420 b , which extends toward the lower electrode 426 , preferably forms an acute angle θ 3 to the projected surface of the insulating plate 420 .
[0055] The relationships between the diameter P4 of a wafer 430 , the projected diameter P2 of the second part 420 b , the diameter P3 of the lower electrode 426 , and the distance P5 from the wafer to the confinement layer 422 and examples thereof may be the same as those described conditions used in the above-described embodiments. The acute angle θ 3 may be the same as the acute angles of the above-described embodiments.
[0056] Compared with the etching apparatuses shown in FIGS. 3 and 4, as described above, since plasma is concentrated in two ways, effective plasma density increases and uniformity of plasma density and etch rate throughout a wafer may be further improved. The diameter of a wafer used in the apparatus shown in FIG. 5 may be the same as the diameters of the wafers 230 and 330 used in the apparatuses shown in FIGS. 3 and 4. Also, power used in the apparatus shown in FIG. 5 may be the same as power supplied to the apparatuses shown in FIGS. 3 and 4. However, the projected diameter P1 of the first part 420 shown in FIG. 5 is preferably larger than the projected diameter D1 of the insulating plate 220 shown in FIG. 3 and the projected diameter N1 of the first part 320 a shown in FIG. 4. Thus, the distance spanned by a plurality of induction coils 414 mounted on a chamber 412 is further increased, thereby increasing magnetic flux even more. In other words, plasma density may be further increased in this embodiment than in the above-described embodiments.
[0057] According to the present invention, a plasma region is preferably made narrower towards a wafer or a processed object than near an insulating plate in order to increase effective plasma density by increasing plasma density at the edge of the wafer. Thus, patterns are formed according to a design, and plasma density may be made uniform near the wafer or the lower electrode, thereby increasing the uniformity of etch rate or deposition rate.
[0058] In the above-described embodiments, the power supply 116 , 216 , 316 , or 426 and the plurality of induction coils 114 , 214 , 314 , or 414 are preferably used to generate plasma. However, microwaves, an electron cyclotron resonance source, or a reactive ion etching source may be used instead.
[0059] Chambers and confinement layers are described as independent components in these embodiments. But the wall of a chamber where a confinement layer is not installed may serve as a confinement layer. Thus, in this case, the wall of the chamber may be designed to so that it narrows toward an electrode where the wafer is positioned. A cylindrical chamber has been described but the spirit of the present invention must not be interpreted as being restricted to this cylindrical chamber. It is apparent to one of ordinary skill in the art that the spirit of the present invention may be applied to a hexahedral, or other geometrically formed, chamber.
[0060] The spirit of the present invention may be applied to an apparatus using plasma where upper and lower electrodes are supplied with power externally, a plasma apparatus where only an upper electrode facing a wafer with an insulating plate that is positioned between the upper electrode and the wafer in a chamber is supplied with power externally, and a magnetic-enhanced reactive ion etching (MERIE) apparatus where only a lower electrode on which a wafer is placed is supplied with power externally.
[0061] A preferred embodiment of the present invention has been disclosed herein and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purpose of limitation. Accordingly, it will be understood by those of ordinary skill in the art that various changes in form and details may be made without departing from the spirit and scope of the invention as set forth in the following claims.
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An apparatus for improving the density and uniformity of plasma in the manufacture of a semiconductor device features a plasma chamber having a complex geometry that causes plasma density to be increased at the periphery or edge of a semiconductor wafer being processed, thereby compensating for a plasma density that is typically more concentrated at the center of the semiconductor wafer. By mounting a target semiconductor wafer in a chamber region that has a cross-sectional area that is smaller than a cross-sectional area of a plasma source chamber region, a predetermine flow of generated plasma from the source becomes concentrated as it moves toward the semiconductor wafer, particularly at the periphery of the semiconductor wafer. This provides a more uniform plasma density across the entire surface of the target semiconductor wafer than has heretofore been available.
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FIELD OF THE INVENTION
The present invention relates to the testing of floating-point arithmetic units, and, more particularly, to the generation of numerical test cases for binary floating-point adders.
BACKGROUND OF THE INVENTION
When developing integrated circuits that perform floating-point arithmetic, designers typically base the representations of floating-point (FP) numbers and the constraints on the results of arithmetic operations on published standards, such as the well-known “IEEE standard for binary floating point arithmetics, An American National Standard, ANSI/IEEE Std 754-1995”. Adherence to such standards guarantees that the circuitry will perform floating-point arithmetic with acceptable and predictable results. Although it is a relatively straightforward task to implement floating-point standards in a floating-point hardware unit, designers usually make modifications in the implementation to improve performance in special cases. Because of this, it is necessary to verify compliance of the finished design to the selected standard. In many instances, errors in floating-point implementation escape detection and find their way into production. Cases such as the well-known Pentium bug show that the verification process in this area is still far from being optimal. The ever-growing demand for increased performance, reduced time-to-market, and decreasing tolerance for errors all combine to make verification increasingly harder. The term “floating-point unit” herein denotes any device or system capable of performing binary floating-point computations by any means including, but not limited to, hardware, firmware, programmable logic arrays, and software.
There are many places problems can occur in the implementation of a floating-point unit, ranging from data problems on single instructions to the correct handling of sequences of instructions in which back-to-back events challenge superscalar implementations. This complexity stems both from the interpretation of the specification (architecture) as well as the peculiarities of the implementation (microarchitecture).
Although there is on-going work to develop formal proofs of adherence to a standard, formal methods are still far from providing a complete answer to the problem. The simulation of test cases (generating the test case data, running the test case on the target floating-point unit, and confirming the accuracy of the result), has traditionally been employed for verification, and therefore remains the foundation of the verification process.
It is the generating of floating-point test cases that is of interest regarding the present invention.
Test Case Generating Background
First, it is clear that there is an enormous, practically unlimited number of different calculation cases to test. In practice then, simulation can be done on only a very small portion of the existing space. Reducing the enormous number of potential test cases to a manageable number that can actually be tested is done through placing suitable constraints on the machine numbers so that the constrained set of machine numbers used in the test will be representative of a particular aspect of testing, but will still constitute a sufficient number of cases for thorough testing. (Constraints are discussed below.)
The rationale behind verification-by-simulation is that one acquires confidence in the correctness of a floating-point unit design by running a set of test cases that encompass a sufficiently large number of different cases, which in some sense is assumed to be a representative sample of the full space. The ability of the floating-point unit design to correctly handle all cases is inferred from the correct handling of the cases actually tested.
To confidently make the above inference requires the building of a set of test cases that covers all special implementations of the floating-point unit design. The problem then becomes one of how best to do this. Since both the architecture specification and the microarchitecture implementation tend to yield a myriad of special cases, generating the test cases using a uniform random distribution over the entire floating-point space would be highly inefficient. For example, it is common that executing an FADD instruction that results in a sum of zero exercises a specific part of the design logic, and therefore such a case should be verified. The probability of randomly generating two floating-point numbers that add to zero, however, is extremely low. Therefore, prior-art random test generators usually possess some internal Testing Knowledge (TK) to bias the test generation towards cases of interest. Such test generators are described in “Model-Based Test Generation For Processor Design Verification” by Y. Lichtenstein, Y. Malka and A. Aharon, Innovative Applications of Artificial Intelligence (IAAI), AAAI Press, 1994; “Constraint Satisfaction for Test Program Generation” by L. Fournier, D. Lewin, M. Levinger, E. Roytman and Gil Shurek, Int. Phoenix Conference on Computers and Communications , March 1995; and “Test Program Generation for Functional Verification of PowerPC Processors in IBM” by A. Aharon, D. Goodman, M. Levinger, Y. Lichtenstein, Y. Malka, C. Metzger, M. Molcho and G. Shurek, 32 nd Design Automation Conference , San Francisco, June 1995, pp. 279–285.
In effect, TK changes the probability distribution of a test space, better adapting that test space to existing knowledge. In a test-generator described in the foregoing references, the TK is in the form of C-language functions (called “generation functions”) which can be added incrementally to the generator, such as by the users themselves. A serious limitation of this prior art approach, however, is that such generation functions are very complex and difficult to write, requiring a deep understanding of the Floating Point unit design. In practice, then, very few generating functions have been added.
Definitions
The following terms and abbreviations are used herein:
Biased exponent the sum of the exponent and a constant “bias” selected so that the biased exponent is always non-negative over the exponent's range. The use of a biased exponent allows representing both positive and negative exponents without requiring a sign. Denormal (a “denormalized number”) a non-zero FP number whose exponent has a reserved value (usually the minimum permitted by the format), and whose explicit or implicit leading bit of the significand is zero. Exponent the component of a binary floating-point number that normally specifies the integer power of 2 which is multiplied by the significand to express the value of the represented number. In certain formats, reserved values of the exponent are used to indicate that the number is denormalized. FP Floating-Point. A binary loating-point number contains a sign, an exponent, and a significand. FxP Fixed-Point Mask a template for a binary number. A mask is a series of characters, each of which represents allowable values for the bit in the corresponding position of the binary number. There is exactly one character in a mask for each bit of the corresponding binary number, with characters in a one-to-one correspondence with the bits. Allowable mask characters include ‘0’, ‘1’, and ‘x’. A ‘0’ character indicates that the corresponding bit of the binary number must be a 0, whereas a ‘1’ character indicates that the corresponding bit of the binary number must be a 1. An ‘x’ character is a “don't care”, meaning that the corresponding bit of the binary number may be either 0 or 1. In a floating-point number, it is possible to specify separate masks for sign, exponent, and significand. NaN (“Not a Number”) a symbolic entity encoded in FP format. Normal (a “normalized number”) a non-zero FP number whose explicit or implicit leading bit of the significand is one. Signficand the component of a binary FP number that consists of a single explicit or implicit leading bit to the left of an implied binary point and a field of fraction bits to the right of the binary point. Even in implementations where the significand's leading bit (to the left of the binary point) is implied and is not explicitly present, the significand still includes that leading bit. Note that a significand differs from a “mantissa” in that a mantissa includes only the fraction field to the right of the binary point, whereas a significand also includes the bit to the left of the binary point. The concept of mantissa may be defined in such a way to include all of the bits of the significand, including the leftmost bit and not only the fraction bits. In this case and for a binary normalized significand, the mantissa would simply be the significand shifted one place to the right, or divided by a scaling factor of 2.
The Set of Machine Numbers
For purposes of illustration, a non-limiting example of a binary floating-point number system is the IEEE standard 754 previously referenced. We assume that three integer constants are given, E min , E max , p. The machine numbers are those which can be represented in the form v=(−1) s ×2 E ×b 0 b 1 b 2 . . . b p−i , where sε{0, 1} represents the sign of v. E, representing the exponent of v, is an integer satisfying E min ≦E≦E max . The bit values are denoted as b i ε{0, 1}, and p is the “precision” of the system. The significand is b 0 b 1 b 2 . . . b p−1 , whose binary point lies between b 0 and b 1 . All machine numbers v that satisfy |v|≧2 Emin are assumed to be normalized (b 0 =1). Those machine numbers which are smaller in magnitude than 2 Emin (including zero) have E−E min and are denormalized (b 0 =0). Thus, each machine number has a unique representation (note that the IEEE standard 754 requires the same uniqueness for single and double formats but not for extended formats).
Binary Representations of Machine Numbers and the Mask Constraint
Machine numbers are herein represented as strings of binary digits (bits). This is true for fixed point numbers as well as for floating point numbers. A mask related to a number is a string of characters of the same length (number of bits) as the number, all of whose characters are in the set {‘0’, ‘1’, ‘x’}. A number and a mask are compatible if all the following conditions are met:
The number and the mask are of the same length (hence each bit of the number corresponds to a specific character of the mask); For each ‘1’ character of the mask, there is a 1 value in the corresponding bit of the number; and For each ‘0’ character of the mask, there is a 0 value in the corresponding bit of the number.
If one or more of the above conditions are not met, the number and the mask are incompatible. Thus, a ‘1’ or a ‘0’ character of the mask determines uniquely the value of the corresponding bit of the number. An ‘x’ character in the mask leaves the corresponding bit value of the number undetermined.
A number is constrained by requiring it to be compatible with a given mask.
Where it is not convenient to represent a floating-point machine number by a single string of bits, it is possible (although not necessary) to split such a representation into a triplet of numbers:
Sign:
A string of one bit, which is 0 for a
‘+' and 1 for a ‘−'. The numerical
value is denoted by s (s = 0 or 1).
Biased exponent:
A string of w bits. This is
interpreted to be a binary integer with
the numerical value e, where 0 ≦ e ≦
2 w − 1. In a non-limiting generalization
from the single and double formats of
the IEEE standard 754, E min = 2 − 2 w−1 ,
E max = bias = 2 w−1 − 1.
Significand:
A string of p bits, b 0 b 1 b 2 . . . b p−1 . Unlike
the single and double formats of IEEE
standard 754, note that b 0 is explicitly
included in the string. Interpreting
the string as a binary number with the
binary point placed between b 0 and b 1 ,
the numerical value of the significand
is S, where 0 ≦ S ≦ 2 − 2 1−p .
Likewise, for convenience it is possible to speak of a triplet of masks corresponding to the above triplet of numbers. For example, it is possible to prepare and manipulate a particular mask as a significand mask.
Note that the above splitting of a floating-point number (or a mask) is for convenience and is non-limiting. In particular, it is still possible to represent a complete floating-point machine number as a single sequence of bits, and it is still possible to speak of a single mask corresponding to such a complete floating-point machine number.
The value v, which corresponds to such a triplet of bit strings is given by:
1. If e=2 w −1 and S≠1, then v is NaN regardless of s. 2. If e=2 w −1 and S=1, then v=(−1) s ×∞ (Infinity). 3. If 0<e<2 w −1 and S≧1, then v=(−1) s ×2 e−bias ×s (Normalized numbers). 4. If e=0 and S<1 then v=(−1) s ×2 Emin ×S (Denormalized numbers and zeroes).
Machine numbers are herein denoted in underlined italics (such as a machine number a ).
Rounding
Mathematically, most numbers in the set of real numbers cannot be represented by a finite number of digits (not even the entire subset of rational numbers), and most of those rational numbers which can be represented by a finite number of digits cannot be represented by the small fixed number of digits in the various floating-point formats. It is common, therefore, that the results of a floating-point operation be adjusted, or “rounded” to fit within the confines of the floating-point representation. The result of a rounding operation is a floating-point number that approximates the precise value that should result from the computation. Rounding, when applied, always introduces an error into the computation, but this error is small enough to be ignored in the vast majority of practical applications.
In practice, the precise value is not necessarily computed, but rather an intermediate result that represents floating-point numbers using a larger number of significand bits than the permitted format of the output (also ref erred to herein as the “output result”). The rounding thus consists of a truncation of the excess digits of the intermediate result, and a possible incrementing of the least significant bit of the significand, with a possible carry of this incrementing to more significant bits of the significand.
There are several different rounding modes, all of which must be taken into account when generating test cases:
round up—round toward the closest floating-point number to the intermediate result that lies between the intermediate result and +∞. round down—round toward the closest floating-point number to the intermediate result that lies between the intermediate result and −∞. round to zero—round toward the closest floating-point number to the intermediate result that lies between the intermediate result and zero. round to nearest/even—round toward the floating point number closest to the intermediate result regardless of the direction. If the intermediate result lies exactly halfway between the nearest larger floating-point number and the nearest smaller floating-point number, choose the nearest floating-point number whose least significant significand bit is zero (“even”).
Coverage
How does one know that a certain set of tests is sufficient? This question is related to the notion of coverage, that is, to the comprehensiveness of the set related to the target floating-point unit. Coverage models are usually defined, and the set of teats should fulfill all the existing requirements. A coverage model constitutes a set of related cases. Coverage modeling is discussed in “Software negligence and testing coverage” by C. Kaner, Proceedings of STAR 96: the Fifth International Conference, Software Testing, Analysis and Review , pages 299–327, June 1996; and “User defined coverage—a tool supported methodology for design verification” by R. Grinwald, E. Harel, M. Orgad, S. Ur, and A. Ziv, Proceedings of the 35 th Design Automation Conference ( DAC ), pages 158–163, June 1998.
As an example, a common coverage model—albeit one that is far from trivial to fulfill—requires enumerating all major IEEE Floating Point types simultaneously for all operands of all FP instructions. For a given instruction with three operands, say ADD, this potentially yields in the order of a thousand (10 3 ) cases to cover, assuming 10 major FP types (±NaN's, ±Infinity, ±Zero, ±Denormal, ±Normal). This model can be further refined by adding more FP types, such as Minimum and Maximum Denormals, and so forth. Obviously, not all cases are possible (for example, the addition of two positive denormal numbers cannot reach infinity), so that the actual number of cases is in fact lower than the size of the Cartesian product. A coverage model, or the set of all coverage models, is really an attempt to partition the set of all calculation cases in such away that the probability distribution should be similar for all subsets.
A Generalized Test-Case Generator
Consider an automatic test generator whose input is the description of a coverage model, and whose output is a set of tests covering that model. A coverage model is defined by specifying a set of different constraints to be fulfilled, where each constraint corresponds to a particular task targeted by the coverage model. More precisely, a coverage model will have the form of a sequence of FP instructions, with sets of constraints on the input operand(s), the intermediate result(s), and the results of the participating instructions. Covering the model then requires providing a set of tests which display the instruction sequence, and which possesses the property that each constraint is satisfied by at least one test of the set. The general appearance of a single instruction constraint is of the following form:
FPinst (Op 1 in Pattern 1 ) (Op 2 in Pattern 2 ) (IntRes in Pattern 3 ) (Res in Pattern 4 ) (1)
where FPinst is a generic floating point instruction with two input operands (Op 1 and Op 2 ), one intermediate result (IntRes), and one output result (Res). The case of two input operands and a single intermediate result is used here for simplicity, but of course generalization to any number of such parameters is possible.
A Pattern is a construct representing the logical union (∪) among sets of FP numbers. The sets serve as constraints defining (in fact limiting) the allowable FP numbers for each term of expression (1). Patterns have the general following form:
Pattern=Set 1 ∪Set 2 ∪ . . . ∪ Set N (2)
where each Set 1 is a set of FP numbers. Each task of the coverage model corresponds to a specific selection of Set i for each Pattern. Covering the task reduces then to select a data—tuple where each individual datum belongs to the corresponding selected Set i . Thus, the number of different tasks originated from a single such instruction is the product of the number of Sets for each participating Pattern. The number of tasks for a sequence is the product of the number of tasks for each individual Instruction.
There are different kinds of constraints on FP numbers:
Ranges—constraints on the upper and lower limits of a machine number or element of number triplet (for example, an exponent between 0 and 2); Weights—constraints on the limits of the number of bits of value 1 within a machine number or element of a number triplet (for example: at least 1 bit set in the significand); Run-length—constraints on the lengths of continuous streams of 1's and/or 0's (for example: a stream of at least 45 consecutive 1's in the significand); and Masks—constraints on individual bits of a machine number (described herein in detail).
It is also possible to specify a set for which the selected value should be a function of the value previously selected for another input operand. For example, a selected exponent can be at a distance of at most 2 from the exponent selected for the previous input operand. Set operations (intersection, union, complement, of same and different set types) are also possible.
For a generalized test-case generator, any architecture resource which might influence FP instruction's results is settable as an input. For example, in the non-limiting case of IEEE standard architecture, this applies to Rounding Modes and Enabled Flags.
A generalized test-case generator solves constraints that are derived from set restrictions on instruction operands. Given a restriction, the generator ideally seeks a random instance that solves the restriction, where the solutions are uniformly distributed among the set of all solutions. In practice, the complexity involved is sometimes overwhelming, especially for complex or multiple restrictions. In such cases, the generator at least ensures that each solution has a reasonable probability of being selected. As described above, constraints can be given on the input operands, the output or even on both simultaneously. It should be clear that there is a significant leap in complexity involved in solving constraints on outputs. Indeed, in contrast to the case of the input operands, the constraint on outputs includes the instruction semantics. However, even output constraints are usually solvable analytically In reasonable time complexity. Constraint restrictions start to become largely intractable when simultaneous constraints are requested on both input operands and outputs. For example, it is largely unclear how to find an instance in which the result of a MUL instruction has at least 45 bits set in its significand and the inputs are restricted by specific ranges or masks. Such a case might seem artificial, but it is often the case that cases such as this one are important to check due to specific implementation methods. Moreover, during the implementation itself, it is sometimes important to explore whether some cases are possible at all—it is desirable to know if a solution does not exist. Knowing that some cases can be neglected can be critical in optimizing the microarchitecture. In fact, in many cases, it can be shown that the constraint problem is NP-Hard. Thus, the generalized test case generator's approach for these problems should be heuristic, mixing probabilistic, search spaces and semi-analytic algorithms. Some important cases of simultaneous constraints, however, are solvable analytically, including, for example, Range constraints or Mask constraints on all operands for the FP ADD instruction.
Test Generation Via Masks
The present inventors have realized that it is possible to advantageously specify the generation of test cases using masks to constrain the floating-point numbers of the test cases, as described previously. Masks are an important way of defining sets of floating-point machine numbers by providing constraints on the bits of those numbers.
There are a number of important advantages in utilizing masks for specifying constraints in the generating of test cases:
Masks are easy to visualize, understand, and manipulate. Using masks does not require the user to develop any complicated algorithms or to write any software code, as is required for prior-art generation functions. Masks can be easily created to describe a wide range of machine numbers having specific properties of interest to floating-point unit designers. It is common for an implementation to treat a specific bit, or set of specific bits, in a particular manner, and masks are a natural means to introduce a bias towards numbers having specific bits set to prescribed values, while the values of other bits are assigned randomly. At the architectural level, masks allow defining all the IEEE generic types of FP numbers and symbolic objects: Normals, Denormals, infinities, zeroes, NaN's, and so forth. Thus, a coverage model handling all types of numbers and symbols is expressible through masks. Although masks are not as general as the range, weight, or run-length constraints previously described, it is relatively straightforward to produce a finite (though possibly large) mask set which incorporates and expressed all the properties of a given range, weight, or run-length constraint.
FIG. 1 illustrates the development of mask-constrained test cases. (Note that in this particular illustration, a floating-point number is taken as being associated with a single mask, as opposed to a triplet of masks as previously discussed.) Starting with a test concept 101 , a specified floating-point operation along with some Testing Knowledge 102 is compiled into an operation, mask, and rounding specification 103 , which selects a rounding mode for the given floating-point operation and a set of suitable masks 104 , which includes:
Mask(s) for input operand(s); and Mask for the output result.
Floating-point operation, rounding mode, and mask set 104 are input to a floating-point test case generator 105 . Floating-point test case generator 105 in turn outputs the floating-point operation, rounding mode, and a set of machine numbers 106 , which includes:
Machine number(s) for the input operand(s); and Machine number for the output result.
Floating-point operation, rounding mode, and machine number set 106 constitute a solution 107 . If, however, there exists no set of machine numbers 106 compatible with mask set 104 (which is possible, such as when the specified result mask is incompatible with the input operand masks given the specified floating-point operation), then there is no solution. In this case, solution 107 is a determination that no solution actually exists.
If there exists a set 106 , the machine numbers thereof, along with the floating-point operation and rounding mode, would then be input to the target floating-point unit (not shown) to see if how the unit performs for the given floating-point operation on the given inputs, and if the unit produces the given output result. If the target floating-point unit properly duplicates the machine number for the output result as given in set 106 , then the unit has passed this particular test. Otherwise, if the target unit does not properly duplicate the machine number for the output result as given in set 106 , there is a design error in the unit which must be corrected. Likewise, if solution 107 determines that there is in fact no solution, it may be possible to test the target unit to verify that the unit in fact does not perform any computation that results in a set of machine numbers corresponding to the masks given in set 106 , because doing so also indicates a design error in the unit. Thorough testing requires exercising the target floating-point unit with a large number of such test cases for a variety of conditions.
As an example (based on the concepts in IEEE standard 754), consider a hypothetical binary floating point format of eight bits, whose structure is seeeffff. Namely, there is one bit for a sign, three bits for a biased exponent and four bits for a fraction. In analogy with the IEEE formats single and double, the significand has five bits, E min =−2, E max =bias−3. Given three masks M a =0100x101, M b =001x1011, and M c =010xx10x, the solution requires three floating point numbers a , b , and c , which are compatible with the respective masks, such that c =round ( a + b ). Assuming that round stands for round to nearest/even, one solution is a =01000101, b =00101011, and c =01001100.
In the scheme illustrated in FIG. 1 , it is necessary to construct floating-point test-case generator 105 with the following properties in mind:
All valid solutions must have roughly the same probability of being produced by the test-case generator; and in particular, The solution set must not arbitrarily exclude any valid solution. In other words, every valid solution must have a non-zero probability of being selected.
Currently, however, there are no such mask-constrained floating-point test-case generators available, even for a restricted set of floating-point operations such as addition and subtraction. In order to create a floating-point test-case generator, it is necessary to have as a minimum, a floating-point test-case generator for addition and subtraction, which can solve the hollowing problem: Given masks for three machine numbers and a rounding mode, generate machine numbers a , b , and c , which are compatible with the given masks and satisfy c =round( a ± b ), where round corresponds to the given rounding mode.
There is thus a need for, and it would be highly advantageous to have, a mask-constrained floating-point test case generator for floating-point addition and floating-point subtraction which has the desired properties listed above. This goal is met by the present invention.
SUMMARY OF THE INVENTION
The present inventors have recognized that the lack of a practical framework for generating constrained, meaningful test cases is a major deficiency in the prior art, and represents the principal obstacle to efficient verification. The present invention, therefore, approaches this problem from the overview presented in the following sections.
It is an object of the present invention to solve the following problem: Given masks for three machine numbers and a rounding mode round, generate machine numbers, a , b , c , which are compatible with the masks and satisfy c =round( a ± b ).
It is an object of the present invention to develop a method for generating three floating-point machine numbers a , b , and c corresponding to three given masks M a , M b , and M c , and a rounding mode round, such that c =round( a + b ), where either or both a and b may be positive or non-positive.
It is also an object of the present invention that all valid solutions have roughly the same probability of being produced by the method, and that no valid solutions be excluded.
It is moreover an object of the present invention that the method support general binary floating-point standards, including but not limited to IEEE standard floating-point arithmetic when generalized to include all allowed FP format sizes (such as 32 bits, 64 bits, 80 bits, 128 bits). With respect to this particular goal, it is noted that the innovations of the present invention are not necessarily limited to binary implementations, but can be applied in other number systems as well. Although binary systems are of primary importance, because current floating-point standards are expressed explicitly in terms of binary numbers, it is understood that the present invention is not limited to binary arithmetic, and the details of the embodiments herein presented are to be taken as non-limiting examples.
It is further an object of the present invention to develop a system for implementing the method.
The basic problem may be split into two sub-problems, which may be solved by two generators of machine numbers, respectively:
Floating-point generator for addition: Given six masks, for biased exponents and for significands, M ea , M Sa , M eb , M Sb , M ec , M Sc , the generator either generates three non-negative machine numbers, a , b , c , whose biased exponents and whose significands are compatible with the corresponding masks and satisfy, c =round( a + b ), or states that there is no solution. Floating-point generator for subtraction: Given six masks, for biased exponents and for significands, M ea , M Sa , M eb , M Sb , M ec , M Sc , the generator either generates three non-negative machine numbers, a , b , c , whose biased exponents and whose significands are compatible with the corresponding masks and satisfy, c =round( a − b ), or states that there is no solution.
Note that when the problem is reduced to the two cases above, the three machine numbers, a , b , and c , are all non-negative. In the case of the floating-point generator for subtraction, the values assigned to a and b are interchanged if necessary so that a ≧ b . Note also that in the case of the floating-point generator for subtraction, where a ≠ b it is possible to exercise the target floating-point unit with two test cases resulting from a single solution found by the generator: one test case is simply c =round( a − b ), where c is positive; and the other test case is c =round( b − a ), where c is negative. As far as the floating-point test-case generator is concerned, these are mathematically identical and do not require a separate method of solution. From the standpoint of verification testing of the target floating-point unit, however, they are distinct problems, and the successful passing of one test by the target floating-point unit does not necessarily imply the successful passing of the other test.
The method of the present invention solves the above problem for simultaneous mask constraints. That is, there is a mask constraint on both input operands a and b , and on the output result c for any specified rounding mode and for the floating-point operations FADD and FSUB. It is noted that the distinction between addition and subtraction can be implied in the sign of the operand b : If b <0, a subtraction operation is implied; otherwise, an addition operation is implied. It is further noted that a single solution found by the binary floating-point test-case generator of the present invention can be verified on the target floating-point unit for both FADD and FSUB by adjusting the sign of one of the input operands. That is, given the solution a , b , and c where c =round( a + b ), it is possible to verify FADD on the floating-point unit for a , b , and c , and it is also possible to verify FSUB on the floating-point unit for a , − b , and c . The internal implementation of FADD in the target floating-point unit can be structurally different from that of FSUB, justifying a separate verification pass, but the identical result c should be output in both cases.
Rounding Modes Needed
In the general case, there are the following rounding modes:
roundε{round down, round up, round toward zero, round to nearest/even} (3)
However, since the problem has been reduced to cases where the three machine numbers are all non-negative, it is possible to omit, without loss of generality, the round toward zero mode. Since all non-zero machine numbers will be positive, this mode is equivalent to round down.
Novelty
There are several novel aspects of the present invention:
The present invention goes beyond the employment of masks for expressing floating-point machine number constraints to include a novel use of masks for controlling the stream of carry bits created during the floating-point addition operation. In addition to providing a key portion of the method, this also enriches the verification process by allowing a floating-point unit to be exercised through different carry configurations. The present invention discloses a fixed-point generator which has a number of unexpected uses in various places throughout the floating-point test-case generation.
Notational Conventions
The following notation is employed herein in the context c =round ( a ± b ):
a , b , c floating-point machine numbers e i biased exponent E i unbiased exponent M i mask n boundary index, the position of the leftmost 2 in a carry sequence N number of bits in a fixed-point machine number p number of bits in a significand (including the most significant bit) q maximum definite binary point shift, usually comparable in magnitude to p (shifts greater than q are considered indefinite) q i biased exponent shift
q a =e c −e a , q b =e c −e b (1)
Q i unbiased exponent shift
Q a =E c −E a , Q b =E c −E b (2)
S i significand w number of bits in a biased exponent x, y, z fixed-point machine numbers
FIG. 2 is a block diagram of a floating-point addition/subtraction test-case generator according to the present invention. A mask set 201 is input into a processing unit 202 , which generates test-cases in an output 250 , which, as previously noted, may be either floating-point machine numbers compatible with mask set 201 and a specified rounding mode (not shown) or the case of “no solution”. In the non-limiting example presented herein, processing unit 202 includes a q a , q b /q b , q c selector 205 whose output goes to a biased exponent generator 210 , which includes a definite biased exponent generator 215 and an indefinite biased exponent generator 220 . For addition, q a , q b /q b , q c selector 205 selector selects q a and q b , whereas for subtraction q a , q b /q b , q c selector 205 selector selects q b and q c . Then, a Q a , Q b /Q b , Q c calculator 225 computes Q a and Q b for addition or Q b and Q c for subtraction, and sends them to a significand generator 230 , which includes an addition significand generator 235 and a subtraction significand generator 240 . Both biased exponent generator 210 and significand generator 230 rely on a fixed-point generator 245 in making their respective computations. Finally, the output of biased exponent generator 210 and significand generator 230 are combined to output solution set 250 .
Note that, in FIG. 2 , biased exponent generator 210 is a non-limiting example of a more general exponent generator that need not be restricted to biased exponents only. Because an unbiased exponent shift is calculated, it is also possible to conceptualize the system of FIG. 2 in terms of such general exponent generator.
Given the selected and calculated values for q a , q b , Q a , Q b for addition (or q b , q c , Q b , Q c , in the case of subtraction), it is possible to produce the biased exponents and the significands independently, by invoking number generators such as those shown in FIG. 2 , and defined as follows:
Definite biased exponent generator 215 performs the following: Given the two non-negative integers q 1 , q 2 , with q 1 ε{0, 1}, and three masks of length w, M 1 , M 2 , M 3 , for the biased exponents, definite biased exponent generator 215 either generates and outputs three biased exponents e 1 , e 2 , e 3 , which are compatible with the respective masks and satisfy e 3 =e 1 +q 1 =e 2 +q 2 , or outputs that no solution exists.
Indefinite biased exponent generator 220 performs the following: Given the two non-negative integers q 1 , q 2 , with q 1 ε{0, 1}, and three masks of length w, M 1 , M 2 , M 3 , for the biased exponents, indefinite biased exponent generator 220 either generates an integer q 2 and three biased exponents e 1 , e 2 , e 3 , which are compatible with the respective masks and satisfy e 3 =e 1 +q 1 =e 2 +q 2 , such that q 2 >q, or outputs that no solution exists.
Addition significand generator 235 performs the following: Given two non-negative integers Q a , Q b , one of which is 0 or 1, three masks of length p for the significands, M Sa , M Sb , M Sc , and a rounding mode, roundε{round down, round up, round to nearest/even}, addition significand generator 235 either generates three significands S a , S b , S c which are compatible with the respective masks and satisfy S c =round (2 −Qa S a +2 −Qb S b ), or outputs that no solution exists.
Subtraction significand generator 240 performs the following: Given two non-negative integers Q b , Q c , one of which is 0 or 1, and three masks of length p for the significands, M Sa , M Sb , M Sc , and a rounding mode, roundε{round down, round up, round to nearest/even}, subtraction significand generator 240 either generates three significands S a , S b , S c , which are compatible with the respective masks and satisfy 2 −Qc S c =round (S a −2 −Qb S b ), or outputs that no solution exists.
FIG. 3 is a simplified block diagram of fixed-point generator 245 (as also appears in FIG. 2 ) according to the present invention. A mask set 303 containing masks M x , M y , and M z , for three fixed-point machine numbers x, y, and z is input into fixed-point generator 245 . In additions a mask M c 305 for the carry stream is also input. Note that M x , M y , and M z each have N characters corresponding to the N bits of x, y, and z, whereas M c has N+1 characters. Based on the inputs, fixed-point generator 245 outputs a solution 307 , which either contains a set of three fixed-point machine numbers x, y, and z which are compatible with mask set 303 (M x , M y , and M z ) and mask 305 (M c ); or which is the case of “no solution”.
It is to be noted that all of the generators of the present invention generate a solution that is in effect randomly selected from the complete set of valid solutions, and if the set of valid solutions is empty, the case of “no solution” is output instead. It is not required that a generator output all of the valid solutions, but only a single solution, provided that at least one valid solution exists. It is also not required that a generator be able to determine how many valid solutions there are. The generators, however, do not arbitrarily exclude any valid solution. That is, there is a non-zero probability that any specific valid solution will be generated. Subsequent operation of a generator will usually generate a different, randomly-generated solution. If the complete set of valid solutions is of high order, then it will be overwhelmingly probable that repeated operations of a generator will result in the output of distinct solutions, so repetitions of identical solutions are normally rare.
Solution-Seeking Method
As will be discussed in detail below, the generators make extensive use of a solution-seeking method illustrated in FIG. 4 . In the present invention, the solution-seeking method is used in a number of places to seek a solution that may satisfy any of a variety of specified mathematical conditions. The solution that is sought may represent intermediate results within processing unit 202 ( FIG. 2 ) which are used in constructing floating-point test-case solution 250 , as well as floating-point test-case solution 250 itself.
As illustrated in FIG. 4 , associated with the method is a finite list of input choices 401 which contains a set of parameters for the solution being sought. Other parameters may be applied, as discussed below. The method begins at a start block 403 , immediately after which a decision point 405 checks to see if list 401 is empty. If so, then there are no available parameters for the solution, indicating that there is no solution, in which case at an output block 407 the method terminates with the output of the “no solution” case. Otherwise, in a selection block 409 one of the elements of list 401 is selected at random. Then, in a solution-searching block 411 a solution is sought utilizing the selection from the list. A decision point 413 checks to see if a valid solution has been found. If so, the solution is output in a block 415 , and the method terminates. Otherwise, in a block 417 the selection made in block 409 is erased from list 401 , and the method resumes once again at decision point 405 . Ultimately, because list 401 is finite, either a valid solution will be returned in block 415 , or the “no solution” case will be returned in block 407 .
The following points are noted regarding solution-seeking block 411 :
The inner details of block 411 depend on the specific details of the problem for which a solution is sought; A valid solution may depend on additional parameters within block 411 besides the selection made from list 401 ; and Block 411 may encapsulate one or more instances of this same solution-seeking method—that is, the entire solution-seeking method may be used recursively within block 411 , such that another set of all the elements shown in FIG. 4 appear within block 411 . For example, the floating-point addition test-case generator as shown in FIG. 2 utilizes a solution-seeker as shown in FIG. 4 , whose list 401 contains a finite number of q a , q b pairs. But within the floating-point addition test-case generator there is addition significand generator 235 which itself utilizes a solution-seeker as shown in FIG. 4 , whose list 401 contains a finite number of elements (“tails triplets”) which are based on a Q a , Q b pair calculated from the q a , q b pair selected from the floating-point addition test-case generator's list 401 . This is explained in detail below, but is mentioned here to show how the solution-seeker of FIG. 4 may be used recursively. Block 411 and decision-point 413 may be repeated sequentially within the loop shown in FIG. 4 , with found solutions from one block sent to the next such block as an intermediate or partial solution.
Example of a Solution
Here is an example of a triplet of masks which may be used as input to a binary floating-point addition test-case generator according to the present invention, illustrated in the non-limiting case of IEEE standard 754 double precision (1 sign bit, 11 biased exponent bits, 52 fraction bits, for a total of 64 bits):
The furnished masks specify two denormal floating point numbers as input operands for addition, and the mask for the sum specifies a normalized floating-point number.
s
e
S
M a
0
00000000
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
000
xxxxxxxxxxxxxxxx
M b
0
00000000
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
000
xxxxxxxxxxxxxxxx
M c
0
00000000
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
001
xxxxxxxxxxxxxxxx
One possible solution is:
s
e
S
a
0
00000000
1111111111111111111111111111111111111111
000
111111111111
b
0
00000000
0000000000000000000000000000000000000000
000
000000000001
c
0
00000000
0000000000000000000000000000000000000000
001
000000000000
Another solution is:
s
e
S
a
0
00000000
1111100000000000000000000000000000000000
000
000000000000
b
0
00000000
0001010101010101010101010101010101010101
000
010101010101
c
0
00000000
0000110101010101010101010101010101010101
001
010101010101
The complexity of the method according to the present invention is polynomial, and tests confirm that it operates efficiently and quickly: in practice, solutions are found almost immediately for a large variety of instances.
It will also be understood that the system according to the invention may be a suitably programmed computer. Thus, the invention contemplates a computer program being readable by a computer for executing the method of the invention. The invention further contemplates a machine-readable memory tangibly embodying a program of instructions in data storage executable by a machine for performing the method of the invention. The invention moreover contemplates a machine-readable memory tangibly embodying a program of instructions in data storage executable by a machine for emulating the system of the invention.
According to the present invention there is provided a system for generating floating-point test-cases for verifying the operation of a floating-point arithmetic unit, the system including a processing unit which includes: (a) an exponent generator, for generating floating-point exponents; (b) a significand generator, for generating floating-point significands; and (c) a fixed-point generator coupled to the exponent generator and to the significand generator; wherein the processing unit is configured to receive a specified arithmetic operation selected from a group that includes addition and subtraction, a specified rounding mode, a first input operand mask, a second input operand mask, and an output result mask; and wherein the processing unit is configured to output a set of floating-point numbers which includes a first input operand compatible with the first input operand mask, a second input operand compatible with the second input operand mask, and an output result compatible with the output result mask; and wherein the output result corresponds to the specified arithmetic operation on the first input operand and the second input operand for the specified rounding mode.
In addition, according to the present invention there is provided a method of seeking a solution, if a solution exists, to a specified mathematical condition, wherein the solution is used in constructing a floating-point test-case for verifying the operation of a floating-point arithmetic unit, wherein a complete generated test case is a set of floating-point numbers for a specified arithmetic operation selected from a group including addition and subtraction, and for a specified rounding mode, and wherein a generated test case includes a first input operand, a second input operand, and an output result; and wherein the first input operand is compatible with a first input operand mask, the second input operand is compatible with a second input operand mask, and the output result is compatible with an output result mask; the method including the steps of: (a) preparing a list of choices upon which the solution is based; (b) testing whether the list of choices is empty; (c) outputting, if the list of choices is empty, that no solution exists; (d) randomly choosing, if the list of choices is not empty, a choice of the list as a selection; (e) searching for a solution to the specified mathematical condition, based on the selection; (f) outputting, if the searching was successful, the solution; (g) erasing, if the searching was not successful, the selection from the list; and (h) repeating step (a) through step (g) until outputting occurs.
Furthermore, according to the present invention there is provided a method of generating a set of fixed-point numbers containing a first addend, a second addend, and a sum, wherein the first addend is compatible with a first addend mask, the second addend is compatible with a second addend mask, the sum is compatible with a sum mask, and wherein the addition of the first addend and the second addend results in a carry sequence of carry bits, wherein each carry bit has a unique index in the carry sequence, wherein the carry sequence is compatible with a carry sequence mask and wherein each carry bit has a value in the group consisting of 0, 1, and 2, and wherein there exists a boundary index in the carry sequence corresponding to the lowest index of a carry bit having the value 2; the method including the steps of: (a) constructing a list of possible boundary indices; (b) testing whether the list is empty; (c) outputting, if the list is empty, that no solution exists; (d) randomly choosing, if the list is not empty, a boundary index from the list as a selection; (e) searching for a carry sequence based on the selection, which is compatible with the carry sequence mask; (f) erasing, if the searching was not successful, the selection from the list; (g) constructing, if the searching was successful, a first addend compatible with the first addend mask, a second addend compatible with the second addend mask, and a sum compatible with the sum mask; (h) outputting the first addend, the second addend, the sum, and the carry sequence; and (i) repeating step (a) through step (h) until outputting occurs.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:
FIG. 1 illustrates the progression from test concept to mask specification to the finding of a solution, or the determination that there is no solution.
FIG. 2 is a block diagram of a floating-point addition/subtraction test-case generator according to the present invention.
FIG. 3 is a simplified block diagram of a fixed-point generator according to the present invention.
FIG. 4 is a flow-chart showing the steps of a generalized solution-seeking method according to the present invention.
FIG. 5 graphically shows the finding of a solution for the indefinite biased exponent generator.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The principles and operation of a floating-point addition/subtraction test-case generating method and generator according to the present invention may be understood with reference to the drawings and the accompanying description.
Outline of the Method
As was stated earlier, the problem of generating floating point numbers, satisfying c =round( a ± b ), may be divided into two cases: addition of non-negative machine numbers and subtraction of non-negative machine numbers.
Consider first the addition case. Namely, let c =round( a + b ), where a , b , c are non-negative machine numbers. The biased exponent shifts are denoted q a =e c −e a and q b =e c −e b , where e a , e b , e c are the biased exponents. It is not difficult to see that q a , q b are non-negative integers, one of which must be either 0 or 1. Likewise, the unbiased exponent shifts are denoted Q a =E c −E a and Q b =E c −E b , where E a , E b , and E c are the unbiased exponents. It is easy to see that Q a , Q b are also non-negative integers, one of which must be either 0 or 1. Usually Q a =q a , Q b =q b but this is not always so. For addition there are the following five cases:
e a >0, e b >0, e c >0: Q a =q a , Q b =q b (6)
e a =0, e b >0, e c >0: Q a =q a −1 , Q b =q b (7)
e a >0, e b =0 , e c >0: Q a =q a , Q b =q b −1 (8)
e a =0 , e b =0, e c >0: Q a =q a −1, Q b =q b −1 (9)
e a =0, e b =0, e c =0: Q a =q a , Q b =q b (10)
For subtraction the outcome is similar: With c =round( a − b ) there are q b =e a −e b , q c =e a −e c , Q b =E a −E b , and Q c =E a −E c , where one of q b , q c is either 0 or 1, and one of Q b , Q c is either 0 or 1. Thus, there are an additional five cases:
e c >0, e b >0, e a >0: Q c =q c , Q b =q b (11)
e c =0 , e b >0, e a >0: Q c =q c −1 , Q b =q b (12)
e c >0, e b =0, e a >0: Q c =q c , Q b −q b −1 (13)
e c =0, e b =0, e a >0: Q c =q c −1, Q b =q b −1 (14)
e c =0, e b =0, e a =0: Q c =q c , Q b =q b (15)
As illustrated in FIG. 2 for the non-limiting example of processing unit 202 , after mask set 201 has been given, the generation of machine numbers is started by selector 205 , which selects values for q a , q b for addition, or q b , q c for subtraction. With known values for these numbers, it may be possible for biased exponent generator 210 to find valid solutions for the biased exponents, after which calculator 225 can calculate Q a , Q b for addition or Q b , Q c for subtraction. For addition, calculator 225 relies on Case (6), Case (7), Case (8), Case (9), or Case (10), above, as appropriate. Likewise, for subtraction, calculator 225 relies on Case (11), Case (12), Case (13), Case (1), or Case (15), above, as appropriate. Based on this, significand generator 230 is able to complete the process for output 250 .
The addition/subtraction test-case generator illustrated in FIG. 2 makes use of the solution-seeking method illustrated in FIG. 4 . In order to do this, it is first necessary to produce list 401 for q a , q b in the case of addition, or q b , q c in the case of subtraction. Table 1 shows a list of such pairs:
TABLE 1
q a , q b Pairs
q a
0
0
1
1
0
0
. . .
0
0
1
1
. . .
1
1
2
3
. . .
q
>q
2
3
. . .
q
>q
q b
0
1
0
1
2
3
. . .
q
>q
2
3
. . .
q
>q
0
0
. . .
0
0
1
1
. . .
1
1
Note that, while Table 1 is expressed as q a , q b pairs (for addition), the pairs are equally valid as q b , q c pairs (for subtraction). Solutions for pairs 0, >q; 1, >q; >q, 0; and >q, 1 are handled by indefinite biased exponent generator 220 ( FIG. 2 ). Solution for all other pairs are handled by definite biased exponent generator 215 . The exact value of q in the table is not specified, but if a convenient value close to p is selected, there will be approximately 4p pairs in Table 1. Within the floating-point test-case generator, as shown in FIG. 2 , calculator 225 calculates Q a , Q b for addition or Q b , Q c for subtraction, as may be necessary for internal finding of significand solutions, as discussed below.
The solution-seeker of FIG. 4 is then invoked, with solution-searching block 411 set up to seek solutions according to the following (making reference to FIG. 2 ):
1. use either definite biased exponent generator 215 or indefinite biased exponent generator 220 as appropriate (according to the above criteria for the input pair) to seek a solution triplet for e a , e b , and e c that is compatible with the exponent masks of mask set 201 ; and 2. compute Q a , Q b /Q b , Q c via calculator 225 and use either addition significand generator 235 or subtraction significand generator 240 as appropriate to seek a solution triplet for S a , S b , and S c that is compatible with the significand masks of mask set 201 .
If either one or both of the above solutions do not exist, decision-point 413 ( FIG. 4 ) branches to erase block 417 . Otherwise, if both of the above solutions exist, the method has found a valid solution triplet e a , S a ; e b , S b ; and e c , S c , having both exponents and significands, and therefore decision-point 413 branches to output block 415 .
The Fixed-Point Generator
As noted previously, several of the computations required for a floating-point generator according to the present invention require a fixed-point generator.
In implementing significand generator 230 ( FIG. 2 ), for example, note that, since Q a , Q b (or Q b , Q c ) are known (as output from calculator 225 ), it is possible to shift the significands until they are properly aligned so that they have identical exponents, and then add (or subtract) them precisely the way fixed-point numbers are added (or subtracted). To do this, it is necessary to have a fined-point generator.
Before specifying the exact function of the fixed-point generator, first consider the process of adding two positive binary integers, x+y=z: The addends in this process are x and y, and the sum is z. The process starts by adding the rightmost (least significant) bits of x and y. If the sum is less than 2 then it is equal to the rightmost bit of z and there is no carry. If the sum is not less than 2, there is a carry of 1. Next, the carry is added along with the following bits of x and y. Once again, if the sum is less than 2, there is no carry. If the sum is not less than 2, there is a carry of 1. This is repeated through the final (most significant) bits of x and y. Thus, during the addition process, a sequence of carries, each of which is either 0 or 1, is generated. The carry sequence represents the carries from the successive digits of the addends. Note that the fixed-point generator considers only the addition of two numbers.
In the following discussion, the bit-numbering convention for a binary fixed-point number containing N bits is as follows: the leftmost (most significant) bit is assigned an index value of m=0, and the rightmost (least significant) bit is assigned an index value of m=N−1.
If the values of the bite of the addends are x m −i, y m =j and those of the sum are z m =k, then there is the equation:
i+j+C m+1 =k+ 2 C m ( m= 0, 1 , . . . , N− 1) (16)
where C m is the carry sequence, representing the carries resulting from the addition of successive digits of the addends. The bits themselves always are such that i, j, kε{0, 1}. For the carry, it is also normally the case that C m ε{0, 1}. However, a round up process may add an additional 1 to the carry and produce an effective carry of 2, so for this reason it is convenient to allow C m , C m+1 ε{0, 1, 2}. Note that whereas (m=0, 1, . . . , N−1) for the bits of the fixed-point numbers, (m=0, 1, . . . , N) for the carry sequence. C m is the carry out of bit m and into bit m−1, where bit m and bit m−1 actually exist. For example, C N is the carry into bit N−1 only, because there is no bit N. Likewise, C 0 is the carry out of bit 0 only, because there is no bit − 1 . C 0 and C N are boundary values, and usually both have a value of zero. For generality, however, it is possible that C 0 ≠0 and C N ≠0.
It is important to note that, while C m , C m+1 ε{0, 1, 2}, there are restrictions on the appearance of a value of 2 in a carry position;
C m =2 C m+1 =2 (17)
because the only way a carry position (in m) value can be 2 is if the previous carry position (in m+1) is 2. Restriction (2) can be rewritten as
C m+1 <2 C m <2 (18)
And
C m+1 =2 C m ≧1 (19)
because even if i+j=0 in position m, a carry of 2 in position m+1 will propagate at least to a value of 1 in position m.
Because of Restrictions (17), (18), and (19), it is easy to see that if there are any 2's in the carry sequence, they are all grouped together to the right, and that there is a 1 to the immediate left of the leftmost 2. For example, the following is a possible carry sequence into a 16-bit sum:
0 1 1 0 1 0 1 2 2 2 2 2 2 2 2 2
The following, however, are not possible carry sequences:
0 1 1 0 1 0 1 2 2 2 2 2 2 2 2 1—violates Restrictions (17)/(18)
0 1 1 0 1 0 0 2 2 2 2 2 2 2 2 2—violates Restriction (19).
Thus although C m , C m+1 ε{0, 1, 2} implies that there are 9 (=3 2 ) different combinations for the pair (C m ,C m+1 ), there are in actuality only 6 different allowable combinations, because the pairs (0,2), (2,0), and (2,1) are ruled out by Restrictions (17), (18), and (19), leaving only the following set of possible pairs for (C m ,C m+1 ):
(C m , C m+1 )ε{(0,0), (0,1), (1,0), (1,1), (1,2), (2,2)} (20)
Set (20) is important in the construction of carry sequences. An innovation of the present invention for solving the fixed point generator problem is to first construct the sequence C m , and only later construct the bits of x, y, and z. This is discussed in detail below.
The input to the fixed point generator includes masks of length N: M x , M y , M z , of the form described earlier, for the numbers x, y, z. The input also includes a mask, M c , of length N+1, which corresponds to the sequence of carries. This carry sequence mask can include the characters ‘0’, ‘1’, ‘2’, and ‘x’, where in analogous fashion to the previously-defined mask characters, ‘0’, ‘1’, and ‘2’ completely specify the value of the corresponding carry, whereas an ‘x’ leaves the corresponding carry undetermined.
The fixed point generator is then defined as follows:
Fixed-point generator: Given three masks, M x , M y , M z , of length N for three fixed-point binary numbers of N bits each, and given one mask, M C , of length N+1 for a corresponding carry sequence, the fixed point generator either generates three fixed-point binary numbers x, y, z, which satisfy z=x+y in conjunction with a carry sequence, all of which are compatible with their respective masks, or states that there is no solution.
The operation of the fixed-point generator is discussed in the following sections.
Mask Combination Numbers and Case Numbers
The basic relations which control the construction of the sequences x m =i, y m =j, z m =k, (m=0, 1, . . . , N−1) and C m , (m=0, 1, . . . , N) are the condition of compatibility with the masks and Equation (16), previously discussed. Clearly these conditions might be self-contradictory. Where such contradictions exist, the fixed-point generator states that there is no solution.
Given an index m, each value of the bits i, j, k corresponds to a character in the appropriate mask. This character may be either an ‘x’ or a number (‘0’ or ‘1’). With such a classification of the characters of the mask, each triplet of masks elements is one of eight possible types of triplets (for example, all three of the characters may be ‘x’; i corresponds to a number and j and k both correspond to an ‘x’; and so forth). Each of the eight types of triplets may be assigned a number, which is denoted as MCN (Mask Combination Number). Table 2 below lists the values. In this table n means a number character in the mask (‘0’ or ‘1’) and x means an ‘x’ character in the mask.
TABLE 2
Mask Combination Numbers
MCN
0
1
2
3
4
5
6
7
i
n
n
n
n
x
x
x
x
j
n
n
x
x
n
n
x
x
k
n
x
n
x
n
x
n
x
Note that Equation (16) can be alternately expressed in the form:
i+j−k= 2 C m −C m+1 (21)
Given the masks M x , M y , M z and a numerical value for the index m, it is possible to assign an MCN value and the numerical values of some of the variables i, j, k. For MCN=0, 1, 2, 3, 4, 5, and 6, there is sufficient information to compute a Case Number CN, where
CN=i+j−k , when all three i, j, and k are known ( n )— MCN 0 (22)
CN=i+j , when only i and j are known ( n ) and k is unknown ( x )— MCN 1 (23)
CN=i−k , when only i and k are known ( n ) and j is unknown ( x )— MCN 2 (24)
CN=i, when only i is known (n) and k and j are unknown (x)—MCN 3 (25)
CN=i−k , when only j and k are known ( n ) and i is unknown ( x )— MCN 4 (26)
CN=j, when only j is known (n) and k and i are unknown (x)—MCN 5 (27)
CN=−k , when only k is known ( n ) and i and j are unknown ( x )— MCN 6 (28)
Then the pairs (C m ,C m+1 ) which are possible for each MCN, CN combination are as follows:
TABLE 3
(C m , C m+1 ) Pairs for MCN and CN values
MCN = 0, CN = i + j − k
CN = −1: (0, 1)
CN = 0: (0, 0), (1, 2)
CN = 1: (1, 1)
CN = 2: (1, 0), (2, 2)
MCN = 1, CN = i + j
CN = 0: (0, 0), (0, 1), (1, 2)
CN = 1: (0, 0), (1, 1), (1, 2)
CN = 2: (1, 0), (1, 1), (2, 2)
MCN = 2, CN = i − k or MCN = 4, CN = j − k
CN = −1: (0, 0), (0, 1), (1, 2)
CN = 0: (0, 0), (1, 1), (1, 2)
CN = 1: (1, 0), (1, 1), (2, 2)
MCN = 3, CN = i or MCN = 5, CN = j
CN = 0: (0, 0), (0, 1), (1, 1), (1, 2)
CN = 1: (0, 0), (1, 0), (1, 1), (1, 2), (2, 2)
MCN = 6, CN = −k
CN = −1: (0, 0), (0, 1), (1, 1), (1, 2)
CN = 0: (0, 0), (1, 0), (1, 1), (1, 2), (2, 2)
MCN = 7, CN=0
CN = 0: (0, 0), (1, 0), (0, 1), (1, 1), (1, 2), (2, 2)
The determination of the (C m ,C m+1 ) pairs in Table 3 is by straightforward application of Equation (21), given what is known about i, j, and k. For example, for MCN 0, all three are known, so the various combinations can be computed precisely. In the case i=j=0, k=1, CN=−1. According to Equation (21), the only values of C m ,C m+1 which can satisfy −1=2C m −C m+1 are C m =0 and C m+1 =1, so the only possible (C m ,C m+1 ) pair is (0,1), as shown in Table 3 for CN=−1 under MCN 0. As another example, for MCN 1 only i and j are known, and k is indeterminate and thus CN is simply given by i+j, as shown in Equation (23). For i=j=0, CN=0, and there are three (C m ,C m+1 ) pairs that give this result in Equation (21): (0,0) with k=0; (0,1) with k=1; and (1,2) with k=0. These are the values shown in Table 3 for CN=0 under MCN 1. The rest of Table 3 is compiled in the same manner. For MCN 7, a value of CN=0 is assigned, because all three of i, j, and k are indeterminate. For this value, the complete Set (20) is present.
This list of 15 CN values in Table 3 is exhaustive, because for each pair of MCN, CN all possible pairs (C m , C m+1 ) are included for all possible values. This list is a basis for the construction of feasible sequences C m , (m=0, 1, . . . , N). A feasible sequence C m is compatible with M C , where there exists at least one triplet of corresponding numbers x, y, z, compatible with M x , M y , M z , respectively. Since the list in Table 3 is exhaustive, it is possible to construct every feasible sequence C m , and these sequences are used to search for solving triplets x, y, z, such that no valid solution is excluded from being found.
List of n-Values
Recalling Restrictions (17), (18), and (19), it is seen that if, for some index mε{0, . . . , N−1}, C m =2 then it is necessary that C m+1 =2 also. And if C m+1 =2, then it is necessary that C m ≠0 (that is, C m ε{1, 2}). This implies that one of the following is true:
1. There exists a boundary index nε{1, . . . , N} such that C m =2 for all m≧n, C m =1 for m=n−1 and C m ε{0, 1} for all m<n. 2. All of the carries are 2 (n=0 in this case). 3. All of the carries are in {0, 1} (n=N+1 in this case).
A feasible boundary index nε{0, 1, . . . , N+1} is generally not unique, and there might exist several possible values for n. Therefore, construct a list of boundary index n-values which includes all of the values of n that correspond to solutions, and no other values of n. Clearly, for all n≦m<N, C m =C m+1 =2. So, looking in Table 3 it is seen that for all such m the pair (MCN,CN) must be one of: (0,2), (1,2), (2,1), (3,1), (4,1), (5,1), (6,0), (7,0). Since C n−1 =1, C n =2 for nε{1, . . . , N} it is inferred for such n that it is necessary for m=n−1 that the pair (MCN,CN) is one of: (0,0), (1,≠2), (2,≠1), (3,x), (4,≠1), (5,x), (6,x), (7,x), where ≠1 means CN≠1, ≠2 means CN≠2 and x means that CN may have any value. Additional restrictions on n are imposed by the mask M C . It is necessary that C n−1 , C n , . . . , C N are all compatible with this mask.
Given the masks, this permits the construction of a preliminary list of possible values of n. As seen below, this list is often too large, and some terms must be erased.
Feasible Carry Sequence
The sequence C m is completed, given a value for n, by setting values to C 0 , C 1 , . . . , C n−2 . These missing values of carries must all be in {0,1}. Hence, starting from Table 3 the list of pairs (C m ,C m+1 ) is modified by erasing from it all of the pairs which include 2. The remaining list, which is relevant to the construction of the missing carries, may be replaced by the following equivalent list of inference rules:
TABLE 4
Carry Sequence Inference Rules
MCN = 0, CN = i + j − k
CN = −1: C m = 0,C m+1 = 1
CN = 0: C m = C m+1 = 0
CN = 1: C m = C m+1 = 1
CN = 2: C m = 1, C m+1 = 0
MCN = 1, CN = i + j
CN = 0: C m = 0
CN = 1: C m = C m+1
CN = 2: C m = 1
MCN = 2, CN = i − k or MCN = 4, CN = j − k
CN = −1: C m = 0
CN = 0: C m = C m+1
CN = 1: C m = 1
MCN = 3, CN = i or MCN = 5, CN = j
CN = 0: C m = 1 C m+1 = 1
C m+1 = 0 C m = 0
CN = 1: C m = 0 C m+1 = 0
C m+1 = 1 C m = 1
MCN = 6, CN = −k
CN=−1: C m = 1 C m+1 = 1
C m+1 = 0 C m = 0
CN= 0: C m = 0 C m+1 = 0
C m+1 = 1 C m = 1
MCN = 7, CN = 0
CN = 0: No restrictions
Like the list of pairs in Table 3 from which Table 4 is derived, this set of inference rules is exhaustive in the sense that each feasible sequence C 0 , . . . , C n−1 , of {0,1} terms, must be compatible with these rules, and each such sequence, which is compatible with these rules and with M C , is feasible.
In setting values to the carries C 0 , . . . , C n−1 , these values are constrained by the mask M C and by the inference rules of Table 4. In addition, C n−1 =1 if nε{1, 2, . . . , N}. The mask M C uniquely defines those terms of C m which correspond to non ‘x’-characters (note, however, that a ‘2’ character in M C is permitted only for m≧n. Otherwise n should be erased from the list of n-values). The set of inference rules of Table 4 may be divided into three (not disjoint) groups:
1. Assignment rules: for example, C m =C m+1 =0; C m =1; etc. 2. Right continuation rules: for example, C m =1 C m+1 =1; C m =C m+1 ; etc. 3. Left continuation rules: for example, C m+1 =0 C m =0; C m =C m+1 ; etc.
In principle, the solution-seeking method illustrated in FIG. 4 is used here also, where input list 401 contains a list of prospective n-values and block 411 operates as described below to search for a suitable carry sequence or output that there is no solution.
First applying only the assignment rules, it is possible to assign values to some of the carry terms. Note that there are several ways to deduce a definite value for a C m (mask, assignment rules, C n−1 =1). It may happen that there may be contradictions. Therefore, each time a definite value is deduced for a given C m , it is necessary to check to see if the particular carry bit was assigned a different value earlier. A contradiction means that this particular n should be erased from the list of n-values.
Suppose all of the methods, described above for deducing a definite value for a C m , were used and no contradiction was found. Some of the defined carries may be neighbors (C m ,C m+1 ). For each such pair of neighbors it is necessary to find the MCN and CN corresponding to the index m, and test for a contradiction by the corresponding inference rule from Table 4. If there is a contradiction, that n must be erased from the list of n-values. If all of the pairs of neighbors were tested and no contradiction was found, the continuation rules are applied, one at a time. This process will create chains of consecutive defined carries, separated by chains of consecutive (yet) undefined carries. As the process continues the chains of undefined carries shrink and it may happen that one of them disappears completely. That is, the right end of one chain of defined carries becomes a neighbor of the left end of the following chain of defined carries. Such neighbors must be tested for contradiction by the inference rules of Table 4. If any contradiction is found then that n should be erased from the list of n-values. If the process ends and cannot be continued any further and no contradiction was found, then either all of the carries are defined and there is a complete, feasible, sequence of carries, or some chains of undefined carries were left over. In this case, a point was reached where no more contradictions are expected. It is then possible to choose one end of an undefined carries chain and choose for a value for that end of either 0 or 1, at random. No contradiction can arise from this operations because, as was mentioned above, the set of inference rules of Table 4 is exhaustive. The new carry becomes a left or a right end of a chain of defined carries. The continuation rules are applied to this new end, again and again, until the end of the chain meets an end of another chain or until no further continuation rule can be applied, and then an undefined carry is assigned at random. This process is repeated until all of the carries are assigned definite values. Note that if the new end meets another chain of defined carries, namely if the new end becomes a neighbor of another end there cannot arise a contradiction because the other end could not be continued at an earlier stage and this means that its new neighbor may have the value 1 or the value 0 without causing any contradiction.
As was mentioned above, if any contradiction was found then the value of n must be erased from the list of n-values. If there are contradictions for all values of n, that is, if at the end, the list of n-values is empty then the fixed point generator must state that there exists no solution and stop.
Through this process it is possible to discover if no feasible sequence of carries exists, and otherwise to produce, in principle, every feasible sequence of carries. If there is a feasible sequence of carries it can be used to construct every triplet of solving numbers x, y, z, as described below.
Number Construction from a Carry Sequence
Note that at this point, all contradictions in the carry sequence have been eliminated.
To construct the numbers x, y, and z, given a feasible carry sequence C m , first assume that this entire carry sequence is known and that it is feasible. For each value of mε{0, 1, . . . , N−1} there exist numerical values for C m , C m+1 , MCN, CN and perhaps some of the values i, j, k.
Next, start with Equation (21) i+j−k=2C m −C m+1 and transfer to the right hand side of this equation all of the known values for i, j, k. This results in an equation of form
α=RHS (29)
where the right hand side (RHS) has a known numerical value that equals a simple additive and/or subtractive combination (α□ of the unknown values of i, j, k.
It is easy to see that
RHS= 2 C m −C m+1 −CN (30)
and that α depends on MCN such that
α+ CN=i+j−k (31)
For instance, if MCN=3 then CN=i, α=j−k and Equation (29) becomes j−k=RHS. If MCN=2 then CN=i−k, α=j and Equation (29) becomes j=RHS, and so on. The form of Equation (29) and all of its solutions, in all of the possible cases, are summarized as follows:
TABLE 5
Values for i, j, and k
MCN = 0, α is an empty expression
RHS = 0: i, j, k are all known
MCN = 1, α = −k
RHS = −1 or 0: k = −RHS
MCN = 2, α = j
RHS = 0 or 1: j = RHS
MCN = 3, α = j − k
RHS = −1: (j, k) = (0, 1)
RHS = 0: (j, k) = (0, 0), (1, 1)
RHS = 1: (j, k) = (1, 0)
MCN = 4, α = i
RHS = 0 or 1: i = RHS
MCN = 5, α = i − k
RHS = −1: (i, k) = (0, 1)
RHS = 0: (i, k) = (0, 0), (1, 1)
RHS = 1: (i, k) = (1, 0)
MCN = 6, α = i + j
RHS = 0: (i, j) = (0, 0)
RHS = 1: (i, j) = (0, 1), (1, 0)
RHS = 2: (i, j) = (1, 1)
MCN = 7, α = i + j − k
RHS = −1: (i, j, k) = (0, 0, 1)
RHS = 0: (i, j, k) = (0, 0, 0), (0, 1, 1), (1, 0, 1)
RHS = 1: (i, j, k) = (0, 1, 0), (1, 0, 0), (1, 1, 1)
RHS = 2: (i, j, k) = (1, 1, 0)
Thus, knowing the numerical values of MCN and RHS for every mε{0, 1, . . . , N−1}, it is possible to select from Table 5 a solution which completes the triplet i, j, k, for every m. Wherever the list includes several solutions for some combination of MCN, RHS, one of the solutions is chosen at random. Making such choices for all values mε{0, 1, . . . , N−1} completes the construction of x, y, z.
Fixed-Point Generator Solution-Seeker
Based on the above discussion, the solution-seeking method illustrated in FIG. 4 can be used for the fixed point generator. First, list 401 is a list of possible n-values. Block 411 then operates as follows: In accordance with the procedures detailed above, try to construct the missing terms of C m . If there are any contradictions, there is no solution for the selected n, and decision-point 413 branches to erase block 417 . If there are no contradictions, then sequence C m is a feasible solution. Using the constructed sequence C m and masks M x , M y , M z , set values for i, j, and k for each mε{0, 1, . . . , N−1}. Whenever there is more than one possibility for choosing i, j, k, make a random choice. The found solution is the completed construction with x, y, z, and C m , and decision-point 413 branches to output block 415 to return the solution.
Operation of the Addition Significand Generator
Addition significand generator 235 ( FIG. 2 ) always applies fixed point generator 245 with N=p. The reasoning is as follows: the exponent of a + b is almost always equal to the exponent of c . The only exception to this is in the post-normalization case which occurs when a + b rounds upward to produce S c =1.00 . . . 0 exactly. In this case, the exponent of c is 1 greater than that of a + b . Temporarily ignoring this exceptional case (which is discussed below), align the significands S a , S b , and S c according to the values of Q a and Q b . When this is done, some of the trailing bits of S a , S b are positioned to the right of the least significant bit of S c and form “tails”, as shown below, which contribute to the sum c only through carry and/or rounding into the least significant bit of the sum:
With reference to FIG. 3 , input 303 to fixed point generator 245 contains the shifted and truncated masks of S a , S b as shown above. In addition, input 305 is a carries mask M C =“0xx . . . xC p ”, where C p ε{0, 1, 2} has the contribution of the tails, which combines the effects of carry and of rounding.
First, a numerical value is chosen for C p of 0, 1, or 2. Next, the tails are generated, and finally S c and the left parts of S a and S b are generated. This is done by using the fixed point generator, as detailed below.
Denote the leftmost bits of the tails by a 2 , b 2 , respectively, and the remainders of the tails by a 3 , b 3 :
Clearly, the value of C p is determined by a 2 , b 2 , a 3 , and b 3 .
Either Q a ε{0, 1} or Q b ε{0, 1}, and therefore either a 3 =0 or b 3 =0. So, denoting c 3 =a 3 +b 3 it is then clear that c 3 =a 3 if Q b ε{0, 1} and c 3 =b 3 if Q a ε{0, 1}. C p thus depends on a 2 , b 2 , and c 3 .
The Tails Triplet
Actually it is not necessary to know the whole sequence of the bits of c 3 , but only the result of an OR operation over all of the bits of c 3 , denoted herein as OR(c 3 ). The triplet of bits (a 2 , b 2 , OR(c 3 )) is herein denoted as the “tails triplet”. Thus, for instance, if the tails triplet is (1, 1, 0) and the rounding mode is round up then C p =1. If the tails triplet is (1, 0, 1) and the rounding mode is round to nearest/even then C p =1, and so on.
All of the possible tails triplets, for each of the rounding modes and for each of the possible values of C p , are as follows:
TABLE 6
Tails Triplets
round down
C p = 0: (0, 0, 0), (0, 0, 1), (0, 1, 0), (0, 1, 1), (1, 0, 0), (1, 0, 1)
C p = 1: (1, 1, 0), (1, 1, 1)
round up
C p = 0: (0, 0, 0)
C p = 1: (0, 0, 1) 0 , (0, 1, 0) 0 , (0, 1, 1) 1 , (1, 0, 0) 0 , (1, 0, 1) 1 , (1, 1, 0)
C p = 2: (1, 1, 1) 0
round to nearest/even
C p = 0: (0, 0, 0), (0, 0, 1), (0, 1, 0) 0 , (1, 0, 0) 0
C p = 1: (0, 1, 0) 0 0 , (0, 1, 1) 2 , (1, 0, 0) 0 0 , (1, 0, 1) 2 , (1, 1, 0), (1, 1, 1)
Some of the triplets listed in Table 6 have a numerical subscript and/or superscript: The subscript 0 means that the corresponding triplet implies round to even case. Such a case is possible with the indicated C p value only if the last character of S c is forced to be ‘0’. The existence of a superscript indicates that the rounding component of the contribution of the tails is 1, which means that a result with S c =1.00 . . . 0 is post-normalized and is potentially wrong, because the exponent may have changed size, thereby invalidating the original shifting assumption by 1 bit (as further discussed below).
The generation of S a , S b , S c starts by constructing a three-character mask for the tails triplet. The elements of this mask, which correspond to a 2 and b 2 are simply copied from M Sa , M Sb or are set to be ‘0’ if a 2 and/or b 2 fall outside of the range of the corresponding shifted mask. The element which corresponds to c 3 is set to be ‘1’ if the corresponding part of M Sa or M Sb includes at least one ‘1’ character. If not, the element will be ‘0’ if no ‘x’ exists in the appropriate part of M Sa or M Sb and ‘x’ otherwise.
After the mask of the tails triplet is ready, one tails triplet compatible with this mask is chosen from the complete list in Table 6. Note that in the case of round to nearest/even each of the triplets (0, 1, 0), (1, 0, 0) appears twice: once with C p =0 and once with C p =1. These appearances are considered to be distinct. Namely, a choice such as (0, 1, 0) with C p =0 is different from the choice (0, 1, 0) with C p =1.
Now that a tails triplet has been chosen, the construction of the two tails is straightforward. The construction of S c and of the left hand parts of S a , S b is performed by the fixed-point generator.
Exceptional Case
As previously mentioned, there is an exceptional case where the exponent of a+b is smaller by 1 than that of c.
If the tails triplet chosen from Table 6 does not have any superscript it means that even if the generated S c is 1.00 . . . 0, there is no post-normalization. In this case, the result is correct and acceptable.
If, however, the tails triplet has a superscript and the fixed-point generator produces S c =1.00 . . . 0 then it means that some thing may be wrong with the result and it is not certain that the produced S a , S b , and S c satisfy S c =round(2 −Qa S a +2 −Qb S b ), as it should. This is discussed here in further detail.
If the superscript is 0 then the result is definitely wrong and cannot be corrected. In such a case, the result should be discarded and the significands construction should be repeated.
If the superscript is 1 , it means that the result is in fact correct, and should be accepted.
If the superscript is 2 , it means that the c 3 part of the tails should be constructed with care: Note that there are only two tails triplets with a superscript 2 , in the list: They are (0, 1, 1) and (1, 0, 1) in the round to nearest/even mode, with C p =1. Since the resulting S c was 1.00 . . . 0 it means that the p+1 first bits of the exact sum were 011 . . . 1 and that c 3 should be concatenated to the right of this, in order to produce the complete exact sum. This means that in order for the result generated by the fixed point generator to be usable, the leftmost bit of c 3 should be 1. The rest of the bits of c 3 are not important. If the leftmost bit of c 3 cannot be chosen to be 1 because of mask constraints, it means that the solution should be discarded and significand construction should be repeated.
Note that no possible solution of the significands generator problem is excluded by the method of generation described above, not even those with S c =1.00 . . . 0 and exact sum 011 . . . 1c 3 .
Solution-Seeking Procedure for the Addition Significand Generator
To use the solution-seeker illustrated in FIG. 4 , it is first necessary to construct list 401 , and this is done by using Q a , Q b and M Sa , M Sb , to produce a three-character mask for the tails triplet, and then constructing a sublist of tails triplets compatible with this mask from the complete list in Table 6. List 401 contains these tails triplets. Block 411 operates by invoking the fixed-point generator to construct S c and the left hand parts of S a , S b . If the fixed-point generator states that there is no solution, then decision-point 413 branches to erase block 417 . Otherwise, use the chosen tails triplet to construct the tails, and thereby complete the construction of S a and S b , after which decision-point 413 branches to output block 415 , which outputs S c and the zero-padded left hand parts of S a , S b as the found solution.
Operation of the Subtraction Significand Generator
Denote c= a − b , and c =round(c). The rounding error is denoted by ε=| c −c|. If c is rounded down, c +ε= a − b , or b +( c +ε)= a . If c is rounded up, then c −ε= a − b , or b + c =( a +ε). In either case there is an exact identity which includes only one addition of nonnegative numbers. The numbers can be considered to be fixed-point numbers, and if there were masks for these three fixed-point numbers, it would be possible to use the fixed-point generator to generate them. This is in fact the case, as is shown as follows:
Note that the non-zero bits of ε always lie to the right of the least significant bit of c . Also, a ≧c a ≧ c , so the non-zero bits of ε lie to the right of the least significant bit of a as well. This means that the bits of c +ε are composed of the bits of c and the bits of ε written in sequence, one after the other. A similar point holds for a +ε. This can be illustrated graphically: Assume, for instance, that the rounding mode is round down, that Q b =3 and that Q c =1. Then the masks for a , b , and c +ε may be chosen to be
These masks are composed of the masks for S a , S b , S c , padding ‘0’ characters and padding ‘x’ characters. Note that, because ε can be anything, the mask for ε has ‘x’ characters; furthermore, because a is the largest of the three numbers a , b , and c , a determines the shift of the other two. Because the rounding mode for this example is round down, the rightmost three characters for the mask M a are all ‘0’. If the rounding mode were round up, the rightmost three characters for the mask M a would be ‘x’ instead.
The fixed-point generator is used to generate the three numbers and then extract from their binary representations the bits of S a , S b , S c . In this particular case for the fixed-point generator, N=p+3, and the mask for the sequence of carries is “0xx . . . xx0”. It turns out that the maximum needed value for N is of the order of 2p, because if Q b is larger than p it is necessary to know only if b >0, and the details of the bits of b are of no significance. A similar treatment may be used if the rounding mode is round up. In such a case, however, the bits of ε must be added to those of a instead of c .
Details for the Round Down Rounding Mode
The identity that must be used in the round down case is b +( c +ε)= a . In a similar manner to Table 1, the combinations of Q b , Q c which should be considered are listed below in Table 7.
TABLE 7
Q b , Q c Pairs for Subtraction
Q b
0
0
1
1
0
0
. . .
0
0
1
1
. . .
1
Q c
0
1
0
1
2
3
. . .
p−1
≧p
2
3
. . .
p
Q b
1
2
3
. . .
p−1
≧p
2
3
. . .
p
>p
Q c
>p
0
0
. . .
0
0
1
1
. . .
1
1
The common length of the masks that must be presented to the fixed-point generator for most of the combinations is N=p+max(Q b ,Q c ). The mask for S b should be padded to the left by Q b ‘0’ characters (if Q b >0) and to the right by Q c −Q b ‘0’ characters (if Q b <Q c ). The mask for S c should be padded to the left by Q c ‘0’ characters (if Q c >0) and by Q b −Q c ‘x’ characters to the right (if Q c <Q b ). The mask for S a never has to be padded to the left (because a ≧ b , a ≧ c ) and should be padded to the right by max(Q b ,Q c ) ‘0’ characters (unless Q b =Q c =0). The mask of the carries must always be of the form “0xx . . . xx0”.
The cases (Q b ,Q c )ε{(0,≧p), (1,>p), (≧p,0), (>p,1)} should be treated in a slightly different way:
In the two cases where Q c ≧p or Q c >p, S c =0, unless this is not compatible with its mask, in which case there is no solution. Generating a solution, then, is straightforward.
In the two cases where Q b ≧p or Q b >p, S b may be any bit string which is compatible with its mask. The three-number masks that must be presented to the fixed-point generator are of length N=p+Q c +1 each, where the mask for b is composed only of ‘0’ characters except for the rightmost one, which is ‘1’ if ≠0 and is ‘0’ otherwise. The mask for S c is padded by Q c ‘0’ characters to the left and by a single ‘x’ to the right. The mask for S a is padded by Q c +1 ‘0’ characters to the right. After a solution to the fixed-point problem is determined, the bit strings for S a , S b , and S c may be easily constructed.
Details for the Round Up Rounding Mode
The identity that must be used in the round up case is b + c =( a +ε). The combinations of Q b , Q c which should be considered are also those listed in Table 7. Again, in most cases, the length of the masks, presented to the fixed-point generator is N=p+max(Q b ,Q c ). The mask for S b is padded by Q b ‘0’ characters to the left (if Q b >0) and by Q c −Q b ‘0’ characters to the right (if Q b <Q c ). The mask for S c should be padded by Q c ‘0’ characters to the left (if Q c >0) and by Q b −Q c ‘0’ characters to the right (if Q c <Q b ). The mask for S a does not have to be padded on the left side. On the right side the mask for S a must be padded with Q c ‘0’ characters (if Q c >0) and by Q b −Q c ‘x’ characters on the right (if Q c <Q b ). The mask for the carries is, again, of the form “0xx . . . xx0”.
In the four cases where either Q c ≧p or Q b ≧p the treatment is, again, slightly different:
In the two cases where Q c ≧p, S c must be zero, unless this is not compatible with the mask, in which case there exists no solution.
In the two cases where Q b ≧p, ε= b and c = a (Q c =1 is impossible, then). So S b may be chosen to be any number which is compatible with its mask and S c =S a may be chosen to be any positive number which is compatible with the masks of both S a and of S c .
In the discussion above, it has been implicitly assumed that the exponents of c and of c are the same. This is always so in the case of round down. However, if round( ) is round up there exists one exceptional case: If the significand of c is 1.00 . . . 0 and ε>0 then this implicit assumption is not satisfied. Unless the leftmost bit of ε (the bit which corresponds to the leftmost ‘x’ character in the right padding of S a ) is 0, this leads to an error. So solutions returned by the fixed-point generator in which S c =1.00 . . . 0 and the leftmost bit of ε is 1 should be rejected, and an additional attempt to produce a solution should be made.
Details for the Round to Nearest/Even Rounding Mode
For round to nearest/even the rounding is sometimes round up and sometimes round down. So the algorithm for this case is a mixture of the algorithms for round up and for round down. Consider again the combinations of Q b , Q c listed in Table 7. In the same way that the masks for S a , S b , S c were extended and padded for round down and round up, those masks are also extended and padded in the round to nearest/even case. A new factor, however, is the splitting of the discussion of each combination of Q b , Q c into four subcases:
1. Case of round to nearest/down, in which the identity b +( c +ε)= a is used, and the extended masks of S a , S b , S c are padded in the same way as in the round down case, except that the “xx . . . x” padding that corresponds to ε is replaced by “0xx . . . x” padding. 2. Case of round to nearest/up: The identity b + c =( a +ε) is used, and the extended masks of S a , S b , S c are padded in the same way as in the round up case, except that the “xx . . . x” padding, that corresponds to ε is replaced, again, by “0xx . . . x” padding. As in the round up case a solution with S c =1.00 . . . 0 is rejected, unless the leftmost x (of ε) is replaced in the solution by 0 (i.e. the bits of ε are compatible with “00xx . . . x”) or the bits of ε in the solution are 0100 . . . 0 exactly. 3. Case of round to even/down: This is exactly like case 1 above, except that the “0xx . . . x” padding is replaced by “100 . . . 0” padding and the last character of the mask of S c is replaced by ‘0’ (this can be done only if the original last character of M Sc is ‘0’ or ‘x’). 4. Case of round to even/up: This is exactly like case 2 above, except that the “0xx . . . x” padding is replaced by “100 . . . 0” padding and the last character of the mask of S c is replaced by a ‘0’ (again, this can be done only if the original last character of M Sc is ‘0’ or ‘x’). A solution with S c =1.00 . . . 0 must be rejected. Thus, a solution with S c =1.00 . . . 0 cannot be produced in this case. Note, however, that such a solution may be produced in case 2 (see the discussion at the end of case 2, where the bits of ε are 0100 . . . 0).
This discussion may be completed in a straightforward manner to also include the cases where Q b ≧p or Q c ≧p.
Solution-Seeking Procedure for the Subtraction Significand Generator
Subtraction significand generator 240 ( FIG. 2 ) does not utilize sets of “tails triplets” as are employed by addition significand generator 235 , and therefore does not recursively use the solution-seeker method illustrated in FIG. 4 . Instead, the solution-searching action of subtraction significand generator 240 is part of the floating-point subtraction test-generator's solution-seeking block 411 is as follows: Given numerical values for Q b , Q c from calculator 225 based on the particular values of q b , q c selected from the floating-point subtraction test-generator's list 401 , use Table 7 to classify this pair in order to use the appropriate procedure, out of those described above, to generate three significands. If the construction was successful decision-point 413 branches to output block 415 , which outputs the complete floating-point solution (biased exponent and significand). Otherwise, if the construction failed, decision-point 413 branches to erase block 417 which erases the selected q b , q c selected from the floating-point subtraction test-generator's list 401 .
The Biased Exponent Generators
Biased exponent generator 210 ( FIG. 2 ) includes both definite biased exponent generator 215 and indefinite biased exponent generator 220 . In both of these biased exponent generators q 1 ε{0, 1} and e 3 =e 1 +q 1 . There are then two possible cases: e 3 =e 1 and e 3 =e 1 +1. In the case of definite biased exponent generator 215 , there is a given definite value of q 2 such that e 3 =e 2 +q 2 =e 1 +q 1 . That is, the exponent of the output result is a definite amount different from the exponent of either input operand. In the case of indefinite biased exponent generator 220 , however, the value of q 2 is indefinite, and it is merely known that q 2 >q. That is, the exponent of the output result is not a definite amount different from the exponent of either input operand. The definite biased exponent generator and the indefinite biased exponent generator are non-limiting examples of a more general definite exponent generator and a more general indefinite exponent generator, respectively, that obtain solutions for exponent pairs in these two cases.
Definite Biased Exponent Generator
In the case e 3 =e 1 , the common value of e 1 and e 3 must be compatible with both the masks M 1 and M 3 . If the two masks have different number characters in the same position then they are incompatible and no pair e 1 , e 3 exists. Otherwise, it is very easy to produce their intersection, M 13 , based on the individual character intersections as shown in Table 8 below. Note that incompatible character intersections are not defined and are denoted by Ø.
TABLE 8
Mask Character Intersections
The problem is now one of producing e 2 and e 3 that satisfy e 3 =e 2 +q 2 . There are masks for e 2 , e 3 (i.e. M 2 , M 13 ) and it is possible to construct a mask composed of numerical characters only for q 2 . This is equivalent to a problem of fixed-point addition, and therefore, the problem may be solved by using the fixed-point generator.
In the case e 3 =e 1 +1, note that the right hand end of the string of bits of biased exponent e 1 , must be one of the following: 0, 01, 011, 0111, . . . , 011 . . . 1 (the last string is of length w). Because e 3 =e 1 +1, the right hand end of e 3 must be, respectively: 1, 10, 100, 1000, . . . , 100 . . . 0 (here also the last string is of length w). Comparing the possible right ends of e 1 , e 3 with the masks M 1 , M 3 it is usually possible to erase some of the possibilities and what is left is a reduced list of pairs of right-hand ends of e 1 , e 3 (which constitute solution-seeker list 401 in FIG. 4 ). In any of these pairs, the left ends of e 1 , e 3 must be identical. This means that the masks of e 1 and e 3 may be chosen to be composed of known numerical characters in the right ends, and of the intersection of the left hand ends of M 1 and M 3 (if the left ends of M 1 and M 3 are incompatible then the corresponding pair of right ends, will be erased from list 401 ).
Thus, every choice of a pair of right ends of e 1 , e 3 results in a condition similar to the one for the case e 1 =e 3 : There are masks M 2 , M 13 for e 2 , e 3 and a mask for q 2 , and e 2 , e 3 must be found from the relation e 3 =e 2 +q 2 . This, again, can be solved by the fixed-point generator. If the generator states that there is no solution it means that the selected pair of right ends will be erased from list 401 , and another pair should be selected and tried. If list 401 is empty it means that there is no solution which satisfies e 3 =e 2 +1.
When employing the solution-seeker illustrated in FIG. 4 , given M 1 , M 3 , and q 2 as a selection, the procedure for block 411 is as follows:
1. If M 1 and M 3 are incompatible, output that there is no solution. Block 411 is complete, after which decision-point 413 branches to block 417 . Otherwise, if M 1 and M 3 are compatible, construct M 13 and continue. 2. If M 13 exists, present M 2 , M 13 , and q 2 to the fixed point generator to generate e 2 and e 3 satisfying e 3 =e 2 +q 2 . 3 If the fixed point generator states that there is no solution, output that there is no solution. Block 411 is complete, after which decision-point 413 branches to block 417 . Otherwise, if there exist e 2 and e 3 satisfying e 3 =e 2 +q 2 , construct e 1 from e 3 . 4. Return e 1 , e 2 , and e 3 . Block 411 is complete, after which decision-point 413 branches to block 415 to output the solution e 1 , e 2 , and e 3 .
Indefinite Biased Exponent Generator
The analysis of the indefinite biased exponent generator is similar to the above analysis of the definite biased exponent generator, up to the point where there exists a new mask, M 13 , for e 3 (this applies to the case e 3 =e 1 as well as to the case e 3 =e 1 +1). Thus, the remaining problem is to generate q 2 , e 2 , and e 3 where there are masks M 2 and M 13 for e 2 and e 3 , respectively, which satisfy the relation (e 3 −e 2 )=q 2 >q.
The smallest e 2 that is compatible with M 2 is obtained by replacing each ‘x’ in M 2 by ‘0’, and this is denoted by e 2 SMALLEST . The largest e 3 which is compatible with M 13 is obtained by replacing each ‘x’ in M 13 by a ‘1’, and this is denoted by e 3 LARGEST . There exists a solution for the indefinite biased exponent generator if and only if e 3 LARGEST −e 2 SMALLEST >q. If this inequality is not satisfied, the indefinite biased exponent generator reports that no solution exists, and is finished.
If a solution exists, it is necessary to choose a random pair e 2 ′, e 3 ′ for which e 3 ′−e 2 ′>q, and for which e 2 ′ and e 3 ′ are compatible with M 2 and M 13 , respectively. This is done as described below:
To start, erase from M 2 all of the ‘0’ and ‘1’ characters, to leave a submask composed of ‘x’ characters only. The numbers e 2 o which are compatible with this submask, are in a natural isomorphic (one-to-one) correspondence with the numbers e 2 that are compatible with M 2 . Clearly, e 2 is a monotonically-increasing function of e 2 o and vice versa. Similar relations exist between e 3 and e 3 o via the mask M 13 .
The construction of random e 2 ′ and e 3 ′ which are compatible with the masks M 2 and M 13 , respectively, and satisfy e 3 ′−e 2 ′>q, is illustrated graphically in FIG. 5 and is computed analytically as follows (in this description, e 2 o , e 2 o SMALLEST , e 2 o LARGEST , e 2 o ′ correspond to e 2 , e 2 SMALLEST , e 2 LARGEST , e 2 ′, respectively, by the isomorphic correspondence via M 2 ; and e 3 o , e 3 o LARGEST , e 3 o ′, e 3 o ′ SMALLEST correspond to e 3 , e 3 LARGEST , e 3 ′, e 3 ′ SMALLEST , respectively, via M 13 ). FIG. 5 shows an e 2 axis 501 and an e 3 axis 503 .
1. Compute e 2 SMALLEST , e 3 LARGEST with e 2 o SMALLEST =00 . . . 0, and e 3 o LARGEST =11 . . . 1, respectively. A horizontal e 2 SMALLEST line 505 and a vertical e 3 LARGEST line 507 thus delineate two boundary lines of the solution space, which intersect at a point 509 . For convenience, also compute e 2 MAXIMAL , e 3 MINIMAL with e 2 o MAXIMAL =11 . . . 1, and e 3 o MINIMAL =00 . . . 0, respectively. A horizontal e 2 MAXIMAL line 506 and a vertical e 3 MINIMAL line 508 , and a point 510 at the intersection of line 506 and line 507 are useful in performing searches, as will be discussed below. 2. Compute e 2 o LARGEST =max{e 2 o |e 3 LARGEST −e 2 >q}. This may be done by any convenient search-and-test method, but it is well-known in the art that a convenient and rapidly-converging search method for monotonic functions is the binary, or “bisection” search, where an interval having 2δ elements is divided into two contiguous intervals of δ elements each, whose boundary point can be quickly evaluated to determine in which of the two intervals the next iteration of the search should be performed (where an interval has an odd number of elements, 2δ+1, the “bisection” breaks the interval into intervals of δ and δ+1 elements, respectively). Graphically, this is represented on the line segment defined by point 509 and point 510 , which may be successively bisected until e 2 LARGEST is found. Also graphically, an e 2 LARGEST point 511 establishes an upper limit on the extent of the solution space. A line 513 represents e 3 −e 2 =q 2 where q 2 is the minimum value such that q 2 >q. Line 505 , line 507 , and line 513 and the area enclosed thereby, thus define a solution space 514 , where e 3 −e 2 >q. Note that it is not necessary to determine line 513 or the analytical counterpart thereof, nor is it necessary to determine all the solutions in solution space 514 . It is only necessary to determine a single point at random within space 514 , such that every point within space 514 has approximately the same non-zero probability of being selected. 3. Choose an integer e 2 o ′ε[e 2 o SMALLEST , e 2 o LARGEST ], at random, and from this derive e 2 ′. Graphically, e 2 ′ is represented by a horizontal line 518 through a point 515 , which is chosen randomly in the line segment defined by point 509 and point 511 , inclusive of point 509 and point 511 . 4. Compute e 3 o ′ SMALLEST =min{e 3 o |e 3 −e 2 ′>q}, and from this derive e 3 ′ SMALLEST . This can be done, for example, using a binary search, which is graphically represented on the line segment defined by point 515 and a point 516 , which is defined by the intersection of line 508 and line 518 . A point 517 represents e 3 ′ SMALLEST , and it can be seen that point 517 necessarily lies on line 513 . 5. Choose an integer e 3 o ′ε[e 3 o ′ SMALLEST , e 3 o LARGEST ] at random, and from this derive e 3 ′. Graphically, a point 519 chosen randomly on the line segment between point 515 and point 517 will have coordinates e 2 ′, e 3 ′, which is guaranteed to be in solution space 514 .
Alternatively, it is possible to solve for e 2 o ′ and e 3 o ′, and afterward derive e 2 ′ and e 3 ′. Set the returned solution e 2 =e 2 ′ and e 3 =e 3 ′. The right end of e 1 is known and the left end may be copied from e 3 . Also, q 2 =e 3 ′−e 2 ′.
When employing the solution-seeker illustrated in FIG. 4 , given M 1 and M 3 as a selection, the procedure for block 411 is as follows:
1. If M 1 and M 3 are incompatible, output that there is no solution. Block 411 is complete, after which decision-point 413 branches to block 417 . Otherwise, if M 1 and M 3 are compatible, construct M 13 and continue. 2. Using the above procedure, produce random e 2 ′ and e 3 ′ which are compatible with M 2 and M 13 , respectively, and which satisfy e 3 ′−e 2 ′>q. If such e 2 ′ and e 3 ′ do not exist, output that there is no solution. Block 411 is complete, after which decision-point 413 branches to block 417 . Otherwise, if e 2 ′ and e 3 ′ exist, continue. 3. Set e 2 =e 2 ′, e 3 =e 3 ′, and q 2 =e 3 ′−e 2 ′ and construct e 1 from e 3 . 4. Return e 1 , e 2 , e 3 , and q 2 . Block 411 is complete, after which decision-point 413 branches to block 415 to output the solution e 1 , e 2 , e 3 , and q 2 .
While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made.
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A method and system for generating numerical test cases for testing binary floating-point arithmetic units for addition and subtraction operations, in order to verify the proper operation of the units according to a specified standard. The space for eligible test-cases is compatible with masks which stipulate the allowable forms of the operands and the result, including constant as well as variable digits in both the exponent and significand fields. The test-cases, which are generated randomly, cover the entire solution space without excluding any eligible solutions. All standard rounding modes are supported, and if a valid solution does not exist for a given set of masks, this fact is reported. The method is general and can be applied to any standard, such as the IEEE floating-point standard, in any precision. A system according to the present invention utilizes a set of sub-generators for biased exponents and significands, and also incorporates a fixed-point generator for performing calculations common to the other generators. The method relies on searching for solutions based on feasible carry sequences, and is also capable of generating test-cases for mask-constrained carry sequences.
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TECHNICAL FIELD
This disclosure is related to catalyst materials for the selective oxidation of carbon monoxide in a flowing gas stream comprising carbon monoxide, ammonia, and oxygen. For example, such catalysts may be useful in the treatment of exhaust gas from a lean burn, gasoline-fueled engine that is operated to passively provide ammonia for the reduction of nitrogen oxides in the exhaust.
BACKGROUND
Gasoline engines on automotive vehicles have been controlled to operate close to a stoichiometric air-to-fuel ratio (AFR) so that carbon monoxide (CO), unburned or partially burned hydrocarbons (HC), and nitrogen oxides (NO X ) in the exhaust stream can simultaneously be converted to carbon dioxide (CO 2 ), nitrogen (N 2 ), and water when passed in contact with a suitable platinum group metal (PGM) catalyst. In this mode of engine operation, the catalyst is characterized as a three-way-catalyst (TWC). With an ever increasing need for higher fuel economy there is current interest in operating gasoline engines, such as spark-ignition direct-injection (SIDI) engines, at AFR values that are relatively lean of the stoichiometric ratio (i.e., fuel-lean). The direct injection of gasoline into each engine cylinder allows a combustible air-fuel mixture to be formed near the spark plug for initiating combustion with leaner mixtures elsewhere in the combustion chamber. In some limited periods of engine operation, the AFR may be slightly rich of the stoichiometric ratio, but for most periods of engine operation the engine is operated fuel-lean to maximize fuel efficiency.
In comparison to stoichiometric AFR engine operation, fuel-lean engine operation reduces the amount of CO and HC in the exhaust, but increases the amount of NO X , which must be removed. The exhaust from such lean burn engines is still passed through a PGM catalyst-containing flow-through reactor to oxidize much of the CO and HC to CO 2 and water. But then a reductant material is added to the exhaust stream that is reactive with NO X to convert it to N 2 and water. The reductant material-containing exhaust is further passed through a reduction catalyst-containing flow-through reactor to promote the reduction of NO X to N 2 and water. Since the added reductant material and the reduction catalyst must work together in treatment of the exhaust, this practice is called a selective catalytic reduction (SCR) with respect to the removal of NO X .
In a known SCR practice (especially for diesel engines), it is common to store an aqueous solution of urea on the vehicle and to inject a controlled amount of urea solution, as needed, into the exhaust stream. The urea quickly decomposes into ammonia (and carbon dioxide), and the ammonia serves as the reductant material for the NO X reduction reaction. The flowing stream is then passed over a suitable reduction catalyst, such as a particulate copper-exchanged zeolite and/or an iron exchanged zeolite material. This method of NO X reduction is commonly referred to as an NH 3 -selective catalytic reduction (SCR) of NO X .
The on-vehicle storage of a reductant material, such as urea, and its managed injection into the flowing exhaust from the engine permits flexibility in the management of lean-burn engine operation. The NO X content of the exhaust may be measured with a NO X sensor, and the addition of the reductant material may be computer-controlled in response to the output of the NO X sensor. But the vehicle operator must continually replenish the supply of urea solution, and must also keep the solution from freezing. Ammonia is a suitable reductant for NO X in a vehicle exhaust stream, but there would be a benefit if the reductant or its precursor did not have to be separately stored on the vehicle.
U.S. Patent Application Publication No. 2010/0107605 (the “'605 application”), titled “Passive Ammonia-Selective Catalytic Reduction for NO X Control in Internal Combustion Engines,” is assigned to the assignee of this invention and discloses a method of passively generating NH 3 in an exhaust stream of a multi-cylinder, spark ignition, direct fuel injection, four stroke, gasoline engine that is primarily operated in a fuel-lean mode. But there are periods during which the “lean-burn” engine operates close to a stoichiometric AFR, or slightly fuel-rich of the stoichiometric ratio. Such periods may include, for example, engine-idle modes and vehicle acceleration modes of operation. The inventors in the '605 application recognized that oxygen-depleted engine exhaust contained NO X , CO, and hydrogen in sufficient quantities and proportions to form ammonia as the exhaust flowed through the PGM flow-through reactor close-coupled to the exhaust manifold of the engine. The inventors further recognized and disclosed practices for utilization of this passively-generated ammonia to reduce NO X in a NH 3 -SCR catalyst-containing flow-through reactor located downstream of the PGM reactor in the flow of the exhaust. The inventors recognized that, rather than adding urea solution to the exhaust, the passively-generated ammonia may eliminate the need for urea storage and injection.
The downstream NH 3 -SCR catalyst serves to temporarily store the passively-generated NH 3 during fuel-rich operation. During subsequent periods of fuel-lean engine operation, the NH 3 -SCR catalyst effectively converts NO X in the exhaust stream to N 2 and water using the stored NH 3 . But, this passive NH 3 generation method requires the engine's modes of operation to be efficiently managed to provide enough NH 3 to the NH 3 -SCR catalyst during fuel-rich operation so that a suitable supply of NH 3 is available on the NH 3 -SCR catalyst during fuel-lean operation to remove NO X from the exhaust.
It is recognized that NH 3 generation on a PGM catalyst is enhanced when the AFR of the engine's combustible mixture is about 14 to 14.2 during fuel-rich operation. However, when the engine is operating in this fuel-rich range, the PGM catalyst may not then serve to effectively oxidize the CO in the exhaust due to the temporarily diminished supply of oxygen. And the CO is not likely to be oxidized in the NH 3 selective reduction reactor either.
One method of removing CO from the exhaust stream resulting from these fuel-rich periods includes passing the exhaust stream in contact with a second oxidation catalyst and with an auxiliary air injection, downstream of the PGM catalyst to promote the oxidation of residual CO in the exhaust to CO 2 and water. However, this oxidation catalyst must be able to oxidize the residual CO without also oxidizing the NH 3 which is to be used by the downstream reduction catalyst-containing flow-through reactor.
SUMMARY OF THE DISCLOSURE
This disclosure describes an oxidation catalyst that can be used to preferentially catalyze the oxidation of CO in a gas stream comprising at least carbon monoxide, ammonia, and oxygen. As will be described further, the oxidation catalyst is usually used in the form of small particles of mixed oxides of cerium, zirconium, and copper (CeZrCuO X ) coated on wall surfaces of a flow-through reactor. When the temperature of the gas stream is in a suitable range, the catalyst effectively oxidizes carbon monoxide to carbon dioxide with minimal effect on the ammonia content of the gas stream. While the disclosed catalyst is useful generally for selective treatment of a stream of CO and ammonia, it is particularly useful for selective oxidation of CO when ammonia is generated in a CO-containing fuel-rich engine exhaust then flowing over a PGM catalyst. In this important embodiment of the invention, carbon monoxide is converted to carbon dioxide, but the ammonia content of the exhaust stream is preserved for use in an NH 3 -SCR reactor for NO X . Accordingly, this oxidation catalyst may be referred to herein as a CO-selective oxidation catalyst.
In one embodiment, this CO-selective oxidation catalyst may be used in an exhaust treatment system for a lean-burn engine along with: (1) a PGM catalyst, preferably close-coupled to the exhaust manifold, and (2) at least one zeolite-based NH 3 -SCR catalyst, which is positioned in the exhaust flow downstream of the PGM catalyst. In this system, the CO-selective oxidation catalyst is located downstream of the PGM catalyst and upstream of at least one NH 3 -SCR catalyst reactors. In this arrangement, the CO-selective oxidation catalyst minimizes oxidation of the NH 3 generated by the PGM catalyst in the exhaust stream during fuel-rich engine operation. Thus, the NH 3 will be available to one or more NH 3 -SCR catalyst reactors to participate in NO X reduction reactions during fuel-lean operation.
In another embodiment, the exhaust treatment system may include an O 2 dosing or injection device, located upstream of the CO-selective oxidation catalyst to provide a suitable amount of oxygen in the exhaust stream for selective oxidation of CO over the mixed oxide catalyst. The O 2 dosing device should be placed downstream of the PGM catalyst so as not to interfere with the PGM catalyst's NH 3 -generation performance.
In accordance with disclosed embodiments, the particulate mixed oxide CeZrCuO X catalyst may be used to effectively and selectively catalyze the oxidation of CO in NH 3 and O 2 -containing exhaust streams which are at a temperature in the range of about 200-400° C. In this temperature range the mixed oxide particles have minimal tendency to oxidize ammonia.
The CeZrCuO X mixed oxide particles may be prepared for use as the CO-selective oxidation catalyst using a co-precipitation method. In some preferred embodiments, the molar ratios of Ce, Zr, and Cu in the CO-selective oxidation catalyst may be controlled to fall within the following ranges: Ce/(Ce—Zr—Cu)=0.50-0.70, Zr/(Ce—Zr—Cu)=0.10-0.20, and Cu/(Ce—Zr—Cu)=0.15-0.35, with the sum of the molar ratios of Ce, Zr, and Cu equal to 1. The value of x depends on the proportions and oxidation state of the metal elements but typically is in the range of about one to 2 + or three. These compositions may be formed by dissolving suitable precursor compounds of cerium, zirconium, and copper in desired molar proportions in a common solvent. Preferably the precursor compounds contain oxygen. For example, nitrates of cerium, zirconium, and copper may be dissolved in water.
In the example of an aqueous solution of the respective nitrates, a precipitating agent, such as ammonia or sodium hydroxide, may be added to increase the pH of the solution and trigger co-precipitation of Ce, Zr, and Cu mixed hydroxides. The dried precipitate may be calcined in air at a temperature of about 400° C. to 500° C. for 4 to 6 hours to dehydrate the Ce, Zr, and Cu hydroxides and form mixed oxides of the respective base metals. The term “mixed oxide” is used in this specification to mean oxides that may contain cations of more than one base metal element or that the cations may be present in more than one oxidation state.
In many embodiments of the invention the mixed oxide catalyst will be used in combination with other catalytic reactors to dynamically treat the exhaust constituents from a vehicle engine that operates primarily in a fuel-lean mode, but with intervening periods of fuel-rich mode operation. Indeed, the mixed oxide catalyst will be particularly useful when engine operation is managed to provide a passive supply of ammonia for the catalytic reduction of NO X produced in lean-burn engine operation. In general, the fuel-lean or fuel-rich engine exhaust is passed first through a PGM catalyst-containing reactor that is close-coupled to the engine exhaust manifold (for higher exhaust gas temperatures), and then through one or more downstream NH 3 -SCR reactors. Thus, the mixed oxide catalyst of this invention will typically be used immediately after the exhaust gas has passed through the PGM reactor.
The mixture of carbon monoxide and ammonia will be formed, as described above in this specification, when exhaust constituents from a vehicle's engine fuel-rich operation is passed in contact with a PGM catalyst. The PGM catalyst may include particles of one or more platinum group metals (PGMs), such as platinum (Pt), palladium (Pd), and rhodium (Rh), supported on particles of alumina (Al 2 O 3 ) and/or ceria (CeO 2 ). However, it may be preferred to use PGM materials that do not store oxygen during fuel-lean operation for oxidation during fuel-rich operation so as to minimize oxidation of ammonia. For example, the PGM catalyst may comprise Al 2 O 3 -supported particles of Pd and Rh, wherein the molar ratio of Pd to Rh is 6:1. The downstream NH 3 -SCR catalyst may comprise particles of a copper (Cu) or iron (Fe) ion-exchanged suitable zeolite or silicoaluminophosphate composition.
Particles of the PGM catalyst, the CeZrCuO X mixed oxide catalyst, and the NH 3 -SCR catalyst may be dispersed on one or more, high surface area, support bodies in the form of a thin washcoat layer or layers. These catalyst-bearing support bodies may be housed within flow-through reactors and positioned along the flow path of the exhaust stream from the engine. The specific location of each of these reactors in the exhaust treatment system may be dependent upon the operating temperature range of each of the catalyst materials. In general, particles of the PGM catalyst may be housed within a flow-through reactor that is close-coupled to the engine, and particles of the NH 3 -SCR catalyst may be housed downstream in the exhaust flow path in one or more flow-through reactors that are located under the vehicle floor. The CO-selective oxidation catalyst may be positioned in the exhaust system at locations downstream of the PGM reactor and suitable for oxidizing CO and preserving ammonia for an NH 3 -SCR reactor.
It is generally found that a vehicle engine can be managed to operate fuel rich during engine idling, vehicle acceleration, and other modes of operation even when the engine is managed to operate fuel-lean during most of its operating modes. So long as the NH 3 -SCR catalyst particles have an adequate supply of NH 3 , NO X may be continuously removed from the exhaust stream, even during prolonged periods of fuel-lean engine operation. To determine when such a fuel-rich period or cycle should be initiated, the exhaust system may include at least one NO X sensor located downstream of the one or more NH 3 -SCR reactors. If a NO X sensor indicates that NO X is escaping from the one or more NH 3 -SCR reactors, a fuel-rich engine operation cycle may be triggered to replenish NH 3 storages sites on the NH 3 -SCR catalyst particles. In addition, each NH 3 -SCR reactor may be equipped with a NH 3 sensor to signal when the NH 3 storages sites on the NH 3 -SCR catalyst are saturated with NH 3 so that fuel-lean operation can quickly resume.
Furthermore, the passive NH 3 -SCR system may replenish NH 3 storages sites on the NH 3 -SCR catalyst by taking advantage of the fuel-rich periods that inevitably and repeatedly occur during normal, every-day driving conditions.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustration of an automotive vehicle's internal combustion engine, fuel supply system, air intake system, and exhaust system. In this illustration, the exhaust system includes three serially-arranged catalyzed flow-through reactors which are formulated to cooperatively and successfully treat the exhaust stream from the engine before discharge to the atmosphere.
FIG. 2 is a cutaway view of one of the schematically illustrated catalyzed flow-through reactors depicted in FIG. 1 . This catalyzed flow-through reactor includes a suitable high temperature capability and oxidation resistant metal container, which houses a catalyst-bearing support body that is held in place by a mounting material. In this illustration, the support body is an extruded ceramic honeycomb-shaped monolith and includes several small, square, parallel flow-through channels which are defined by walls that extend longitudinally from an inlet to an outlet face of the support body. A portion of the container, the mounting material, and the support body have been cut-way in this illustration to better reveal the internal structure of the support body.
FIG. 2A is an enlarged view of a portion of the inlet face of the extruded ceramic honeycomb-shaped support body depicted in FIG. 2 , which better reveals the internal flow-through channels and walls of the support body.
FIG. 3 is a graph of Conversion (%) vs. Temperature (° C.) showing the CO (solid line curve) and NH 3 (dashed line curve) conversion performance of a conventional Pd/Rh three-way catalyst as a function of temperature in a gas stream comprising 5000 ppmv CO, 1500 ppmv NH 3 , 5 vol. % CO 2 , 0.5 vol. % O 2 , 5 vol. % H 2 O, with N 2 as balance; SV=30,000 h −1 . The percent CO and NH 3 conversion values were calculated by comparing the concentration of CO and NH 3 in the gas stream at both the inlet ([CO] inlet or [NH 3 ] inlet ) and the outlet ([CO] outlet or [NH 3 ] outlet ) of a quartz tubular reactor.
FIG. 4 is a graph of Conversion (%) vs. Temperature (° C.) showing the CO (solid line curve) and NH 3 (dashed line curve) conversion performance of a Ce 0.6 Zr 0.15 Cu 0.25 O 2 catalyst as a function of temperature in a gas stream comprising 5000 ppmv CO, 1500 ppmv NH 3 , 5 vol. % CO 2 , 0.5 vol. % O 2 , 5 vol. % H 2 O, with N 2 as balance; SV=30,000 h −1 . The percent CO and NH 3 conversion values were calculated by comparing the concentration of CO and NH 3 in the gas stream at both the inlet ([CO] inlet or [NH 3 ] inlet ) and the outlet ([CO] outlet or [NH 3 ] outlet ) of a quartz tubular reactor. The region between darkened vertical lines at 200° C. and 400° C., also indicated by the horizontal line with arrow heads, represents the temperature range at which the CeZrCuO X catalyst can be effectively used to selectively oxidize CO, instead of NH 3 in exhaust streams.
DETAILED DESCRIPTION
FIG. 1 is a schematic illustration of the engine and exhaust passage system of an automotive vehicle 10 that includes an internal combustion engine 12 , a fuel supply system 14 , an air intake system 16 , and an exhaust system 18 . In modern engines, the operation and coordination of each of these systems is electronic computer-controlled as part of an overall engine management system. The multi-cylinder, reciprocating piston, internal combustion engine 12 may be a compression ignition engine (i.e., diesel engine), a spark ignition engine (i.e., gasoline engine), or a combination. During its operation, engine 12 inducts or draws in air flow 20 by the air intake system 16 , which includes an air filter 22 , a throttle-body valve 24 , and an intake manifold 26 coupled to the engine 12 . The engine 12 is supplied with fuel by the fuel supply system 14 , which includes a fuel tank 28 , a fuel pump 30 , and a fuel filter 32 that deliver fuel through a fuel line to the intake manifold region 34 of the engine overlying the cylinders 36 of the engine.
In FIG. 1 , the intake manifold region 34 is the area of the engine in which a plurality of fuel injectors or nozzles (not illustrated) may be located. The fuel injectors or nozzles of the fuel injection system are configured and controlled to open for an amount of time to dispense or spray a desired amount of pressurized fuel near intake valve openings (not illustrated) or directly into combustion chambers of the engine's cylinders 36 . Alternatively, the fuel injection system may include a single fuel injector that is located at a suitable position within the intake manifold region 34 . This single injector may be controlled to dispense a predetermined amount of fuel into the incoming air flow 20 so that the desired amount of fuel is sequentially supplied to each of the cylinders 36 of the engine 12 as their respective intake valves open to receive the carefully controlled charge of air and fuel.
The management of airflow and fuel injection and amount and timing to the engine in response to driver throttle or brake actuation is provided by at least one electronic control module (ECM) 38 . The ECM 38 monitors certain engine operating parameters by receiving input data through a plurality of signal leads which are attached to various sensors on the engine and the engine's related systems (not shown). The ECM 38 processes the input data and generates output data which is sent via another set of signal leads to actuators on various engine and vehicle components. In FIG. 1 , no leads are shown from any engine systems to the ECM 38 and no leads are shown to any actuators on the engine or on vehicle components. However, a plurality of leads would normally be present as part of the vehicle's electronic management system.
In particular, the ECM is responsible for sending signals to actuators that operate the fuel injectors and/or the throttle-body valve 24 of the vehicle 10 so that the combustible mixture supplied to the engine exhibits the instantly-desired air-to-fuel mass ratio (AFR). In this way, the ECM is able to continuously manage the AFR of the mixture of air and fuel that is supplied to the engine 12 in accordance with an engine control strategy. The quantity of fuel injected into the cylinders or into the incoming air flow may be controlled to maintain a predetermined lean AFR or a predetermined rich AFR, or to switch between the two modes of engine operation. Or, the amount of injected fuel may be controlled so that the AFR of the combustible mixture fluctuates in a narrow range, such as above and below the stoichiometric AFR.
The combustible mixture of air and fuel is supplied to cylinders 36 (usually four to eight) of the engine 12 and the various combustion products are expelled from the cylinders 36 of the engine 12 through an exhaust manifold 40 as an effluent exhaust stream 42 . The exhaust system 18 of the vehicle 10 comprises an enclosed and contained exhaust duct and exhaust treatment components that cooperate to receive the exhaust stream 42 from the engine 12 and to discharge a treated exhaust stream 44 from the tailpipe 46 to the ambient atmosphere. Treatment of the combustion products is accomplished by passing the exhaust stream 42 through various flow-through devices. For example, a typical exhaust system 18 of an automotive vehicle 10 includes a muffler 48 and a resonator 50 for reducing the amount of noise emitted by the exhaust system 18 . The exhaust system 18 of most engines also includes at least one catalyzed flow-through reactor to promote (1) the oxidation of CO to CO 2 , (2) the oxidation of HC to CO 2 and water, and (3) the reduction of NO X to N 2 and water in the effluent exhaust stream 42 from the engine 12 .
The exhaust system 18 shown in FIG. 1 illustrates three serially-arranged catalyzed flow-through reactors 52 , 54 , 56 located within the path of the exhaust stream 42 from the engine 12 . However, a variety of locations and arrangements are possible for the at least one catalyzed flow-through reactor of the exhaust system 18 . For example, each of the catalyst materials of the passive NH 3 -SCR exhaust treatment system may be located in separate flow-through reactors, or more than one of the catalyst materials may be housed within a single flow-through reactor. In addition, the flow-through reactors need not be arranged in a progressive series flow path. For example, the flow-through reactors may be arranged in parallel and a portion of the exhaust stream from the engine may be controlled to pass through one flow-through reactor, which the remaining portion of the exhaust passes through another flow-through reactor. Alternatively, the exhaust stream from the engine may be controlled to pass though some, but not all, of the flow-through reactors at a given time.
In the embodiment illustrated in FIG. 1 , the PGM catalyst powder may be washcoated within a first flow-through monolith reactor 52 , which is close-coupled to the exhaust manifold 40 of engine 12 . The CO-selective oxidation catalyst powder may be washcoated within a second flow-through monolith reactor 54 , which is positioned downstream of the first flow-through reactor 52 , relative to a flow direction of the exhaust stream 42 from the engine 12 . And the NH 3 -SCR catalyst powder may be washcoated within a third flow-through monolith reactor 56 , which is positioned downstream of both the first and second reactors 52 , 54 in an under-floor position. In this embodiment, an oxygen dosing or injection device 58 may be located upstream of the second flow-through reactor 54 , but downstream of the first flow through (PGM) reactor 52 . The oxygen dosing device 58 is preferably configured to inject an amount of oxygen into the flowing exhaust stream 42 before the exhaust passes over particles of the CO-selective oxidation catalyst.
In another embodiment, particles of a first NH 3 -SCR catalyst may be washcoated within a second flow-through monolith reactor 54 , which is positioned downstream of the first flow-through monolith reactor 52 in an under-floor position. And particles of the CO-selective oxidation catalyst and additional NH 3 -SCR catalyst may be washcoated within a third flow-through monolith reactor 56 , which is positioned downstream of both the first and second monolithic reactors 52 , 54 in an under-floor position. In this embodiment, the oxygen dosing device 58 may be located upstream of the third flow-through monolith reactor 56 , but downstream of the first and second flow-through monolith reactors 52 , 54 .
In yet another embodiment, particles of a first NH 3 -SCR catalyst may be washcoated within a second flow-through monolith reactor 54 , which is positioned downstream of the first flow-through monolithic reactor 52 in an under-floor position. And particles of the CO-selective oxidation catalyst and additional NH 3 -SCR catalyst may be washcoated within two flow-through reactors that are arranged in parallel and positioned downstream of both the first and second monolith reactors 52 , 54 in an under-floor position (not shown).
The operating temperature range of each of these catalysts during typical vehicle driving conditions can be controlled by adjusting the distance each catalyst-washcoated converter is located from the engine in the exhaust system. In general, the closer each catalyst-bearing support body is to the hot exhaust outlet of engine, the higher its operating temperature will be. In one embodiment, the PGM catalyst may be held within a reactor that is close-coupled to the engine so that, during normal driving conditions, the average temperature of the PGM catalyst is in the range of about 350-550° C. On the other hand, the CO-selective oxidation catalyst and the NH 3 -SCR catalyst may be held within at least one reactor that is positioned downstream of the PGM catalyst and under the vehicle floor, so that, during normal driving conditions, the average temperature of these catalysts is in the range of about 200-400° C.
In addition, particles of any one of these catalyst materials may be housed within multiple serially-arranged reactors (with some reactors being closer to the engine that others) so that some of the catalyst particles experience a relatively high-temperature operating range and the other catalyst particles experience a relatively low-temperature operating range. In this way, the architecture of the exhaust treatment system can be configured to cover a wide range of driving conditions.
By way of illustration, a suitable catalyzed flow-through reactor 60 for the passive NH 3 -SCR exhaust treatment system is shown in FIG. 2 . The catalyzed flow-through reactor 60 comprises an alloy steel container 62 shaped with an upstream opening 64 and a downstream opening 66 . The upstream opening 64 is configured to receive the exhaust stream 42 and the downstream opening 66 is configured to discharge the exhaust stream 42 . The body of the container 62 is often round or elliptical in cross-section and is sized to hold a catalyst-bearing support body 68 . The support body has an inlet face 70 and an outlet face 72 , which are transverse to the flow direction of the exhaust stream 42 . The support body 68 is held in place within the container 62 by a thermally insulating and physically durable mounting material 74 .
The support body 68 shown in FIG. 2 is an extruded ceramic, honeycomb-shaped monolith. However, other thermally stable materials, such as stainless steel, may be used to form other suitable high surface area support bodies. As shown in FIG. 2 , the extruded ceramic support body 68 includes several small, square, parallel flow-through channels 76 that are defined by walls 78 which extend longitudinally from the inlet face 70 to the outlet face 72 of the support body 68 . The inlet face 70 of the support body 68 is sized to provide a suitable number of channels 76 (preferably, at least 400 per square inch) to collectively accommodate a desired flow rate for the exhaust stream 42 , and, thus, a desired residence time of the exhaust gases within the support body 68 . In FIG. 2 , a portion of the container 62 , mounting material 74 and support body 68 have been cut-away to better reveal the many internal channel openings 76 and the channel walls 78 extending from the inlet to the outlet of the support body.
In practices of this invention, fine catalyst particles are deposited onto the walls 78 of the small flow-through channels 76 in the form of a thin washcoat layer or layers. The high total surface area of the many channel walls 78 provides sufficient contact surface area between the exhaust flow 42 and the catalyst particles for the desired oxidation, reduction and storage reactions to occur.
The exhaust flow may be exposed to other devices or mechanical equipment not expressly shown in FIG. 1 that may or may not help treat the exhaust gas constituents. These devices include, for example, a diesel particulate filter, a three-way-catalyst, a lean NO X trap, an exhaust gas recirculation line, and/or a turbocharger turbine. Skilled artisans will undoubtedly know of, and understand, these and the many other devices that the exhaust flow could be exposed to.
The above discussion with respect to FIGS. 1 and 2 describes locations for the subject selective carbon monoxide oxidation catalyst in an automotive vehicle in which the engine is being operated fuel-lean overall but with periodic fuel-rich cycles to generate sufficient ammonia for NO X reduction using an ammonia selective catalytic reduction reactor. The following disclosure pertains to the preparation of the mixed oxide catalyst and to its use in oxidation of CO in a gas stream also containing ammonia and oxygen.
EXAMPLE
In this example, particles of CeZrCuO X mixed oxides were prepared via a co-precipitation method. The CO and NH 3 oxidation activity of the as-prepared CeZrCuO X particles was then compared to that of a conventional Pd/Rh TWC catalyst. The Pd/Rh catalyst was obtained from BASF and had a Pd to Rh molar ratio of 6:1.
A precursor solution was prepared by dissolving metal nitrates of (NH 4 ) 2 Ce(NO 3 ) 6 , Zr(NO 3 ) 4 , and Cu(NO 3 ) 2 with molar ratios of 0.6:0.15:0.25 in deionized water at room temperature. Once the metal nitrates were dissolved in solution, the precursor solution was held with stirring for about 0.5 hours.
Next, a one molar sodium hydroxide solution was added to the precursor solution with vigorous stirring until its pH value reached 10 and a suspended co-precipitate of the base metals formed. The suspension was left at room temperature for 18 hours with mild stirring. Thereafter, the suspension was heated to 80° C. for 2 hours, and the co-precipitate was filtered from the liquid phase. The filtered precipitate was washed with hot deionized water, dried overnight at 110° C., and then calcined at 400° C. for 4 hours.
The CO and NH 3 oxidation activity of the as-prepared CeZrCuO X mixed oxide particles and the Pd/Rh particles was measured by placing 0.1056 cc of the respective catalyst powder in separate packed bed quartz tubular reactors, each having an outer diameter of ⅜ inch. A gas stream comprising 5000 ppmv CO, 1500 ppmv NH 3 , 5 vol. % CO 2 , 0.5 vol. % O 2 , 5 vol. % H 2 O, with N 2 as balance was fed in separate tests to each of the oxidation catalyst-filled tubular reactors through heated stainless steel lines at an hourly gas space velocity of SV=30,000 h −1 in each test.
The CO and NH 3 conversion performance of the CeZrCuO X catalyst and the Pd/Rh catalyst were separately measured, each over a temperature range of 100° to 550° C. The percent CO and NH 3 conversion values were calculated by comparing the concentration of CO and NH 3 in the gas stream at both the inlet ([CO] inlet or [NH 3 ] inlet ) and the outlet ([CO] outlet or [NH 3 ] outlet ) of each tubular reactor. Thus, the conversion (%) of CO or NH 3 is equal to [CO] inlet /[CO] outlet or [NH 3 ] inlet /[NH 3 ] outlet .
The percent conversion values of CO (solid line curve) and NH 3 dashed line curve) versus gas stream temperature for the Pd/Rh catalyst (for a conventional three-way catalyst) is presented graphically in FIG. 3 . Like data for the CeZrCuO X catalyst is presented in FIG. 4 . As shown in FIGS. 3 and 4 , both the Pd/Rh catalyst and the CeZrCuO X catalyst began oxidizing CO (solid line, both figures) at around 150° C. and reacted >90% CO conversion at about 225° C. The Pd/Rh catalyst began oxidizing NH 3 (dashed line, both figures) at around 210° C. and reached >90% NH 3 conversion at 225° C. But, the CeZrCuO X catalyst did not begin oxidizing NH 3 until around 375° C., and did not reach >90% NH 3 conversion until about 475° C.
It is found that similar CeZrCuO X catalyst compositions prepared in a like manner are likewise affective for the selective oxidation carbon monoxide in gas streams also containing ammonia and oxygen over temperature ranges of about 200° C. to about 400° C. In general, it is preferred that the molar ratios of Ce, Zr, and Cu in the particles of co-precipitated mixed oxides be controlled to fall within the following ranges: Ce a Zr b Cu c Ox where a has a value in the range of 0.50 to 0.70, b has a value in the range of 0.10-0.20, and c has a value in the range of 0.15-0.35, with the sum of these molar ratios of Ce, Zr, and Cu equal to 1. The value of x depends on the proportions and oxidation state of the metal elements but typically is in the range of about one to three.
Therefore, particles of CeZrCuO X mixed oxides can effectively be used to selectively oxidize CO in exhaust streams comprising carbon monoxide, ammonia, and oxygen, and having a temperature in the range of about 200° C. to 400° C., which is shown in FIG. 4 as the “CO Selective Oxidation Regime.” The gas stream may contain other non-interfering constituents such as water, carbon dioxide, and nitrogen. Under these conditions much of the carbon monoxide is oxidized to carbon dioxide and much of the ammonia is unaffected.
Practices of the invention have been described using illustrative examples which are not intended to limit the scope of the claimed invention.
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Particles of mixed oxides of cerium, zirconium, and copper (CeZrCuO X ) may be prepared as catalysts and used to preferentially catalyze the oxidation of CO in exhaust streams containing CO and NH 3 . In one practice, this CeZrCuO X catalyst may be used in combination with a close-coupled PGM catalyst which promotes the formation of NH 3 in the exhaust during fuel-rich operation, and at least one under-floor NH 3 -SCR catalyst, which catalyzes the reduction of NO X in the exhaust stream during fuel-lean operation using NH 3 as a reductant. During fuel-rich engine operation, the exhaust stream may be doped with oxygen downstream of the PGM catalyst and passed in contact with particles of the CeZrCuO X catalyst so that residual CO in the exhaust may be oxidized to CO 2 , without oxidation or other conversion of the NH 3 .
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BACKGROUND OF THE INVENTION
The refueling of vehicles, both in civilian and military usage, usually employs a supply hose having a manually operated nozzle having a spout insertable into the vehicle tank inlet neck through an inlet port. The nozzle valve is manually operated by a handle, and a tube within the spout senses the rising fuel within the inlet neck and automatically closes the nozzle valve upon sensing the presence of the fuel level to prevent overflow and spillage.
In military usage it is sometimes desirable that refueling of the vehicle occur while the vehicle engine is operating, and in such instance it is most important that fuel spillage be prevented. Furthermore, during military operations it may be necessary to refuel vehicles in unsecured locations where it is not desirable for the operator to be exposed to possible enemy fire for as long as a refueling operation may require.
While refueling nozzles are available which may not require the immediate attention of an operator, such nozzles must employ an automatic shut-off actuator to prevent overfilling, and premature operation of the automatic fuel level sensing shut-off apparatus often occurs which requires extra attention by the operator subjecting the operator to possible danger.
It is an object of the invention to provide automatic shut-off refueling nozzle structure utilizing an automatic fluid flow shut-off sensor wherein the nozzle valve is not prematurely actuated due to false back pressures within the tank inlet.
Another object of the invention is to provide a refueling nozzle having an automatic shut-off operation wherein dependable operation is achieved and contamination and spillage are prevented.
Yet another object of the invention is to provide an automatic shut-off refueling nozzle wherein spillage is prevented even though refueling occurs without attention by the operator.
A further object of the invention is to an provide automatic refueling nozzle employing a diverger for distributing nozzle flow to prevent premature valve actuation and wherein a secondary control valve is located within the diverger and is maintained in a closed condition until the nozzle is fully connected to the tank inlet.
In the practice of the invention a conventional automatic shut-off refueling valve is utilized in conjunction with spout-mounted structure achieving the purposes of the inventive concepts. The nozzle employed with both of the disclosed embodiments of the invention is of the conventional type such as used in civilian service stations wherein the nozzle is supplied with fuel under pressure through a hose and a manually operated trigger-type valve controls flow through the nozzle spout upon the spout being inserted into the fuel tank neck through the neck port. A sensing tube within the spout having an open end adjacent the spout end senses the presence of rising fuel at the spout end and through conventional back pressure sensing and actuation means closes the nozzle valve to prevent spillage.
The structure of the invention is mounted upon the spout and includes a lug plate concentrically rotatably mounted upon the spout having lug projections for cooperating with recesses and cam surfaces defined on the tank inlet neck port. Insertion of the spout end into the tank inlet neck port permits the lugs on the lug plate to engage the port recesses and rotation of the lug plate engages the lugs with the port cam surfaces to provide a positive connection between the lug plate and the tank neck end port.
Sealing structure is mounted upon the spout in proximity to the lug plate wherein the end of the tank neck at the port sealingly engages cap or cover structure mounted on the nozzle spout to prevent contamination of the fuel during filling. A vent passage defined through the lug plate permits venting of the tank during filling and the vent structure is so located as to prevent contamination.
As a nozzle in accord with the invention is used to refuel vehicles while the engine is running, and may be refueling military vehicles while the vehicles are under enemy fire, and the operator is taking cover, it is important that premature automatic closing of the nozzle during refueling does not occur. Such valve closing will occur if the flow of fuel into the fuel tank neck is such as to create a back pressure. To avoid premature nozzle shut-off a diverger is mounted upon the end of the spout structure having a plurality of orifices defined therein through which the fuel flows during operation. The orifices within the diverger are obliquely related to the axis of the tank neck and distribute the fuel flowing into the tank neck in such a manner as to prevent back pressure and premature nozzle valve closure.
In an embodiment of the invention a control valve is located within the diverger to prevent contamination of the spout when not in use, and close the orifices of the diverger with respect to the spout interior during nonuse. The control valve within the diverger is biased in a closed direction by a low pressure compression spring, and fluid flow through the spout will compress the spring and shift the control valve to an open condition permitting flow from the spout and through the diverger. The control valve is held in a closed condition by a plurality of radially displaceable detent balls held in a locked condition within the diverger and engaging the control valve by a retainer connected to the lug plate.
Upon the lug plate being rotated to the fully connected relationship to the tank inlet port the retainer releases the detents and thereby releases the control valve for displacement by the flowing fluid. Upon the termination of fuel flow the compression spring shifts the control valve to its closed position and upon the lug plate being rotated to permit release of the nozzle structure from the fuel tank port the detents will engage the control valve to lock it in the closed condition.
BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT
The aforementioned objects and advantages of the invention will be appreciated from the following description and accompanying drawings wherein:
FIG. 1 is an elevational view, partially in section, illustrating a nozzle utilizing the apparatus of the invention, as taken along Section I--I of FIG. 2, and illustrating the nozzle in alignment with a typical fuel tank inlet neck and port,
FIG. 2 is an elevational, sectional view as taken along Section II--II of FIG. 1,
FIG. 3 is an end elevational view of the tank inlet neck and port,
FIG. 4 is an elevational view of another embodiment of automatic shut-off nozzle in accord with the invention,
FIG. 5 is an enlarged, detail, partially sectioned, elevational view of the spout, spout connection structure, and diverger of the embodiment of FIG. 4 illustrating the components in the nonuse condition, and
FIG. 6 is an elevational, partially sectioned view similar to FIG. 5 illustrating the components in the operative fuel flowing condition as connected to a tank inlet port.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As represented in FIG. 1, a conventional automatic shut-off nozzle is represented at 10. This nozzle is of a conventional type, as used with civilian and military refueling systems and includes a shut-off valve 12 controlling fluid flow through a spout 14. The valve 12 is in communication with a pressurized fuel source such as a hose, not shown, via the chamber 16 defined in the nozzle and the manual position of the valve is determined by the trigger-type handle 18. A sensing conduit 20 is located in the spout 14 having a port 22 communicating with the outer surface of the spout and the conduit 20 communicates with pressure differential sensing structure within the nozzle 10, not shown, wherein the presence of a predetermined back pressure within the conduit 20 causes the valve 12 to automatically close regardless of the position of the valve operating handle 18. The aforementioned structure is commonly used in the fueling of vehicles to prevent spillage, and forms no part of the present invention.
The spout 14 comprises a cylindrical conduit having an open end 24, and a diverger 26 is mounted upon the spout open end to improve the fuel discharge flow characteristics. The diverger 26 includes an inner cylindrical bore 28 closely receiving the spout end and an annular sealing ring 30 establishes a fluid-tight seal relationship between the spout and diverger. The diverger includes a radial port 32 communicating with the nozzle back pressure conduit port 22 so as to establish communication between the conduit and the outer surface of the diverger, and a set screw 34 bears against the spout end and affixes the diverger in place. A plurality of orifices 36, usually three, are defined in the diverger circumferentially evenly spaced thereabout and the diverger orifices intersect the diverger end surface 38, and communicate with the end of the spout. As will be appreciated in FIG. 1, the axis of the orifices 36 is obliquely related to the axis of the spout and in this manner the fuel flowing through the diverger will be projected away from the nozzle and in an oblique outward direction against the walls of the tank inlet neck as later described.
The nozzle connection means includes synthetic plastic bearing sleeve 40 is mounted upon the spout adjacent the nozzle and the cap 42 is rotatably mounted upon the bearing sleeve. The cap 42 includes a cylindrical bore closely receiving the bearing, and a plurality of radially extending vanes 44 extend from the cap hub. The cap includes a radially extending flange portion 46 having an annular recess 48 defined therein. An annular retainer 50 is located upon the periphery of the cap flange 46 and is held in position by a drive wire 52 received within aligned recesses within the interior of the retainer and the exterior of the cap flange. Sealing structure is located within the cap recess 48 and includes a gasket 54, an annular piston 56, and an annular wave spring 58 engaging the radial face of the recess biases the piston to the left to impose a biasing force on the resilient gasket 54. The retainer 50 includes an annular shoulder for confining the gasket within the recess.
A lug plate 60 is attached to the cap hub by six cap screws 62 and the lug plate includes three radially extending lugs 64, FIG. 2, spaced at 120° locations about the periphery of the lug plate. The lug plate is provided with six axial holes 66 communicating with axial vent passages 68 defined in the cap 42 which intersect the cap vent ports 70. The vent ports are each closed with a screen 72 to prevent foreign particles from entering the fueling system.
The vehicle fuel tank to be refueled, not shown, includes an inlet neck 74, FIG. 1, having a port retainer 76 defined at its open end. The port retainer includes a bore 78, FIG. 3, having three notches 80 defined therein for receiving the lugs 64. A cam surface 82, FIG. 1, is defined in the port retainer adjacent each of the notches having a surface obliquely related to the axis of the neck 74. Thus, upon the lugs 64 being inserted through the notches 80, rotation of the lug plate 60 causes the lugs to ride upon the cam surfaces 82.
In use, the nozzle structure is aligned with the tank inlet neck 74 as shown in FIG. 1. The diverger 26 is inserted into the port retainer bore 78 until the lugs 64 engage the port retainer 76. Thereupon, the operator rotates the cap 42 in a clockwise direction, such rotation being readily facilitated by the rotatable mounting of the cap on the spout by the bearing 40 and the vanes 44. Upon the lugs 64 aligning with the port retainer notches 80 the lugs will enter the notches and continued rotation of the cap engages the lugs with the cam surfaces 82 tightly drawing the spout-mounted structure into the inlet neck and engaging the port retainer with the gasket 54. As the cap is rotated the wave spring 58 will be compressed as the port retainer moves into the recess 48 establishing a fluid-tight relationship between the end of the neck 74 and the cap 42.
The operator may now manually operate the nozzle handle 18 to open the valve 12 and permit fuel flow into the spout 14 and into the tank inlet neck 74 through the diverger orifices 36. As the fuel rapidly flows into the neck 74 through the orifices the fuel will be directed into the neck and against the neck walls away from the ports 32. The valve operating handle will include locking means for holding the actuating handle in an open condition and fuel may now flow at full capacity through the spout 14 into the neck 74 without attention by the operator. As the tank fills the air displaced by the fuel is exhausted from the neck through the vent holes 66 and cap vent passages 68.
Upon the tank filling the rising of the fuel within the neck produces a sufficient back pressure within the conduit 20 to trip the automatic shut-off apparatus closing the valve 12, and no spillage will occur. At his convenience the operator may then disconnect the nozzle 10 from the neck 74 by rotating the cap in a counterclockwise direction to align the lugs 64 with the notches 80 and withdraw the diverger and spout end from the tank neck. The aforementioned apparatus thereby permits refueling without attention by the operator, and premature nozzle valve closing and spillage is eliminated.
A variation of an automatic shut-off refueling nozzle in accord with the inventive concepts is shown in FIGS. 4-6, and in these figures apparatus similar to that previously described is indicated by primed reference numerals.
The spout 84 includes a tubular adapter or extension 86 of a cylindrical configuration and the adapter is internally threaded wherein the plenum 88 is threaded thereto. The automatic shut-off sensing conduit 20' communicates with the annular chamber 90 defined in the plenum and enclosed by the annular union 92 circumscribing the plenum.
An annular sleeve 94 circumscribes and is rotatably mounted upon the adapter 86, and the inner end of the sleeve 94 includes an annular handle 96 affixed thereto whereby the sleeve may be manually rotated by the handle. The exterior surface of the handle is provided with ribs and projections to improve frictional grip.
A cap 98 is affixed to the intermediate portion of the sleeve 94 adjacent the handle 96, and is fixed against axial displacement by the drive wire 100, and is sealed to the sleeve an O-ring. The cap 98 includes a web 102 having a plurality of vent holes 104 defined therein, and at its outer circumference the cap includes an annular bumper 106 formed of an elastomeric material, such as neoprene, and the bumper includes a flat radial sealing surface 108.
An annular lug plate or guide 110 having radial lugs 111 is mounted upon the outer end of the sleeve 94 for axial displacement relative to the sleeve, but the lug plate is keyed to the sleeve by a pair of axially extending dowels 112 whereby rotation of the sleeve produces rotation of the lug plate. An annular detent retainer 114 is threaded upon the lug plate and includes a forwardly extending nose portion having a inner detent retaining surface 116, and a recessed surface 118 radially outwardly spaced from the retaining surface 116. A compression spring 120 interposed between the lug plate and the union biases the lug plate and retainer 114 in a direction toward the cap 98.
An axially displaceable detent lock 122 is located upon the plenum 88 and is biased to the left by compression spring 124. The lock 122 is for the purpose of "lifting" the six detent balls 126 located within the diverger openings 128, as later described.
The hollow diverger 130 is threadedly affixed to the union 92 and includes a conical exterior surface 132, and an axial bore 134. A plurality of flow orifices 136 are defined in the diverger and externally intersect the surface 132, and internally communicate with the bore of the diverger. A spout valve 138 is located within the diverger having a sealing ring 140, and an annular detent receiving groove 142, and the spout valve is biased toward the right by the compression spring 144. The spout valve includes a guide stem 146 reciprocally received within the diverger bore 134. The compression spring 144 is relatively weak, and will compress under the force exerted on the spout valve by fuel flowing through the spout and through the diverger orifices. Upon cessation of fluid flow, the spring 144 will bias the spout valve 138 to the position shown in FIG. 5.
In the inoperative or nonuse condition the nozzle components will be as illustrated in FIG. 5. The spout valve 138 will be biased to the right by spring 144, and the seal ring 140 will engage the oblique valve seat 148 defined at the end of the plenum 88. In this manner the spout valve prevents foreign matter from entering the spout adapter or spout, and prevents any fuel within the spout from escaping. The spout valve 138 is held in its closed condition by the ball detents 126 which will engage the spout valve groove 142, FIG. 5, and will be held in the groove by the surface 116 of the retainer 114. The retainer 114 will be at its rightmost position, FIG. 4, in that the lug plate 110 will be biased to the right by spring 120.
When it is desired to connect the nozzle 10' to the tank inlet neck 74', FIG. 6, the diverger 130 will be aligned with the neck and inserted therein until the lug plate 110 engages the neck port retainer 76'. The lug plate is then rotated by handle 96 to align the lugs 111 with the port notches and continued rotation will cause the lugs to ride upon the inlet neck cams 82'. The cams 82' will, first, force the port retainer 76' into a sealed relationship with the bumper seal surface 108, and continued rotation of the handle 96 will displace the lug plate and retainer 114 to the left as shown in FIG. 6. Upon sufficient axial displacement of the retainer 114 to align the retainer surface 118 with the ball detents 126 the balls will be displaced outwardly by the ball lock 122 under the influence of the spring 124, and the balls will now be held within the diverger openings 128 by the lock 122 and retainer surface 118. Continued rotation of the handle 96 occurs until the lugs 111 have moved the desired distance upon the cam surfaces 82' to tighten the connection. Thereupon, the operator may open the nozzle valve 12' by the actuating handle 18' and the fuel pressure within the spout 84 will displace the spout valve 138 to the left, FIG. 6, permitting fuel to flow through the diverger orifices 136 into the neck 74'. Fueling will then continue automatically, and by the operator using the handle lock 150 unattended fueling is achieved. Vent holes 152 defined in the lug plate will vent the fuel tank to the atmosphere through the cap vent holes 104, and the sensing conduit 20' will sense the pressure, and liquid level, within the neck through the retainer openings 154, the union holes 156, and chamber 90.
Upon the fuel level rising to the retainer openings 154, the sensing conduit 20' will cause the nozzle valve 12' to close and fueling will be completed.
Upon the nozzle valve 12' closing, fluid flow and significant fuel pressure within the adapter 86 ceases permitting the spout valve 138 to be biased toward the right by spring 144, and the spout valve will move to the right engaging the detent lock 122 and displace the lock 122 to the right against spring 124 and seal 140 will seal against seat 148. The handle 96 is then rotated in a counterclockwise direction displacing the lugs 111 along the intake port cams 82' and the spring 120 will move the lug plate 110 toward the cap 98. This movement of the lug plate also displaces the retainer 114 to the right forcing the ball detents 126 inwardly into the spout valve groove 142. Upon complete unlocking rotation of the handle 96 the components will be shown as in FIG. 5 and the nozzle 10' may be removed from the tank inlet neck 74'.
By use of the spout valve 138 and the described structure the embodiment of FIGS. 4-6 will close the nozzle spout when not in use and provide additional protection against spillage and contamination.
It is appreciated that various modifications to the inventive concepts may be apparent to those skilled in the art without departing from the spirit and scope of the invention.
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The invention pertains to an automatic shut-off refueling nozzle particularly suitable for use with military vehicles employing a nozzle having a liquid level sensor operating a flow valve, the nozzle includes a lug plate attachable to the inlet of the tank receptacle being filled wherein once attached to the tank inlet the presence of an operator is not required during refueling. A diverger on the nozzle spout improves flow characteristics within the tank inlet to prevent premature release of the nozzle flow valve and the nozzle prevents contamination during refueling and prevents spillage of volatile fuels even though unattended. An embodiment of the invention utilizes a secondary control valve preventing fluid flow until the nozzle has been fully connected to the tank inlet.
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FIELD OF THE INVENTION
[0001] This Invention relates to hydraulically powered motors for accessory drives and more particularly to a new and improved multi-vane hydraulic motor with a hydraulically balanced rotor for improved high pressure performance and advanced pressurization of the undervane for quick and effective motor priming and efficient motor operation.
DESCRIPTION OF RELATED ART
[0002] Prior to the present invention a variety of hydraulic motors have been devised to provide improved drives in various systems such as the hydraulic accessory drive system in automotive vehicles. Many of such motors are multi-vane units that utilize a rotor with an arrangement of outwardly-extending and reciprocally-movable vanes that have cooperating springs for exerting a yieldable outward spring force on the vanes. This force fully maintains the vanes in good sealing and sliding contact with a surrounding outer cam for efficient motor operation. Some problems have been experienced with some motors with vane biasing springs in high cyclic and high speed operation. For example, the vane springs for engine cooling fan drive motors may fatigue and have shortened service life because of high speed and cycle actions during vehicle operation. Such spring fatigue may cause poor motor performance or break down.
[0003] [0003]FIG. 7 of the drawings of this application illustrates one prior art motor with spring biased radial vanes. Other examples are illustrated and described in U.S. Pat. No. 5,470,215 issued Nov. 28, 1995 to Stephen Stone for Wear Resistant Vane-Type Fluid Power Converter and U.S. Pat. No. 5,702,243 issued Dec. 30, 1997 to C. Richard Gulach for Hydraulic Motor with Pressure Compensated End Plates.
[0004] While such prior art hydraulic motors have generally met their objectives in providing improved operating characteristics, more economical and efficient motors are needed to meet requirements for a wider range of applications and to meet higher standards from an efficiency, service life and cost standpoints. Moreover, manufacture and assembly of prior art motors with their special vane and spring constructions are tedious, difficult and costly. New and improved motors are needed to alleviate such problems.
[0005] In contrast to the prior art multi vane hydraulic motors exemplified above, the present invention provides a new and improved hydraulic motor of straight-forward construction with effective and efficient routing of hydraulic motor drive pressures for quickly stroking the vanes into operative sliding-sealing engagement with a surrounding cam surface for quick motor priming. With the hydraulic biasing of the vanes of this invention, wear is materially reduced. This invention furthermore advantageously utilizes a minimal number of components particularly as compared to the prior art constructions with spring biased vanes.
[0006] This invention accordingly provides for the effective elimination of vane springs with the optimized employment of hydraulic forces instead of mechanical spring forces for yieldably stroking or urging the vanes into operative sealing engagement with an outer cam ring. Moreover with the quick stroking or “pop out” of vanes with high pressure hydraulics, initially fed at elevated points on the pressure grade curve to the undervane, the specialized prior art vanes and springs and their mechanical attachment are no longer required for quick and optimized motor priming. With the effective elimination of such springs and their attachment constructions, potential sources of motor wear and breakdown are eliminated.
[0007] In this invention high pressure hydraulic fluid from a hydraulic pump feeds into the inlet port of the motor and then into the high pressure side chambers or balancing pockets formed on opposing sides of the rotor of the motor. These side chambers are interconnected by the undervane passages so that a hydraulic pressure on opposing sides of the rotor is the same and rotor balancing is achieved. With such balanced rotor, motor breakdowns such as from rotor seizure experienced by prior unbalance rotors is minimized. The undervane passages in the rotor are formed at the inner ends of outwardly extending slots in the rotor. The vanes are mounted for reciprocal movement in these slots and the outer tips thereof operatively engage the cam surface of a surrounding cam ring mounted in the motor housing. The porting of high pressure flow into the rotor balancing chambers and interconnecting undervane passages of the rotor further forces the vanes outwardly and the tips of the vanes against the interior contour of the outer cam ring to effect an optimized sliding fluid seal.
[0008] In one preferred embodiment of this invention, an open ended housing is provided in which a specialized disk-like pressure plate is fixed at a predetermined distance from an internal end wall as determined by radial inner and outer o-ring seals to define a high pressure drive chamber therebetween located at one side of the rotor. The rotor is operatively mounted within the housing on an output shaft which extends axially therefrom for driving an accessory such as an engine cooling fan. The housing is closed by an end plate fixed thereto at the other side of the rotor which is formed with the inlet and outlet passages therein for the connection of hydraulic input and return lines thereto.
[0009] As the rotor is rotatably driven by the feed of pressurized hydraulic fluid from the high pressure drive chamber through one or more routing passages in the pressure plate into the vane chambers, the vanes reciprocate in their slots to establish an endless series of sealed rotor-drive chambers between adjacent vanes. These chambers serially receive pressure fluid from the system pump via the internal passages in the motor including the rotor balancing pressure chambers and the connecting undervane passages that feed into the high pressure drive chamber through inner passages in the pressure plate. The vane chambers subsequently discharge such fluid into an exhaust passage system in the end or cover plate and then to the return line operatively connected thereto.
[0010] The flow through the vane chambers with minimized leakage past the vane tip and cam seal effects rotation of the rotor and attached output shaft for accessory drive. Importantly in this invention the undervane passages receive pump pressure at high and optimum points on the pressure gradient for exerting an equal and outward force on each of the vanes optimizing and equalizing vane fluid sealing and wear. With improved vane-cam ring wear and sealing, pump operation is optimized.
[0011] These and other features, objects and advantages of the invention will become more apparent from the following detailed description and drawings in which:
[0012] [0012]FIG. 1 is a diagrammatic view of a hydraulic pump and motor system employed in a vehicle for driving accessories;
[0013] [0013]FIG. 2 is an end view of the hydraulic motor of FIG. 1 sight arrow A of FIG. 1 but with the pressure inlet port rotated out of position;
[0014] [0014]FIG. 3 is a cross sectional view of Fig. 2 but with some parts shown in full lines;
[0015] [0015]FIG. 3 a is an enlarged portion of the encircled part of FIG. 3 modified to illustrate an alternative structure of the invention;
[0016] [0016]FIG. 4 is a sectional view taken generally along sight lines 4 - 4 of FIG. 3 but with some parts shown in full lines and broken away;
[0017] [0017]FIG. 5 is a sectional view taken generally along sight lines 5 - 5 of Fig. 3 but with some parts shown in full lines and broken away;
[0018] [0018]FIG. 6 is a view of the pressure plate of the motor taken generally along sight lines 6 - 6 of Fig.3; and
[0019] [0019]FIG. 7 is a sectional view of a prior art spring-biased radial vane hydraulic motor.
DETAILED DESCRIPTION
[0020] Turning now in greater detail to the drawing there is schematically shown in FIG. 1 a vehicle engine cooling fan drive system 10 that is operatively integrated into the hydraulic power steering gear drive 12 . The steering gear drive includes a hydraulic pump 14 , that may be common to both power steering and fan drives and is driven by the vehicle engine, not shown. In addition to powering the power steering gear, the pump 14 is operatively connected by supply line 22 and return line 24 to power a hydraulic motor 26 . The return line 24 connects back into the pump 14 via to a fluid cooling radiator 28 and reservoir 30 as schematically shown. Controls for controlling the flow to the motor are not shown. The motor 26 may be supplied with pressure fluid from a pump dedicated thereto if desired.
[0021] The hydraulic motor 26 has an elongated, stepped-diameter output shaft 32 that rotatably drives a shrouded engine cooling fan 34 that effects the flow of air through an engine cooling radiator 36 operatively connected to a liquid cooled internal combustion engine, not shown, for engine cooling purposes. The hydraulic motor 26 , details of which are best shown in FIGS. 2 - 6 , comprises a generally cylindrical shell-like housing 38 which defines a cavity 40 in which a rotor 42 is operatively mounted. More particularly, the rotor is splined or otherwise mounted on the stepped diameter output shaft 32 that has it's innermost end rotatably mounted in bushing 43 or other suitable bearing supported in a mating cylindrical recess 41 in an end cover plate of the motor housing described hereinafter.
[0022] The output shaft 32 is further rotatably supported in the housing by a suitable bearing unit 42 axially spaced in the housing from the bushing 43 . A main lip seal 45 is mounted in a cylindrical recess in an outer extending cylindrical neck portion of the housing for annular sealing contact with the outer surface the output shaft.
[0023] The rotor, drivingly mounted by splines at its centralized inner bore to the output shaft 32 , is a generally cylindrical component formed with a circular periphery 44 . The periphery is of predetermined width matching the width of flattened, blade-like rotor vanes 46 associated with the rotor. The vanes 46 are operatively mounted in a plurality of generally linear slots 48 that preferably project radially in the rotor from a circular arrangement of inner and transversely extending undervane hydraulic passages 50 . Other slot arrangements, such as slots that are off center from the axis of rotor rotation may be used as desired.
[0024] The passages 50 extend from one side of the rotor to the other to hydraulically connect rotor balancing chambers 51 and 53 formed on opposite sides of the rotor described below. With a hydraulically balanced rotor 42 , rotor seizing is reduced or eliminated and motor operating efficiency is increased. When these balancing chambers and the connecting undervane hydraulic passages 50 are pressurized, the pressurized fluid in the undervanes exerts an equal outward force on each of the vanes for effecting the equal operative engagement of each the vane tips with the interior surface 52 of a cam ring 54 . The cam ring is securely fixed in the housing by dowel pins 55 and surrounds the rotor.
[0025] As best shown in FIGS. 3, 4 and 5 , the opposite sides of the rotor 42 are formed with preferably concentric inner and outer annular lands 56 and 58 and 56 ′ and 58 ′ that respectively cooperate with the flattened inner faces 60 of a disc-like pressure plate 62 mounted within the housing 38 by dowel pins 55 and the opposing flattened face 64 of a cover plate 66 that closes the housing. Threaded fasteners such as illustrated by reference numeral 62 in FIG. 2 secure the cover plate to the housing. While O-ring seal 69 provides fluid sealing between these two components. With the cover plate 66 secured to the housing 38 , the fluid pressure chambers 51 , 53 are formed between the annular lands on opposite sides of the rotor for rotor balancing purposes. Pressure fluid for motor operation is supplied from pump 14 via supply line 22 which connects into a hydraulic fitting 88 on cover plate 66 . The fitting connects to the radial passage 90 and transverse leg 92 in the cover plate for feeding high pressure fluid into the rotor balancing chambers and the interconnecting undervane.
[0026] The adjacent reciprocally movable vanes 46 further cooperate with the outer periphery of the rotor and the inner cam surface of the cam ring to define vane pressure chambers 74 in the motor so that the feed of high pressure hydraulic fluid thereto effects rotation of the rotor and thereby the drive of the fan. In FIG. 5 for instance, the high pressure of hydraulic fluid supplied to vane chambers 74 exerts a counter clockwise force on the rotor as it flows to the low pressure of the exhaust because of the area differential of adjacent vanes defining each vane chamber established by the cam surface as is well known in this art.
[0027] Fluid for driving the rotor is fed from high pressure drive chamber 78 (FIG. 3) formed in housing 38 between the pressure plate 62 and the facing end wall of the housing. The radial outer and inner limits of the high pressure chamber 78 are provided by outer and inner seal rings 80 and 82 of elastomer or other suitable material. The high pressure chamber 78 is supplied with pressure fluid by a pair of radially inner passages 83 in the pressure plate 62 for the direct feed of hydraulic fluid from the side rotor balancing chamber 51 into the high pressure drive chamber 78 .
[0028] As shown in FIG. 3, seal ring 82 is operatively mounted on an inner cylindrical neck 84 of the body of the housing and between the pressure plate and the facing inner wall of the housing. The outer sealing ring 80 is mounted between the pressure plate and the facing inner wall of the housing. With the high pressure drive chamber 78 established high pressure fluid is provided for feed through the vane chambers for the drive of the rotor.
[0029] Pressure fluid in the high pressure drive chamber is forced through one or more outer radial passages 98 in the fixed pressure plate (FIG. 5) and into the vane chambers 74 as they turn and serially pass such passages. These vane chambers exhaust as they pass arcuate discharge ports 100 cut or otherwise formed in the inner face of the cover plate. Pressure fluid discharged into ports 100 will flow back into low pressure such as provided by the exhaust or return line 24 through the transverse passage 102 and connected radial passage 104 in the cover plate. Passage 104 is connected by fitting 108 to the end portion of the return line 24 .
[0030] The radial bleed line 109 also formed in the cover plate connects the central opening 41 in the cover plate mounting the sleeve bearing 43 therein relieves the pressure in the opening for the output shaft 32 to provide relief and protection of the main seal 45 and for the circulating of the hydraulic fluid that act as a lubricating oil for the shaft and bearings.
[0031] In FIG. 3A, a modification to the motor primarily involving changes to the pressure plate is disclosed. In this modification the pressure plate 62 ′ is provided with spring-biased check valves 112 in the radially inner passages 83 ′ leading to the high pressure rotor drive chamber This check valve construction opens from the force of a predetermined pressure acting on the ball valve element of the check valve for effecting the build up of high pressure in the pressure balancing chambers for improved rotor balancing. Also the increased undervane pressure optimizes “pop out” of the vanes 46 to operatively engage the cam before the high pressure drive chamber 78 is fully charged.
[0032] In any event with this invention the motor vanes will be quickly “popped out” in response to the delivery of the high pressure from the pump 14 at a high point on the pressure gradient curve. With such response, the employment of spring devices such as vane springs 116 and their threaded rotor attachment fasteners 117 of FIG. 6 effecting the engagement of the vanes 11 8 with the cam 120 is not required. Moreover with the present invention, the force applied to each of the vanes is equal so that vane wear is equal for enhanced vane cam ring sealing and increased service life. With the prior vane spring and connections eliminated, unit build is simplified and motor performance is maintained at an optimized level with minimized breakdown.
[0033] Having described and illustrated preferred embodiments of this invention, various changes and modifications to the embodiments or the inventive concepts disclosed therein may be apparent to those skilled in the art without departing from the spirit or scope of the invention.
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A multi-vane hydraulic motor for accessory drive in which the vanes of a hydraulically balanced rotor are primarily urged into operative engagement with a surrounding cam by forces of the hydraulic fluid in undervane passage produced by an associated hydraulic pump to eliminate requirement for biasing springs and spring attachment of prior art motor. A high pressure chamber provided between the motor housing and a pressure plate mounted therein is hydraulically connected to the vane chambers of the rotor of the motor for the hydraulic drive thereof. An end cap closing the motor housing has the hydraulic input and output lines operatively connected thereto.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of application Ser. No. 12/789,255, filed May 27, 2010, now U.S. Pat. No. 8,066,692 which is a continuation of application Ser. No. 10/584,920, filed Dec. 28, 2006, now U.S. Pat. No. 7,758,566, which is the National Stage Entry of International Application No. PCT/US04/42723, filed Dec. 21, 2004, which claims the benefit of U.S. Provisional Application No. 60/532,916, filed Dec. 30, 2003; the entire contents of all of which are hereby incorporated by reference herein and made a part of this specification.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to medical systems specific to syringes.
2. Description of the Related Art
Syringes are commonly used to deliver medications and other biological fluids to a patient. The syringe typically has a plunger which is sealingly engaged with an outer cylindrical chamber to form an inner fluid—receiving chamber. A ‘male’ luer fitting is usually provided at a delivery end of the chamber which receives a female luer fitting with a needle assembly or the like. The fluid channel joining the cavity to the luer fitting is usually open, so that when the needle is removed, the cavity is open to the environment. This is problematic since many medications and biological fluids are sensitive (or can degrade when exposed) to the environment.
It is therefore an object of the present invention to provide a novel valve assembly for use with a syringe or other medical dispensing devices, enabling the latter to be closed to the environment when in an unattached condition.
SUMMARY OF THE INVENTION
In one of its aspects, the present invention provides a valve assembly comprising a male luer end portion, a female luer end portion and a channel for the transfer of fluids between the male and female luer end portions, valve means movable between a closed position and an open position, biasing means for biasing the valve means toward the closed position, and actuating means extending into the male luer end portion and coupled to the valve means to actuate the valve means when a female luer end portion of a medical accessory is coupled with the male luer end portion.
In an embodiment the male luer end portion has an inner projection and outer threaded sheath which is spaced therefrom to receive the female luer end portion therebetween. The actuating means includes an actuating member positioned between the outer threaded sheath and the inner projection.
In an embodiment, the valve means includes a valve seat and a valve member moveable relative thereto. The channel includes a first channel portion adjacent the female luer end portion and the inner projection includes a second channel portion. The valve member has a valve channel portion in fluid communication with the first and second channel portions. The valve seat is formed in the second channel portion and the valve member is integrally formed with the female luer end portion.
In one embodiment, the valve member includes an anchor flange extending outwardly toward an inner surface of the housing portion. In this case, the housing portion is coupled to the male luer end portion for movement therewith relative to the valve member. The male luer end portion engages the anchor flange when the valve means is in the closed position and the male luer end portion is spaced from said anchor flange when the valve means is in the open position. The housing portion terminates at an end region adjacent the female luer end portion, the biasing means includes a compression spring located within the housing between the end region and the outer anchor flange.
In another of its aspects, the present invention provides a medical dispensing device comprising a body having a chamber therein to contain a fluid material, a valve assembly in fluid communication with the chamber, the valve assembly having a male coupling member for engaging a female coupling member on a medical accessory to form a fluid coupling between the medical dispensing device and the medical accessory, the valve assembly further comprising flow control means operable to control fluid flow through the male coupling member, the flow control means being operable to be displaced by the female coupling member to open the male coupling member when female coupling member is operatively connected therewith, the flow control means being operable to be displaced by the female coupling member to close the male coupling member when the female coupling member is disconnected therefrom.
In one embodiment, the male coupling member includes an inner male portion and an outer sheath portion spaced therefrom to form a passage there between for receiving the female coupling member, the flow control means including at least one valve actuating portion positioned in the passage to abut the female coupling member and to displace the valve member during the travel of the female coupling member along the passage. The valve assembly includes a valve member and a valve seat, wherein the valve member is positioned against the seat to close the male coupling member. The valve actuating portion includes a pair of abutment elements which are spaced from one another along the passage to receive the female coupling member there between, wherein the pair of abutment elements are operable to travel with the female coupling member along the passage.
In one embodiment, the actuating portion is longitudinally oriented relative to the passage and the abutment elements are positioned along the actuating portion.
The valve member includes a back plate and a plurality of actuating portions equally spaced on the back plate, each of the actuating portions having first and second abutment elements.
In one embodiment, the valve actuating portion includes a locking flange which is adjacent one of the abutment elements. The valve assembly includes a locking seat to receive the locking flange when the male coupling member is in the closed position. The actuating portion has a distal end region, the locking flange being located adjacent the distal end region and the locking seat is formed in the outer sheath portion. The actuating portion is thus arranged to flex in order to displace the locking flange from the locking seat.
In yet another aspect, the present invention provides a medical dispensing device comprising a body having a chamber therein to contain a fluid material, a valve assembly in fluid communication with the chamber, the valve assembly having a male coupling member for engaging a female coupling member on a medical accessory to form a fluid coupling between the medical dispensing device and the medical accessory, the male coupling member including a projection and an outer valve member movable relative to the projection, the projection and the outer valve member forming a fluid channel there between, a sheath portion encircling the projection and spaced therefrom to form a passage to receive the female coupling member, the valve member being engageable with the female coupling member and movable relative to the projection to open the fluid channel when the female coupling member is connected with the male coupling member.
In one embodiment, the valve member forms an outer surface of the male coupling portion.
In an embodiment, biasing means is provided to bias the valve member toward an engaged position with the projection to close the fluid channel In this particular case, the passage ends at an inner wall and the biasing means includes a spring located between the inner wall and the valve member.
In one embodiment, the projection is fixed to the body and includes an inner passage, the inner passage having one end which is open to the chamber and another end which is open to the fluid channel. The projection also includes an enlarged end portion, the valve member including an outer portion arranged to engage the enlarged end portion to close the fluid channel. In this case the enlarged end portion and the outer end portion on the valve member have mating bevelled surfaces.
In one embodiment, the female coupling member has a leading segment, the valve member being dimensioned to fit within the leading segment.
Preferably, the medical dispensing device includes such items as a syringe, an IV bottle, an IV line, a powder and/or atomized fluid and/or gas inhalant dispenser, an implant delivery dispenser, a ventilator, a syringe pump, an intubation tube, a gastrointestinal feeding tube or a plurality and/or a combination thereof.
Preferably, the medical material is in solid, liquid or gaseous form or a combination thereof and has beneficial properties to enhance life, to promote health, to cure and/or treat a disease, condition or ailment, to monitor and/or indicate a bodily function or a combination thereof. For example, the medical material may be useful for, among others, IV therapy, implantation, stem cell therapy, oncology therapy, blood transfusion and/or organ transplantation.
BRIEF DESCRIPTION OF THE DRAWINGS
Several preferred embodiments of the present invention will now be described, by way of example only, with reference to the appended drawings in which:
FIG. 1 is a perspective view of a syringe assembly;
FIG. 2 is a sectional view of a portion of the assembly of FIG. 1 ;
FIGS. 3 and 4 are sectional views of the assembly of FIG. 1 in two alternate operative positions;
FIG. 5 is a fragmentary sectional perspective view of a portion of another syringe assembly;
FIGS. 6 and 7 are fragmentary perspective views of another syringe assembly;
FIGS. 8 to 12 are fragmentary sectional views of the syringe assembly of FIG. 6 ;
FIG. 13 is a fragmentary perspective view of yet another syringe assembly; and
FIGS. 14 and 15 are fragmentary sectional views of the syringe assembly of FIG. 13 or portions thereof.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the figures, and in particular FIG. 1 , there is provided a syringe assembly 10 comprising a syringe 12 and a valve unit 14 . The syringe 12 has a chamber 20 containing a plunger 22 to form a cavity 24 . Referring to FIG. 2 , the cavity has an outlet 26 and the valve unit 14 is located downstream of the outlet 26 for coupling the cavity 24 with a medical accessory such as a needle 30 (as shown in FIGS. 3 and 4 ). The valve unit 14 has an outlet 32 and flow control means, as will be described, to control fluid flow through the outlet, the flow control means being operable to open the outlet when the coupling section is operatively connected with the medical accessory, the flow control means being operable to close the outlet when the valve unit is disconnected from the medical accessory and to remain closed until connected once again with a medical accessory.
In this case, the chamber 20 includes a first male luer end portion 34 adjacent the outlet 26 and the valve unit 14 includes a first female luer end portion 36 which is engageable with the first male luer end portion 34 . The valve unit 14 also includes a second male luer end portion 38 for coupling with the medical accessory 30 .
Although the chamber 20 and the valve unit 14 are separate from one another in this case, it will be understood that they may, alternatively, be integrally formed, for example by combining the first male luer end portion 34 with the female luer end portion 36 .
The valve unit 14 has a channel 42 for the transfer of fluids between the first female and second male luer end portions 36 , 38 . A valve means, in the form of a valve member 44 is located in the valve unit 14 and is movable between a first position (as shown in FIG. 2 ), in which the channel is closed, and a second position (as shown in FIG. 3 ), in which the channel is open. An actuating means, in the form of an actuating member 46 (shown in FIG. 2 ), extends outwardly from the valve member 44 and into the second male luer end portion 38 . The actuating member 46 is coupled to the valve member 44 to actuate it when a female luer end portion of the medical accessory 30 is engaged with the second male luer end portion 38 .
In the embodiment of FIGS. 1 to 4 , the second male luer end portion 38 has an outer threaded sheath 50 which is spaced from an inner projection 52 . In this case, the actuating member 46 is positioned between the outer threaded sheath 50 and the inner projection 52 . The valve member 44 includes a valve plug portion 54 moveable relative to a valve seat portion 56 . The valve member 44 has an upper end which is integrally formed with the first female luer end portion 36 . An outer housing member 58 is slidably mounted on the valve member 44 . In this case, the outer housing member 58 is joined to the second male luer end portion 38 . The valve member 44 also has a valve channel 44 a extending from the first female luer end portion 36 to the valve plug portion 42 where it terminates at one or more transverse flow openings 44 b to join with the channel 42 .
The valve member 44 includes an anchor flange 60 , and the second male luer end portion 38 seats, directly or indirectly, against the anchor flange 60 when the valve is in the closed position as viewed in FIG. 2 . Conversely, the second male luer end portion 38 is spaced from said anchor flange when the valve is in the open position as shown in FIG. 3 .
The outer housing member 58 terminates at a radially inwardly directed end region 62 adjacent the first female luer end portion 36 and a biasing means in the form of a compression spring 64 is located within the outer housing between the end region 62 and the anchor flange 60 to bias the valve member toward the first position to close the valve unit.
An alternative arrangement is shown in FIG. 5 . In this case, the valve unit 70 has a housing 72 which is integrally formed with the female luer end portion 74 . A first channel portion 76 is adjacent the female luer end portion 74 and a second channel portion 78 is adjacent a male luer end portion 80 . In this case, the valve means includes a valve member 82 having a valve channel 84 in fluid communication with the first and second channel portions 76 and 78 . In this case, the valve seat portion is formed at 90 in the second channel portion 78 .
The valve member 82 includes a plug portion 92 which is movable relative to and within the second channel portion 78 for engaging the seat portion 90 to close the second channel portion 78 . The first channel portion 76 includes a tubular projection 94 extending from the female luer end portion 74 . In this case, the valve channel 84 in the valve member 82 is coextensive with the first and second channel portions 76 , 78 . In this case, the tubular projection 94 is slidably engaged with the valve member 82 within the valve channel 84 and sealed therein by way of seal 98 . Likewise, the valve member 82 is sealed within the second channel portion 78 by way of seal 100 .
The syringe assembly 10 is used as follows. First, the valve unit 14 is joined to the syringe 12 by engaging the corresponding first male luer end portion 34 with the first female luer end portion 36 . In this condition, the second male luer end portion 38 is unattached with a medical accessory such as the needle 30 and the actuating member 46 is fully extended into the second male luer end portion 38 as shown in FIG. 2 . Consequently, the valve member 44 is biased to its closed position, thereby engaging the valve plug portion 54 against the valve seat portion 56 .
The needle 30 is then attached to the syringe by engaging the female luer end portion on the needle 30 with the second male luer end portion 38 . Doing so causes the female luer end portion on the needle 30 to abut and displace the actuating member 46 , thereby causing the valve member 44 to be displaced upwardly (as viewed in FIG. 2 ) thereby releasing the valve plug portion 54 from its sealed abutment with the valve seat portion 56 to open the valve channel. The, plunger 22 may then be displaced outwardly to cause fluids in the proximity of the pointed end of the needle 30 to be drawn into the cavity 24 , by a path starting at the valve seat portion 56 through the channel 42 to the transverse flow openings 44 b , to the valve channel 44 a and on through the female luer end portion and into the cavity 24 . The needle 30 may then be removed causing the actuating member 46 to be displaced downwardly (as viewed in FIG. 2 ) causing the immediate displacement of the valve plug portion to abut the valve seat portion 56 and thereby close the valve.
Another device is shown at 120 FIGS. 6 to 12 , having a body 122 forming an inner chamber 124 therein to contain a fluid material. A valve assembly 126 is in fluid communication with the chamber 124 and has a male coupling member 128 for engaging a female coupling member 130 on a medical accessory (in this case a needle 132 ) to form a fluid coupling between the device 120 and the needle 132 .
The valve assembly 126 is operable to control fluid flow through the male coupling member 128 and more particularly to be in an open position when the male coupling member 128 is operatively connected with the female coupling member 130 and, conversely, to be in a closed position when the male coupling member 128 is disconnected from the female coupling member 130 .
In this case, the body 122 and the valve assembly 126 are integrally formed and, as seen in FIG. 8 , the latter includes a valve member 134 and a valve seat 136 . The valve member 134 is shown in its position against the valve seat 136 to close the male coupling member 128 , but for a very minor gap there between for illustrative purposes only.
The male coupling member 128 includes an inner male portion 140 having an inner fluid channel 140 a and an outer sheath portion 142 spaced from the inner male portion 140 to form a passage 144 there between for receiving the female coupling member 130 . At least one, in this case three, valve actuating portions 146 (two being shown in FIG. 7 ) are positioned in the passage 144 to abut the female coupling member 130 and to displace the valve member during the travel of the female coupling member 130 along the passage 144 . In this case, each valve actuating portion 146 is integrally formed with the valve member 134 . As shown in FIGS. 7 and 8 , the valve actuating portions 146 are prongs that extend from a back plate 160 .
Each valve actuating portion 146 includes a pair of abutment elements 150 , 152 which are spaced from one another along the passage 144 to receive the female coupling member 130 there between and to travel with the female coupling member along the passage 144 . The abutment element 152 has a bevelled outer surface 152 a for reasons to be described. Each valve actuating portion 146 is longitudinally oriented relative to the passage 144 and the abutment elements 150 , 152 are positioned along the valve actuating portion 146 .
Each valve actuating portion 146 includes a locking flange 154 and the valve assembly includes a locking seat 156 to receive the locking flange 154 when the valve member 134 is in the closed position. In this case, the actuating portion 146 has a distal end region and the locking flange 154 is located in the distal end region, while the locking seat 156 is formed in the outer sheath portion 142 . As shown in FIG. 8 , the locking seat 156 forms a shoulder in the outer sheath portion 142 having a first diameter closest to the end of the outer sheath portion 142 and a second diameter smaller than the first and spaced from the first diameter. As also shown in FIG. 8 the locking flange 154 comprises a protrusion and can engage with the locking seat or shoulder 156 .
It will be seen by comparing FIG. 9 and FIG. 10 , each actuating portion 146 is arranged to flex in order to displace the locking flange 154 out of the locking seat or shoulder 156 . Thus the actuating portion or prong 146 can form a hinge between the actuating portion and the back plate 160 . As can be seen by comparing FIGS. 9 and 10 , each of the prongs 146 is shown with a protrusion that moves along the outer sheath from the first inner diameter to the smaller second inner diameter, wherein the illustrated prongs are configured to rotate at the hinge when the valve member is moved to the open position from the closed position.
Referring to FIG. 8 , the valve member 134 includes a back plate 160 and the valve actuating portions 146 are equally spaced on the back plate 160 : The back plate 160 has a central fluid channel 162 which is in fluid communication with the chamber 124 and the valve member 134 has a fluid channel 163 therein in fluid communication with the central fluid channel 162 and hence the chamber 124 . In addition, the fluid channel 163 has a lateral portion 163 a which establishes fluid communication between the fluid channel 163 and an inner fluid channel 140 a in the inner male portion.
The device 120 is thus used as follows. The valve assembly is set with the valve member in its closed position, that is with the valve member 134 in its position against the valve seat 136 as shown in FIG. 8 . The female coupling member 130 on the needle 132 is aligned with the passage 144 and brought toward the male coupling member 128 . The bevelled outer or leading surface 152 a on the abutment member 152 aids to centre the female coupling member on the mouth of the passage 144 . With the locking flange 154 in the locking seat 156 , the female coupling member 130 is able to pass the lowermost edge of the abutment element 152 and continue into the passage 144 until the female coupling member makes contact with the abutment element 150 as seen in FIG. 9 . As seen in FIG. 10 , continued inward force on the female coupling member is transferred to the abutment element 150 causing the valve actuating portion 146 to move inwardly along the passage and thus to draw the locking flange 154 from this locked position in the locking seat 156 , causing the valve actuating portion 146 to flex, until the locking flange 154 is removed from the locking seat 156 . At this position, it can be seen that the valve member 134 has moved from the valve seat 136 to open the fluid channel 163 to the needle 132 .
Referring to FIG. 11 , as the female coupling member 130 is removed from the passage 144 , it makes contact with the abutment element 152 and causes the valve actuating portion 146 to move outwardly along the passage 144 and thus cause the valve member 134 to move toward the valve seat 136 . The locking flange 154 approaches, and finally enters, the locking seat 156 to coincide with the closure of the valve assembly.
Thus, the device 120 does not make use of a valve member which is biased to its closed position as with the earlier embodiment, but rather relies on the displacement of the female coupling member 130 to draw the valve assembly to its closed position when it is removed from the male coupling member 128 .
Another device is shown at 170 in FIGS. 13 to 15 , having a body 172 providing a chamber 174 therein to contain a fluid material. A valve assembly 176 is in fluid communication with the chamber 174 and has a male coupling member 178 for engaging a female coupling member 180 , again on a needle 181 , to form a fluid coupling between the medical dispensing device 170 and the needle 181 .
The valve assembly 176 is operable to control fluid flow through the male coupling member and more particularly to actuate or open the male coupling member 178 when operatively connected with the female coupling member 180 and, conversely, to close the male coupling member 178 when disconnected from the female coupling member 180 .
In this case, the male coupling member 178 includes a projection 182 which is fixed to the body 172 . A sheath portion 184 encircles the projection 182 and is also fixed to the body 172 . The sheath portion 184 and is spaced from the projection 182 to form a passage 186 to receive the female coupling member 180 .
A valve member 190 is movable relative to the projection 182 and forms a fluid channel 192 there between and sealed by an inner seal 193 . The projection 182 includes an inner passage 194 which has one end 194 a open to the chamber 174 and another end 194 b which is open to the fluid channel 192 .
Referring to FIGS. 14 and 15 , the projection includes an enlarged end portion 198 and the valve member 190 has an outer portion 200 arranged to engage the enlarged end portion 198 to close the fluid channel 192 . In this case, the passage 186 ends at an inner wall 202 and the valve member 190 is movable relative to the inner wall 202 under the action of a spring 203 which is positioned in the passage 186 between the valve member 190 and the inner wall 202 to bias the outer end portion 200 of the valve member 190 toward an engaged position with the enlarged end portion 198 .
As can be seen in FIG. 15 , the enlarged end portion 198 and the outer end portion 200 on the valve member 190 have mating bevelled surfaces 198 a and 200 a respectively.
The valve member 190 is operable to engage the female coupling member 180 and to travel with the female coupling member 180 along the passage 186 . In this case, the female coupling member 180 has a leading segment 180 a and the outer end portion 200 of the valve member 190 is dimensioned to fit within the leading segment 180 a.
In contrast to the device 120 of FIG. 6 , the device 170 has a valve member 190 which is biased to the closed position. As the female coupling member 180 passes over the projection 182 , the leading segment 180 a of the female coupling member 180 rides over the outer portion 200 of the valve member 190 . Continued inward displacement of the female coupling member 180 into the passage 186 thus causes the valve member to move relative to the projection 182 until the mating bevelled surfaces 198 a , 202 a separate to open the fluid channel 192 to the needle. The fluid coupling is thus fully operational when the female and male coupling members are tightly engaged. When the female coupling member 180 is removed from the male coupling member 178 , the valve member 190 is returned to its closed position against the projection 182 under the biasing action of the spring 203 , to close the male coupling member.
While the present invention has been described for what are presently considered the preferred embodiments, the invention is not so limited. To the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
The valve unit may be used with other medical fluid delivery devices, such as IV lines, catheters, infusion pumps and the like. The valve unit may also be used on syringes and other medical devices which do not employ the ubiquitous luer coupling arrangement.
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Disclosed herein is a syringe comprising a syringe body with plunger and a multi-pronged actuator. The syringe can further include a male coupling member, an outer sheath, a valve member and a back plate.
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FIELD OF THE INVENTION
[0001] The invention relates to mobility support of Internet-type protocol traffic in a communication system.
BACKGROUND OF THE INVENTION
[0002] Originally, Internet Protocol (IP) providing access to the Internet was designed for stationary users. Therefore, the basic IP concept does not support user mobility: The IP addresses are assigned to network interfaces depending on their location in the network. In fact, the first part of an IP address (NETID) is common to all interfaces that are linked to the same Internet subnetwork. This scheme prevents a user (a mobile host) from being reachable while moving over different Internet subnetworks, i.e. while changing the physical interface.
[0003] In order to enhance mobility on the Internet, Mobile IPs for IP version 4 (MIPv4) and IP version 6 (MIPv6) have been introduced by the Internet Engineering Task Force (IETF) in the standard RFC2002 and in the Internet Draft “Mobility Support in IPv6”, Jun. 25, 1999 (work in progress), respectively. A Mobile IP enables a mobile host to change its point of attachment from one Internet subnetwork to another without changing its IP address. The mobile IP introduces the following new functional or architectural entities. For the sake of brevity, the term ‘IP’ will hereafter refer to Mobile IP.
[0004] A ‘Mobile Node’ (MN) refers to a host that changes its point of attachment from one network or subnetwork to another. A mobile node may change its location without changing its IP address; it may continue to communicate with other Internet nodes at any location using its (constant) IP address.
[0005] A ‘Correspondent Node’ (CN) refers to a peer node with which a mobile node is communicating. The correspondent node may be either mobile or stationary.
[0006] A ‘Home Network’ is the IP network to which a user logically belongs. Physically, it can be, for example, a local area network (LAN) connected via a router to the Internet. A ‘Home Address’ is an address that is assigned to a mobile node for an extended period of time. It may remain unchanged regardless of where the MN is attached to the Internet. Alternatively, it could be assigned from a pool of addresses.
[0007] A ‘Home Agent’ (HA) is a routing entity that intercepts any packets destined to the mobile node's home address, while the mobile node is away from the home network. The HA encapsulates packets for delivering them to the mobile node, and maintains current location information for the mobile node.
[0008] In Mobile IPv4, a ‘Foreign Agent’ (FA) is a routing entity in a mobile node's visited network, which provides routing services to the mobile node while it is registered in that particular network, thus allowing the mobile node to utilize its home network address. The foreign agent decapsulates the packets that were encapsulated by the mobile node's home agent and delivers them to the mobile node. For datagrams sent by a mobile node, the foreign agent may serve as a default router.
[0009] RFC2002 defines a ‘Care-of Address’ (COA) for Mobile IPv4 as the termination point of a tunnel towards a mobile node for datagrams forwarded to the mobile node while it is away from home. The protocol can use two different types of care-of addresses: a “foreign agent care-of address” is an address announced by a foreign agent with which the mobile node is registered, and a “co-located care-of address” is an externally obtained local address which the mobile node has acquired in the network. An MN may have several COAs at the same time. A COA of a MN is registered with its HA. The list of COAs is updated when the mobile node receives advertisements from foreign agents. If an advertisement expires, its entry or entries should be deleted from the list. One foreign agent can provide more than one COA in its advertisements.
[0010] In Mobile IPv6, there is no longer a need to deploy special routers as FAs. Mobile nodes make use of the enhanced features of IPv6 to operate in any location away from home without requiring any special support from their local routers. Most packets sent to a mobile node away from home in Mobile IPv6 are routed using an ‘IPv6 Routing’ header rather than IP encapsulation, whereas Mobile IPv4 must use encapsulation for all packets. The use of a Routing header requires less overhead for Mobile IP packet delivery from a CN to an MN. To avoid modifying the packet in flight, however, packets intercepted and routed via a mobile node's home agent in Mobile IPv6 must still use encapsulation for delivery. The COA in Mobile IPv6 is the IP address associated with a mobile node while it is visiting a foreign network.
[0011] Both in Mobile IPv4 and in Mobile IPv6, the term ‘Mobility Binding’ is the association of a home address with a care-of address, along with the remaining lifetime of that association. An MN registers its COA with its HA by sending a registration request message. In IPv4, the ‘IPv4 Registration Request’ message may be relayed to the HA by the foreign agent through which the mobile node is registering, or it may be sent directly to the HA if the mobile node is registering a co-located care-of address. The HA returns an ‘IPv4 Registration Reply’ message to the mobile node which has sent an IPv4 Registration Request message. If the mobile node has registered by using a foreign agent care-of address, the IPv4 Registration Reply is delivered to the mobile node via the foreign agent. The IPv4 Reply message informs the mobile node about the status of its IPv4 Request. Optional extension fields containing additional information concerning the connection may be included in the IPv4 Registration Request and Reply messages. In IPv6, a mobile node sends a registration request message directly to the HA, and in response to the request message, the HA returns a registration reply message to the mobile node. The registration request and reply messages are included in a ‘Destination Options’ header, which is used to carry optional information that needs to be examined only by the destination node. The messages are called ‘Binding Update’ and ‘Binding Acknowledge’, respectively.
[0012] In order to enable full IPv6 functionality of isolated IPv6 nodes in an IPv4 environment, a ‘6over4’ transmission method has been introduced in IETF standard RFC2529. The principle is that IPv6 packets are encapsulated in IPv4 packets for transmission over the IPv4 network between isolated IPv6 nodes.
[0013] A real advantage of IPv6 over IPv4 is that the former contains routing optimization by default, i.e. the home agent is involved only when the first datagram is sent to the mobile node on the connection initiation, hence reducing the overhead required. However, an IPv6 network is not available everywhere and not all user terminals are equipped with IPv6 compatibility. Since the addressing schemes in the two versions are incompatible, the IPv4 and IPv6 nodes cannot communicate with each other in a straight-forward manner.
DISCLOSURE OF THE INVENTION
[0014] An object of the invention is to develop a method and a communication system which provide mobile nodes with means for communicating over networks supporting different IP versions and with means for being simultaneously addressable with IP addresses according to at least two different IP versions irrespective of the type of the particular network that the mobile node is attached to.
[0015] This object is achieved with a method and a system which are characterized by what is disclosed in the attached independent claims. Preferred embodiments of the invention are disclosed in the attached dependent claims.
[0016] According to a preferred embodiment of the present invention, a mobile node is arranged to handle data packets at least according to two different IP versions and to have a home address at least according to said two IP versions. The home agent is provided with means for intercepting all data packets destined to the mobile node irrespective of the original IP version of the data packets. In the home agent, a data packet addressed to the mobile node is encapsulated in a packet according to the IP version of the foreign network with which the mobile node is registered, for routing the data packet to the mobile node. This method improves the employment of the network resources.
[0017] According to a further preferred embodiment of the present invention, a mobile node is registered with at least a first and a second foreign network so that the respective first and second care-of addresses are simultaneously active in the home agent of the mobile node, and data packets according to at least the first and the second IP version are routed to the mobile node (MN) via the home agent by using the IP version of the first and the second foreign network respectively. This embodiment can be implemented by means of a new extension field in the registration request message. The advantage of this method is smaller overhead in the visited network.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In the following, the invention will be described in greater detail by means of preferred embodiments with reference to the accompanying drawings, in which
[0019] [0019]FIGS. 1A and 1B illustrate scenarios where a mobile node in an IPvY foreign network communicates with a correspondent node in an IPvZ subnetwork, Y and Z being different version numbers,
[0020] [0020]FIGS. 2A and 2B illustrate scenarios where a mobile node is registered with an IPv4 foreign network,
[0021] [0021]FIG. 3 illustrates a scenario where a mobile node is registered with an IPv6 foreign network,
[0022] [0022]FIG. 4 is a signaling diagram illustrating data transfer between an MN in an IPv4 foreign network and a CN in an IPv6 subnetwork,
[0023] [0023]FIG. 5 is a signaling diagram illustrating data transfer between an MN in an IPv6 foreign network and a CN in an IPv4 subnetwork,
[0024] [0024]FIGS. 6A and 6B illustrate scenarios where a mobile node registers with both IPv4 and IPv6 foreign networks,
[0025] [0025]FIG. 7 is a signaling diagram illustrating the registration of the MN when the MN first registers with an IPv6 foreign network,
[0026] [0026]FIG. 8 is a signaling diagram illustrating the registration of the MN when the MN first registers with an IPv4 foreign network,
[0027] [0027]FIG. 9 is a signaling diagram illustrating data transfer when the MN is registered with both IPv4 and IPv6 foreign networks, and
[0028] [0028]FIG. 10 illustrates a registration request message according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0029] The present invention can be generally applied to a network that includes at least two subnetworks supporting different IP versions for providing IP mobility over the subnetworks. The invention can be used especially preferably for providing IP mobility over IPv4 and IPv6 subnetworks. In the following, preferred embodiments of the invention will be described by means of said IP versions without limiting the invention to these particular IP versions.
[0030] The network may be, for example, a local area network (LAN) or any other kind of network providing data connections. The network may be either wireless or fixed. The greatest advantages are achieved in a network providing a relatively slow data connection. The MN may consist of a laptop computer PC connected to a mobile station radio or some other type of mobile workstation construction. Alternatively, the MN can be an integrated combination of a small computer and a cellular telephone, similar in appearance to the Nokia Communicator 9000 series. Yet further embodiments of the MN are various pagers, remote-control, surveillance and/or data-acquisition devices, etc.
[0031] [0031]FIGS. 1A and 1B illustrate simplified scenarios where a mobile node MN is attached to a foreign network 16 supporting IP version Y. A correspondent node CN is attached to a subnetwork 14 supporting IP version Z and another correspondent node CN′ is attached to a subnetwork 18 supporting IP version Y. The mobile node MN is provided with a home address according to IP versions Y and Z and with means to handle data packets according to both versions. A home agent HA in said mobile node's MN home network 12 intercepts all packets destined to the mobile node MN regardless of their type and the type of the foreign network with which the mobile node MN is registered.
[0032] In FIG. 1A, the home agent HA encapsulates an IPvY data packet destined to the mobile node's IPvY home address normally in an IPvY data packet IPvY[IPvY] and an IPvZ data packet destined to the mobile node's IPvZ home address in an IPvY data packet IPvY[IPvZ] for delivery to the mobile node MN. The data packets IPvY[IPvY] and IPvY[IPvZ] are routed directly to the mobile node MN. In FIG. 1B, the mobile node MN is registered with the IPvY foreign network via a foreign agent FA and the data packets are routed to the mobile node MN via the foreign agent FA. The home agent HA encapsulates an IPvY data packet destined to the mobile node's IPvY home address normally in an IPvY data packet IPvY[IPvY] for delivery to the mobile node MN via the foreign agent FA. The home agent HA also encapsulates an IPvZ data packet destined to the mobile node's IPvZ home address in an IPvY packet for the mobile node MN and further in another IPvY packet for the foreign agent FA, resulting in a multiply-encapsulated data packet IPvY[IPvY[IPvZ]]. Therefore, both in FIG. 1A and in FIG. 1B, the correspondent node CN may send data packets according to IP version Z to the mobile node MN without any address transformation, even though the mobile node MN is not attached to a network supporting IP version Z.
[0033] [0033]FIGS. 2A, 2B and 3 illustrate simplified scenarios where a mobile node MN and a correspondent node communicate over IPv4 and IPv6 subnetworks. The mobile node MN is provided with means to operate both in IPv4 and IPv6 networks, i.e. to have an IP address according to both protocol versions. In other words, the mobile node MN is always addressable from an external network by both the IPv4 and the IPv6 address. The mobile node's home agent HA in a home network 22 is arranged to intercept IPv4 and IPv6 packets destined to the mobile node MN regardless of their type. In FIGS. 2A and 2B, the mobile node MN is attached to an IPv4 foreign network 26 and a correspondent node CNv 6 is attached to an IPv6 subnetwork 24 .
[0034] In FIG. 2A, the mobile node MN is registered with the IPv4 foreign network 26 via a foreign agent FA. The home agent HA encapsulates an incoming IPv6 data packet in an IPv4 packet for the mobile node MN and the latter in another IPv4 packet for the foreign agent FA, resulting in a multiply-encapsulated data packet IPv4[IPv4[IPv6]]. In FIG. 2B, the mobile node MN is registered with the IPv4 foreign network without a foreign agent FA. The home agent HA encapsulates an incoming IPv6 data packet in an lPv 4 packet for the mobile node MN, resulting in a data packet IPv4[IPv6].
[0035] In FIG. 3, the mobile node MN is attached to an IPv6 foreign network 36 and a correspondent node CNv 4 is attached to an IPv4 subnetwork 34 . The home agent HA encapsulates an incoming IPv4 data packet in an IPv6 packet for the mobile node MN, resulting in a data packet IPv6[IPv4].
[0036] [0036]FIG. 4 is a signaling diagram illustrating data transfer in a scenario according to FIG. 2A. Prior to the data transfer, the mobile node MN registers normally with the IPv4 foreign network. All IPv4 data packets destined to the mobile node MN are routed normally according to the Mobile IPv4 and therefore are not considered here. In step 4 - 1 , the correspondent node CNv 6 sends an IPv6 data packet to the mobile node's MN IPv6 address. The home agent HA intercepts the packet and encapsulates it in an IPv4 packet for the mobile node MN and the latter in another IPv4 packet for the foreign agent FA, resulting in a multiply-encapsulated packet IPv4[IPv4[IPv6]] in step 4 - 2 . The foreign agent FA then decapsulates the outer IPv4 packet and forwards the remaining data packet IPv4[IPv6] to the mobile node MN in step 4 - 3 . In the mobile node MN, the remaining IPv4 packet is decapsulated by an IPv4 stack and the original IPv6 packet is forwarded to an IPv6 stack for normal processing in step 4 - 4 . In the other direction, the IPv6 stack in the mobile node MN produces an IPv6 datagram and forwards it to the IPv4 stack in step 4 - 5 . In step 4 - 6 , the IPv4 stack encapsulates the original IPv6 packet into an IPv4 packet and sends the resulting packet IPv4[IPv6] for example to the home agent HA that decapsulates the IPv4 packet and forwards the original IPv6 packet to the correspondent node CNv 6 in step 4 - 7 .
[0037] [0037]FIG. 5 is a signaling diagram illustrating data transfer in a scenario according to FIG. 3. Now the mobile node MN registers with the IPv6 foreign network in a normal way, and all IPv6 data packets destined to the mobile node's MN IPv6 home address are routed normally. In step 5 - 1 , the correspondent node CNv 4 sends a data packet IPv4 to the mobile node's MN IPv4 address. The home agent HA intercepts the packet and encapsulates it in an IPv6 packet for the mobile node MN, resulting in a packet IPv6[IPv4] n step 5 - 2 . In the mobile node MN, the IPv6 packet is then decapsulated by an IPv6 stack and the original IPv4 packet is forwarded to an IPv4 stack for normal processing in step 5 - 3 . In the other direction, the IPv4 stack in the mobile node MN produces an IPv4 datagram and forwards it to the IPv6 stack in step 5 - 4 . In step 5 - 5 , the IPv6 stack encapsulates the original IPv4 packet into an IPv6 packet and sends the resulting packet IPv6[IPv4] for example to the home agent HA that decapsulates the IPv6 packet and forwards the original IPv4 packet to the correspondent node CNv 4 in step 5 - 6 .
[0038] Instead of routing MN-originated packets via the HA (steps 4 - 6 and 5 - 5 ), such packets may be routed via any other router or entity that is equipped with means to identify, decapsulate and forward a packet.
[0039] [0039]FIGS. 6A and 6B illustrate scenarios according to a further embodiment of the invention. The mobile node MN is registered simultaneously with an IPv4 foreign network 64 and an IPv6 foreign network 66 . If both types of foreign networks are available, the mobile node MN retains its attachment to the foreign network it has already registered with and registers also with the other one. Similarly to the scenarios in FIGS. 2A, 2B and 3 , the home agent HA intercepts all packets IPv4, IPv6 destined to the mobile node MN regardless of their type. In FIG. 6A, the mobile node MN is registered with the IPv4 foreign network via a foreign agent FA. The home agent HA encapsulates an IPv4 datagram in an IPv4 packet IPv4[IPv4] for the foreign agent FA, which forwards the original IPv4 packet to the mobile node MN. Correspondingly, the home agent HA encapsulates an IPv6 datagram in an IPv6 packet IPv6[IPv6] for the mobile node MN. In FIG. 6B, the mobile node MN is registered with the IPv4 foreign network without a foreign agent FA. Now the home agent HA encapsulates an IPv4 datagram in an IPv4 packet IPv4[IPv4] directly for the mobile node MN. Similarly to FIG. 6A, the home agent HA encapsulates an IPv6 datagram in an IPv6 packet IPv6[IPv6] for the mobile node MN. In this way, unnecessary encapsulations are eliminated and overhead for the foreign networks is reduced.
[0040] [0040]FIG. 7 is a signaling diagram illustrating the registration of the mobile node MN in a scenario according to FIG. 6A when the mobile node MN first registers with the IPv6 foreign network. Steps 7 - 1 and 7 - 2 illustrate normal registration with the IPv6 foreign network. Steps 7 - 3 to 7 - 6 illustrate registration with the IPv4 foreign network via a foreign agent with a ‘Simultaneous IPv6 Binding’ extension. The extension is similar to for example the ‘Encapsulating Delivery Style’ extension header and includes the IPv6 care-of address that will be used simultaneously with the IPv4 care-of address.
[0041] [0041]FIG. 8 is a signaling diagram illustrating the registration of the mobile node MN in a scenario according to FIG. 6A when the mobile node MN first registers with the IPv4 foreign work. Steps 8 - 1 to 8 - 4 illustrate normal registration with the IPv4 foreign network via a foreign agent. Steps 8 - 5 and 8 - 6 illustrate the registration with the IPv6 foreign network with a ‘Simultaneous IPv4 Bindings Destination Option’ extension including the IPv4 care-of address that will be used simultaneously with the IPv6 care-of address.
[0042] In FIG. 9, data transfer in a scenario according to FIG. 6A is illustrated in the form of a signaling diagram. The correspondent node CNv 6 sees the mobile node MN as an IPv6 node and the correspondent node CNv 4 sees the mobile node MN as an IPv4 node. Steps 9 - 1 to 9 - 5 illustrate traffic between the correspondent node CNv 6 and the mobile node MN and steps 9 - 6 to 9 - 9 illustrate traffic between the correspondent node CNv 4 and the mobile node MN.
[0043] [0043]FIG. 10 illustrates a registration request message 101 according to the present invention used for simultaneous registration with an IPv4 and an IPv6 foreign network. The first part 102 of the message 101 is a normal registration request. In Mobile IPv4, the part 102 is called an IPv4 Registration Request message, and in Mobile IPv6 said part 102 is called a Binding Update and is included in a Destination Options header. The second part 103 of the message 101 is an extension including the care-of address which is to be used simultaneously with the care-of address according to the first part 102 of the message 101 .
[0044] This description only illustrates the preferred embodiments of the invention. The invention is not, however, limited to these examples, but it may vary within the scope and spirit of the appended claims.
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A method for routing data packets to a mobile node in a communication system which includes at least a first subnetwork of a first type supporting a first IP version and a second subnetwork of a second type supporting a second IP version. The mobile node is provided with a set of protocol stacks for handling data packets at least according to the first and the second IP version and with a home address at least according to the first and the second IP version. The home agent is provided with means for intercepting at least data packets addressed to the mobile node's home address according to the first or the second IP version and for encapsulating a data packet addressed to the mobile node in a packet according to the IP version of the foreign network to which said mobile node is attached, for routing the data packet to the mobile node.
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FIELD OF THE INVENTION
This invention relates to a cooling apparatus for knitting components (needle cylinder, cam holder, needle-selecting actuator and other peripheral parts) in a circular knitting machine.
BACKGROUND OF THE INVENTION
When a circular knitting machine is in operation, frictional heat is generated between its components. The frictional heat causes thermal expansion and deformation of the components. Such expansion and deformation cause damage to knitting tools such as knitting needles and jacks, and brings about abnormalities of the needle selecting apparatus, producing pattern errors. This is a long-standing problem, which has become more serious in recent years. The speed of operation is increasing, and knitting machines are getting larger and larger, resulting in greater thermal friction. The increase in the use of electronic parts has also added to the amount of heat generation.
As a way of solving this problem, a number of methods for cooling the cylinder by air or water were proposed in the past.
For example, JP-A-4-245963 (1992) discloses a cylinder that is provided with a fluid path through which the air or fluid medium can flow to cool the cylinder. Forming a fluid path directly on the cylinder, however, entails a high manufacturing cost. It is also suspected that the direct cooling effect extends only to the cylinder, leaving the peripherals insufficiently cooled.
According to JP-A-6-287844 (1994) by the present applicant, an orifice is provided between the cylinder and the fabric in the lower part of the knitting section of the knitting machine to cool the cylinder and its peripherals as well as to remove and discharge fiber dust, etc. According to this prior invention, not only the cylinder but also the peripherals are cooled.
According to JP-A-10-60759 (1998), an annular air chamber is established between the cylinder and the dial, and a pressurized airflow is fed into it. The invention of this Japanese application was originally intended to provide an apparatus for preventing airborne cotton or dust, and the cooling of the knitting components per se is not mentioned at all in the specification. However, as long as an airflow is generated around the cylinder, a cooling effect on the cylinder would be expected. At first glance, this configuration resembles that of the present invention. Therefore, this prior apparatus will be discussed further in the section describing the effects of the prior apparatus by way of comparison with the present invention.
SUMMARY OF THE INVENTION
It is an object of the present invention to produce an apparatus that exhibits an improved cooling effect on the knitting components as an improvement on the apparatus disclosed in the above-mentioned JP-A-10-60759 (1998).
The cooling apparatus for knitting components in a circular knitting machine of the present invention is a cooling apparatus for knitting components in a circular knitting machine equipped with a needle selecting actuator for knitting a jacquard fabric. The needle selecting actuator is surrounded by an upper shield at the top, a lower shield at the bottom, a needle cylinder inside and a cover outside, and a cylindrical chamber is formed between the needle selecting actuator and the cover. The cover is equipped with ventilation means for feeding the air into the cylindrical chamber, and the cylindrical chamber has an opening through which the air passes. In this way, the outside air is fed into the cylindrical chamber by the ventilation means and passes through the opening to cool the needle cylinder and its peripheral knitting components.
The opening of the cylindrical chamber is, for example, a gap in the periphery of the cover. It is preferable to form the upper end of the cover in an inverted L shape orientated towards the other peripheral working components. The size of the gap in the periphery of the cover is, for example, 5-50 mm.
The opening of the cylindrical chamber can also consist of holes that penetrate the upper shield. These holes are preferably slanted so as to be orientated towards the other peripheral working components. The size of each hole is, for example, 5-20 mm, and the number of holes is, for example, 10-100.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross sectional view of the knitting section of a circular knitting machine according to a first embodiment of the present invention.
FIG. 2 is a cross sectional view of the knitting section of a circular knitting machine according to a second embodiment of the present invention.
FIG. 3 is a cross sectional view of the knitting section of the circular knitting machine (according to the first embodiment of the present invention shown in FIG. 1) showing the points at which temperatures are measured for an effect-comparison test.
FIG. 4 is a perspective view of the knitting section of the circular knitting machine according to the first embodiment of the present invention shown in FIG. 1 .
FIG. 5 shows a modified example of the upper end of the cover for the knitting section of the circular knitting machine according to the first embodiment of the present invention.
FIG. 6 shows another modified example of the upper end of the cover for the knitting section of the circular knitting machine according to the first embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiments of the present invention will now be described by reference to the accompanying drawings.
FIG. 1 is a cross sectional view of the knitting section of a circular knitting machine according to the first embodiment of the present invention. The knitting section is established above a bed 1 which is supported by a number of legs (not shown). The main components of the knitting section are the cylinder needle part, the yarn carrier part, the actuator part and the knitting needle controlling cam part.
In the cylinder needle part, a cylinder needle (not shown) is disposed in such a way that it is vertically slidable along a needle groove (not shown) formed on the periphery of a rotary needle cylinder 2 . The rotary needle cylinder 2 rotates at the same speed as a gear ring 3 which is positioned beneath the needle cylinder 2 . In the yarn carrier part, a yarn carrier 4 feeds yarn to the knitting needle. In the actuator part 5 , needles are selected in such a way as to give variety to the knit fabric. In the cylinder needle controlling cam part, a cam (not shown) housed in a cylinder cam holder 6 imparts a vertically reciprocal movement to the cylinder needle.
The cylinder cam holder 6 is supported by an annular intermediate ring 7 , and the intermediate ring is further supported by the bed 1 via a support 8 . The actuator 5 is established on a lower ring 9 which is fastened to the bed.
The machine shown in FIG. 1 is a double-knit circular knitting machine, which also has a dial needle part and a dial needle controlling cam part. In the dial needle part, a dial needle (not shown) is disposed in such a way that it is horizontally slidable along a needle groove formed on the upper surface of a needle dial 10 . In the dial needle controlling cam part, a cam (not shown) housed in a dial cam holder 11 imparts a horizontally reciprocal movement to the dial needle.
On the peripheral side of the space between the intermediate ring 7 and the lower ring 9 , a cylindrical cover 12 is mounted. This cover 12 forms a cylindrical chamber 13 which is enclosed by the intermediate ring 7 at the top, the lower ring 9 at the bottom, and the actuator 5 and the cover 12 at the sides.
The lower end of the cover 12 makes contact with the lower ring 9 , while the upper end is positioned slightly above the upper surface of the intermediate ring 7 . The top portion 12 a of cover 12 has an inverted L shape in cross-section. Between this inverted L shaped top portion 12 a and the upper surface of the intermediate ring, there is established an opening 14 that opens to the cylinder cam holder 6 , while a gap 15 is also established between the periphery of the intermediate ring and the cover 12 so that the air flow is not obstructed. The size of the opening 14 and the gap 15 is preferably 5 to 30 mm, more preferably 10-20 mm, and most preferably about 15 mm.
Because the purpose of the cover 12 is to form an air-flow passage, it could be made of any material, but from the standpoints of ease of manufacture, weight and cost, synthetic resin is preferable. Such synthetic resin could be transparent or colored. The synthetic resin, however, must have the strength to endure the passage of the air flow as well as the load of a ventilator fan described below.
As shown in FIG. 4, the cover is usually a unit consisting of from two to six elements, and each element is provided with an opening 16 for housing a support and another opening (blocked by a fan and not visible in FIG. 4) for housing the ventilator fan described below. The two to six cover elements could be completely joined with each other with their end surfaces in contact with each other, but for the ease of repair or replacement of the actuator or cleaning of the cylindrical chamber, the end surfaces of the cover elements are preferably positioned slightly disaligned from each other inward or outward, and a rail is provided at the lower end of the cover so that the cover elements can slide.
In order to feed the outside air into the cylindrical chamber 13 through the opening on the side wall of the cover, at least one ventilator fan 17 is attached thereto.
For the ventilator fan 17 , a propeller fan, for example, by Oriental Motor K.K., Taiko-ku, Tokyo, (model number: MU1238A-11B) can be used. The number of fans can vary according to the size of the circular knitting machine, but for a circular knitting machine of a diameter of 30 inches, from 1 to 10, preferably from 3 to 8 and most preferably 5 or 6 fans are used. Each ventilator fan 17 is preferably provided with a filter (not shown) at the suction inlet of the fan.
According to this configuration, as indicated by the arrows in FIG. 1, the outside air is drawn into the cylindrical chamber 13 by the ventilator fan 17 , and runs through the gap 15 and the opening 14 , and upwards along the cylinder cam holder 6 , cooling the parts along the way.
FIGS. 5 and 6 show two modified forms of the inverted L-shaped cover top 12 a. In the modified form shown in FIG. 5, the tip of the cover is provided with a shutter 20 that closes or opens the opening 14 via a hinge 22 . The hinge 22 can be made of any material as long as it is light enough to be opened or closed by air pressure. While the knitting machine is in operation, the shutter 20 is lifted upwards by the air running towards the core knitting section, so it does not block the air passage. On the other hand, when the knitting machine is out of operation for the purpose of cleaning the knitting machine using an air gun 19 , the opening 14 is closed by the weight of the shutter 20 itself and the pressure of the air, thus preventing the intrusion of cotton dust.
In the modified form shown in FIG. 6, a filter 21 covering the entire area of the opening 14 is established at the tip of the cover top 12 a. The filter can be made, for example, of a net equipped with meshes of a size capable of preventing the intrusion of cotton dust. While the knitting machine is in operation, the air running towards the core knitting section passes the net freely, so the net does not block the air passage. On the other hand, when the knitting machine is out of operation for the purpose of cleaning the knitting machine using the air gun 19 , the filter prevents the intrusion of cotton dust.
FIG. 2 is a cross sectional view of the knitting section of a knitting machine according to the second embodiment of the present invention. The parts that are functionally equivalent to those used in the first embodiment are given the same numbers, and their detailed explanations are not repeated.
The second embodiment is different from the first embodiment in respect of the following points:
1. The cover 12 is mounted so as to almost completely seal the space between the intermediate ring 7 and the lower ring 9 .
2. Air holes (openings) 18 are formed so as to penetrate the intermediate ring 7 as well as a cylinder-cam-holder mount 6 a which is used to mount the cylinder cam holder 6 onto the intermediate ring 7 .
The number of air holes 18 can vary according to the size of the circular knitting machine, but for a circular knitting machine of a diameter of 30 inches, such number can be 10-100, but is preferably 30-80 and most preferably 50-60. The size of each air hole is preferably 5-20 mm, more preferably 8-15 mm and most preferably about 10 mm.
EFFECTS OF THE INVENTION
Using a double-knit circular knitting machine equipped with a knitting-tool-controlling apparatus (JP-A-9-21042 (1997)) by the present applicant, the temperatures of various parts of the knitting section were measured in order to compare operating results where the knitting machine is equipped with the apparatus of the present invention with operating results where the knitting machine is not equipped therewith.
The common knitting conditions were as follows:
Diameter of the knitting machine: 30 inches
Rotational frequency of the knitting machine: 23 rpm
Knit fabric: Interlock
Yarn: Polyester 75 denier
The different knitting conditions were as follows:
Prior Art 1
A sealed-type cover was installed. Because no ventilator fan was installed, there was no air flow into the inside of the cover. When the machine was run approximately 6,000 cycles under the above conditions, the temperature measurement exceeded 80° C., when the measurement was stopped.
Prior Art 2
A sealed-type cover and a fan were installed. This configuration is similar to JP-A-10-60759 (1998) referred to in the description of the prior art. In this configuration, the machine was run 10,000 cycles, and temperatures were taken when they stabilized.
The Present Invention
In the configuration described in the first embodiment (i.e., the size of the opening and gap were 15 mm each, and the number of fans was 6), the machine was run 10,000 cycles, and temperatures were taken when they stabilized.
Results
The results are shown in Table 1 below.
TABLE 1
Unit: ° C.
Prior Art 1
Prior Art 2
First Embodiment
(6) Cylinder cam holder
76
73
59
(7) Intermediate ring
58
49
48
(5) Actuator
83
51
50
(13) Inside cover (cylindrical
63
34
41
chamber)
(2) Needle cylinder
89
—
60
Room temperature (3 m away
23
20
26
from the knitting machine)
Observation
The reason that the needle cylinder measured the highest temperatures is that when the knitting machine runs at high speed, friction occurs between the knitting tools (knitting needles, jacks, etc.) and the needle cylinder. Using the apparatus of the first embodiment of the present invention lowered the temperature (of the needle cylinder) when compared to Prior Art 1 by 29° C. The cylinder temperature of Prior Art 2 was not measured.
In Prior Art 1, the actuator generated the second highest temperature. The reason is that when knitting an interlock knit fabric as used in this test, the power consumption of the actuator is fairly large. Using the apparatus of the first embodiment of this invention, however, lowered the temperature of the actuator by 33° C. compared with Prior Art 1. Prior Art 2 resulted in a temperature 32° C. lower compared with Prior Art 1.
Heat from the intermediate ring is caused by thermal conduction from other parts as well as by the friction with the cams, etc., that are fastened to the intermediate ring. Using the apparatus of the first embodiment lowered the temperature of this part by 10° C. compared with Prior Art 1. Prior Art 2 resulted in a temperature 9° C. lower compared with Prior Art 1.
Except for the needle cylinder, for which the temperature was not measured for Prior Art 2, the present invention and Prior Art 2 did not produce significant differences in respect of the temperatures of the actuators and of the intermediate rings. The difference between the present invention and the prior arts was most significant in the case of the cylinder cam holder.
Heat from the cylinder cam holder is caused by the heat generated by the needle cylinder as well as by the friction with the cylinder cams, etc., that are fastened to the cylinder cam holder. While the apparatus of the first embodiment lowered the temperature of this section by 17° C., Prior Art 2 only lowered it by 3° C.
The temperature inside the cover of Prior Art 2 (34° C.) is lower than that of the first embodiment of the present invention (41° C.) by 7° C. It is believed that because the air of the test room was fed into the chamber inside the cover using a fan, the difference in the room temperatures in the case of the first embodiment (26° C.) and in the case of Prior Art 2 (20° C.) was directly reflected in the temperatures inside the cover. The difference between the room temperature and the temperature of the air inside the cover is about the same in each of these cases.
According to the above observation, the present invention is capable of efficiently cooling the needle cylinder and its peripheral parts using a relatively simple configuration. Even when compared with the closest prior art, the present invention produces an excellent result in respect of the cooling of the needle cam holder.
As a supplemental advantage of the present invention, the air flowing out of the opening is effective in blowing away the lint floating in the knitting section, thereby reducing its adherence to the knitting yarn and the resulting occurrences of defective fabrics and lowering of the operation rate of the knitting machine.
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A needle-selecting actuator ( 5 ) is surrounded by an intermediate ring ( 7 ) at the top, a lower ring ( 9 ) at the bottom, a needle cylinder ( 2 ) inside, and a cover ( 12 ) outside. A cylindrical chamber ( 13 ) is formed between the needle-selecting actuator ( 5 ) and the cover ( 12 ). The cover ( 12 ) is equipped with a ventilator fan ( 17 ) for feeding the air into the cylindrical chamber ( 13 ). The cylindrical chamber ( 13 ) has an opening ( 14, 15; 18 ) through which the air passes. The outside air is fed into the cylindrical chamber ( 13 ) through the means of ventilation/suction ( 17 ), and passes through said opening ( 14, 15; 18 ) to cool the needle cylinder ( 2 ) and its peripheral working components.
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CROSS REFERENCE OF RELATED APPLICATION
This application is a continuation of application Ser. No. 11/408,963, filed Apr. 24, 2006, now U.S. Pat. No. 7,379,841. The disclosure of Japanese Patent Application No. 2006-79485 is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an inclination calculation apparatus and an inclination calculation program, and more specifically to an inclination calculation apparatus and an inclination calculation program for calculating an inclination of an input device using an output from an acceleration detection device included in the input device.
2. Description of the Background Art
Conventionally, technologies for calculating an inclination of a device including acceleration detection means have been proposed. For example, patent document 1 (Japanese Laid-Open Patent Publication No. 2001-159951) describes an information processing device including acceleration detection means. In this information processing device, an inclination of the device is calculated from an acceleration detected by the acceleration detection means (an angle of the device with respect to a direction of gravity), and an operation command is generated using the calculated inclination.
This information processing device has a built-in two-axial acceleration sensor. The inclination angle of the device is calculated from a component of the acceleration which is detected in two axial directions when the device is inclined. If the detected acceleration represents only an acceleration of gravity, the inclination of the device can be accurately calculated from the detected acceleration. However, the detected acceleration possibly includes an acceleration of a noise component provided by vibration of the hand of a user or the like in addition to the acceleration of gravity. Therefore, the device described in the above-mentioned publication executes processing of extracting a low-frequency component of the detected acceleration; for example, the device calculates a time average of the detected acceleration. In addition, this information processing device assumes that a change in the acceleration caused by a motion of a human being is smooth and slow. When the low-frequency component does not change during a predetermined pause period, the device determines that the user has performed some operation on the device and processes to change a value to be output as an inclination of the device (inclination operation information). By such processing, the acceleration of the noise component is eliminated from the acceleration detected by the acceleration detection means (acceleration sensor), and thus the inclination of the device can be calculated.
According to the technology described in patent document 1, the device executes the processing of calculating a time average and the processing of determining whether or not the detected acceleration has changed during a predetermined pause period, in order to calculate the inclination of the device. Such processing causes a delay in providing the inclination operation information. In other words, the above-described technology is not capable of calculating the inclination of the device in real time from the detected value of the acceleration. Also according to the technology described in patent document 1, characteristic information to be used for the above-mentioned processing for generating the inclination operation information needs to be prepared in accordance with the type of the operation. Therefore, the contents of the processing needs to be changed in accordance with the characteristic information. This restricts the range of applicable operations and complicates the processing
SUMMARY OF THE INVENTION
Therefore, at least one aspect of the non-limiting illustrative exemplary implementation disclosed herein is to provide an inclination calculation apparatus and an inclination calculation program capable of computing an inclination of a device in real time using an acceleration detected an acceleration detector sensor.
Reference numerals, additional explanations and the like shown within parentheses in this section of the specification indicate correspondence with elements within the Figures illustrating the non-limiting example implementations described herein.
In a First non-limiting aspect, applicant's illustrative example implementation disclosed herein is directed to an inclination calculation apparatus (game apparatus 3 ) for computing an inclination of an input device (controller 7 ) which includes an acceleration detector(acceleration sensor 37 ) that is capable of repeatedly detecting an acceleration in at least two axial directions. The inclination calculation apparatus comprises preliminary data generation means (CPU 10 , etc. for executing step S 13 or S 29 ; hereinafter, only the corresponding step numbers will be mentioned) and inclination calculation means (S 17 and S 18 , or S 33 and S 34 ). The preliminary data generation means sequentially generates preliminary data ( 531 ) which represents an inclination and is uniquely determined from acceleration data ( 521 ) output from the acceleration detection means. The inclination calculation means sequentially calculates a new inclination (i.e., repeatedly computes corresponding new/updated inclination values) by making an inclination previously calculated closer to an inclination represented by the preliminary data at a predetermined angle/degree (effectiveness k) (i.e., by using an inclination determined by using an “effectiveness” value “k” which represents a predetermined inclination vector angle/degree between a previously computed inclination vector and a current inclination represented by the preliminary data).
In a second non-limiting aspect of applicant's illustrative example implementation disclosed herein, the preliminary data may represent an inclination of the input device under an assumption that the acceleration data represents only an acceleration of gravity.
In a third non-limiting aspect of applicant's illustrative example implementation disclosed herein, the acceleration detection means may be capable of detecting an acceleration in three axial directions (x-y-z directions) In this case, the inclination calculation means calculates an inclination in two axial directions (x-y directions) among the three axial directions. The preliminary data generation means generates preliminary data representing an inclination in two axial directions, corresponding to the inclination calculated by the inclination calculation means, from the acceleration data representing the acceleration in the three axial directions.
In a fourth non-limiting aspect of applicant's illustrative example implementation disclosed herein, the Inclination calculation apparatus may further comprise magnitude calculation means (S 11 or S 21 ) for calculating a magnitude of the acceleration represented by the acceleration data. In this case, the inclination calculation means sequentially varies the degree in accordance with the magnitude of the acceleration, such that the degree is greater as the magnitude of the acceleration calculated by the magnitude calculation means is closer to a magnitude of the acceleration of gravity.
In a fifth non-limiting aspect of applicant's illustrative example implementation disclosed herein, the inclination calculation apparatus may further comprise magnitude calculation means (S 11 or S 21 ) for calculating a magnitude of the acceleration represented by the acceleration data. In this case, the inclination calculation means calculates an inclination only when a difference between the magnitude of the acceleration calculated by the magnitude calculation means and a magnitude of the acceleration of gravity is equal to or less than a predetermined threshold value.
In another non-limiting aspect, applicant's illustrative example implementation disclosed herein may be provided in the form of a computer-readable storage medium having stored thereon an inclination calculation program for causing a computer of an inclination calculation apparatus to execute the above-described invention. The present invention may be provided in the form of a game apparatus using an inclination calculated by the above invention as an operation input for a game, or in the form of a computer-readable storage medium having stored thereon a game program for causing a computer of the game apparatus to execute the above-described invention.
According to the first aspect, an inclination of the input device is calculated based on an inclination determined from the acceleration data and an inclination calculated previously, instead of regarding an inclination determined from the acceleration data as the inclination of the input device. Thus, even when the acceleration rapidly changes as a result of an influence of components other than the acceleration of gravity being added to the output from the acceleration detection means, the influence can be alleviated. Therefore, according to the first aspect, a reasonably accurate inclination can be obtained constantly. In addition, since the information used for calculating an inclination of the input device is an inclination determined from the acceleration data and an inclination calculated previously, the inclination of the input device can be calculated in real time.
According to the second aspect, a preliminary vector can be easily obtained from the output of the acceleration detection means.
According to the third aspect, an inclination in two axial directions from an acceleration in three axial directions detected by the acceleration detection means.
According to the fourth aspect, the inclination calculation means varies a predetermined degree in accordance with the closeness between the magnitude of the acceleration detected by the acceleration detection means and the magnitude of the acceleration of gravity. Thus, when the detected acceleration is significantly influenced by components other than the acceleration of gravity, i.e., when the inclination represented by the generated data is determined to be significantly offset from the accurate inclination, the inclination calculated by the inclination calculation means is close to the inclination calculated previously. By contrast, when the detected acceleration is not much influenced by components other than the acceleration of gravity, i.e., when the inclination represented by the generated data is determined to be close to the accurate inclination, the inclination calculated by the inclination calculation means is close to the inclination represented by the generated data. Thus, the degree at which the generated data influences the inclination calculated by the inclination calculation means can be varied in accordance with the determination result on whether or not the inclination represented by the generated data is close to the accurate inclination (inclination to be calculated). Therefore, the inclination of the input device can be more accurately calculated.
According to the fifth aspect, when the difference between the magnitude of the acceleration detected by the acceleration detection means and the magnitude of the acceleration of gravity is equal to or greater than a threshold value, the inclination is not calculated using the generated data and the inclination calculated previously. In the above case, the acceleration detected by the acceleration detection means includes many components other than the acceleration of gravity. Therefore, it is difficult to accurately calculate the inclination. According to the fifth aspect, the inclination is not calculated in such a case. Thus, an inaccurate inclination can be prevented from being calculated.
These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an external view of a game system including a game apparatus 3 as an exemplary inclination calculation apparatus according to one embodiment of the present invention;
FIG. 2 is a functional block diagram of the game apparatus 3 ;
FIG. 3A is an isometric view of a controller 7 ;
FIG. 3B is another isometric view of the controller 7 ;
FIG. 4 is a front view of the controller 7 ;
FIG. 5A is a view illustrating an internal structure of the controller 7 ;
FIG. 5B is another view illustrating the internal structure of the controller 7 ;
FIG. 6 is a block diagram illustrating a structure of the controller 7 ;
FIG. 7 is a view illustrating the relationship between the inclination of the controller 7 and the output from an acceleration sensor;
FIG. 8 is another view illustrating the relationship between the inclination of the controller 7 and the output from the acceleration sensor;
FIG. 9 shows a general view of a game operation using the controller 7 ;
FIG. 10 illustrates an inclination calculation processing;
FIG. 11 shows the controller 7 in a still state;
FIG. 12 shows the controller 7 in the middle of being rotated counterclockwise from the state shown in FIG. 11 ;
FIG. 13 shows main data stored on a main memory 13 of the game apparatus 3 in a first embodiment of the present invention;
FIG. 14 is a flowchart illustrating game processing executed by the game apparatus 3 ;
FIG. 15 is a flowchart illustrating a detailed flow of inclination calculation processing in step S 3 shown in FIG. 14 in the first embodiment;
FIG. 16 shows main data stored on the main memory 13 of the game apparatus 3 in a second embodiment of the present invention;
FIG. 17 is a flowchart illustrating a detailed flow of the inclination calculation processing executed in the second embodiment; and
FIG. 18 is a flowchart illustrating a detailed flow of the inclination calculation processing executed in the second embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Embodiment
With reference to FIG. 1 , a game system 1 including a game apparatus as an example of an inclination calculation apparatus according to a first embodiment of the present invention will be described. FIG. 1 is an external view illustrating the game system 1 . In the following exemplary description, the game apparatus according to the present invention is of an installation type.
As shown in FIG. 1 , the game system 1 includes an installation type game apparatus (hereinafter, referred to simply as a “game apparatus”) 3 , which is connected to a display (hereinafter, referred to as a “monitor”) 2 such as a home-use TV receiver including a speaker via a connection cord, and a controller 7 for giving operation data to the game apparatus 3 . Two markers 8 a and 8 b are provided in the vicinity of the monitor 2 (above the screen of the monitor 2 in FIG. 1 ). The markers 8 a and 8 b are specifically infrared LEDs, and each outputs infrared light forward from the monitor 2 . The game apparatus 3 is connected to a receiving unit 6 via a connection terminal. The receiving unit 6 receives operation data which is wirelessly transmitted from the controller 7 . The controller 7 and the game apparatus 3 are connected to each other by wireless communication. On the game apparatus 3 , an optical disc 4 as an example of an exchangeable information storage medium is detachably mounted. The game apparatus 3 has, on a top main surface thereof, a power ON/OFF switch, a game processing reset switch, and an OPEN switch for opening a top lid of the game apparatus 3 . When a player presses the OPEN switch, the lid is opened, so that the optical disc 4 is mounted or dismounted.
On the game apparatus 3 , an external memory card 5 is detachably mounted when necessary. The external memory card 5 has a backup memory or the like mounted thereon for fixedly storing saved data or the like. The game apparatus 3 executes a game program or the like stored on the optical disc 4 and displays the result on the monitor 2 as a game image. The game apparatus 3 can also reproduce a state of a game played in the past using saved data stored on the memory card 5 and display the game image on the monitor 2 The player playing with the game apparatus 3 can enjoy the game by operating the controller 7 while watching the game image displayed on the display screen of the monitor 2 .
The controller 7 wirelessly transmits operation data from a communication section 36 included therein (described later) to the game apparatus 3 connected to the receiving unit 6 , using the technology of, for example, Bluetooth (registered trademark). The controller 7 is operation means for operating an operation target (an object displayed on the display screen of the monitor 2 ). The controller 7 includes an operation section having a plurality of operation buttons. As described later in detail, the controller 7 also includes an acceleration sensor 37 (described later) for detecting an acceleration in at least two axial directions perpendicular to each other. Data representing an acceleration detected by the acceleration sensor 37 is transmitted to the game apparatus 3 as a part of the operation data. The game apparatus 3 performs a predetermined calculation on data representing the acceleration to calculate an inclination of the controller 7 and executes processing in accordance with the inclination when necessary. The controller 7 further includes an imaging information calculation section 35 (described later) for taking an image seen from the controller 7 . The imaging information calculation section 35 takes an image of each of the markers 8 a and 8 b located in the vicinity of the monitor 2 . The game apparatus 3 executes processing in accordance with the position and the posture of the controller 7 by calculation processing based on the image.
With reference to FIG. 2 , a structure of the game apparatus 3 will be described. FIG. 2 is a functional block diagram of the game apparatus 3 .
As shown in FIG. 2 , the game apparatus 3 includes, for example, a RISC CPU (central processing unit) 10 for executing various types of programs. The CPU 10 executes a start program stored in a boot ROM (not shown) to, for example, initialize memories including a main memory 13 , and then executes a game program stored on the optical disc 4 to perform game processing or the like in accordance with the game program The CPU 10 is connected to a GPU (Graphics Processing Unit) 12 , the main memory 13 , a DSP (Digital Signal Processor) 14 , and an ARAM (Audio RAM) 15 via a memory controller 11 . The memory controller 11 is connected to a controller I/F (interface) 16 , a video I/F 17 , an external memory I/F 18 , an audio I/F 19 , and a disc I/F 21 via a predetermined bus. The controller I/F 16 , the video I/F 17 , the external memory I/F 18 , the audio I/F 19 and the disc I/F 21 are respectively connected to the receiving unit 6 , the monitor 2 , the external memory card 5 , a speaker 22 and a disc drive 20 .
The CPU 12 performs image processing based on an instruction from the CPU 10 . The CPU 12 includes, for example, a semiconductor chip for performing calculation processing necessary for displaying 3D graphics. The CPU 12 performs the image processing using a memory dedicated for image processing (not shown) and a part of the storage area of the main memory 13 . The CPU 12 generates game image data and a movie to be displayed on the display screen of the monitor 2 using such memories, and outputs the generated data or movie to the monitor 2 via the memory controller 11 and the video I/F 17 as necessary.
The main memory 13 is a storage area used by the CPU 10 , and stores a game program or the like necessary for processing performed by the CPU 10 as necessary. For example, the main memory 13 stores a game program read from the optical disc 4 by the CPU 10 , various types of data or the like. The game program, the various types of data or the like stored in the main memory 13 are executed by the CPU 10 .
The DSP 14 processes sound data or the like generated by the CPU 10 during the execution of the game program. The DSP 14 is connected to the ARAM 15 for storing the sound data or the like. The ARAM 15 is used when the DSP 14 performs predetermined processing (for example, storage of the game program or sound data already read). The DSP 14 reads the sound data stored in the ARAM 15 and outputs the sound data to the speaker 22 included in the monitor 2 via the memory controller 11 and the audio I/F 19 .
The memory controller 11 comprehensively controls data transfer, and is connected to the various I/Fs described above. The controller I/F 16 includes, for example, four controller I/Fs, and communicably connects the game apparatus 3 to an external device which is engageable via connectors of the controller I/Fs. For example, the receiving unit 6 is engaged with such a connector and is connected to the game apparatus 3 via the controller I/F 16 . As described above, the receiving unit 6 receives the operation data from the controller 7 and outputs the operation data to the CPU 10 via the controller I/F 16 . In other embodiments, the game apparatus 3 may include a receiving module for receiving the operation data transmitted from the controller 7 , instead of the receiving unit 6 . In this case, the operation data received by the receiving module is output to the CPU 10 via a predetermined bus. The video I/F 17 is connected to the monitor 2 . The external memory I/F 18 is connected to the external memory card 5 and is accessible to a backup memory or the like provided in the external card 5 . The audio I/F 19 is connected to the speaker 22 built in the monitor 2 , and is connected such that the sound data read by the DSP 14 from the ARAM 15 or sound data directly output from the disc drive 20 is output from the speaker 22 . The disc I/F 21 is connected to the disc drive 20 . The disc drive 20 reads data stored at a predetermined reading position of the optical disc 4 and outputs the data to a bus of the game apparatus 3 or the audio I/F 19 .
With reference to FIG. 3A through FIG. 8 , the controller 7 will be described. FIG. 3A through FIG. 5B are external isometric views of the controller 7 . FIG. 3A is an isometric view of the controller 7 seen from the top rear side thereof. FIG. 3B is an isometric view of the controller 7 seen from the bottom rear side thereof. FIG. 4 is a front view of the controller 7 .
As shown in FIG. 3A , FIG. 3B and FIG. 4 , the controller 7 includes a housing 31 formed by plastic molding or the like. The housing 31 has a generally parallelepiped shape extending in a longitudinal or front-rear direction (the Z-axis direction shown in FIG. 3A ). The overall size of the housing 31 is small enough to be held by one hand of an adult or even a child. The player can use the controller 7 to perform a game operation of pressing buttons provided thereon, a game operation of changing the inclination of the controller 7 itself (the angle of the controller 7 with respect to a direction of gravity), and a game operation of changing the position or direction of the controller 7 itself. For example, the player can change the inclination of the controller 7 to move an operation target (object) appearing in the game space. Also for example, the player can rotate the controller 7 with the longitudinal direction thereof as an axis to move the operation target through processing of the linear acceleration signals generated by the acceleration sensor 37 . The player can change the position indicated by the controller 7 on the display screen to move the object appearing in the game space. The “position indicated by the controller 7 on the display screen” is ideally a position at which a phantom straight line extending from a front end of the controller 7 in the longitudinal direction crosses the display screen of the monitor 2 . However, it is not necessary that the “position indicated by the controller 7 on the display screen” is strictly such a position. It is sufficient that the game apparatus 3 can calculate a position in the vicinity thereof. Hereinafter, a position indicated by the controller 7 on the display screen will be referred to as an “indicated position” or an “indicated position by the controller 7 ”. The longitudinal direction of the controller 7 (housing 31 ) will be sometimes referred to as an “indicated direction”.
The housing 31 has a plurality of operation buttons. Provided on a top surface of the housing 31 are a cross key 32 a , an X button 32 b , a Y button 32 c , a B button 32 d , a select switch 32 e , a menu switch 32 f , and a start switch 32 g . On a bottom surface of the housing 31 , a recessed portion is formed. On a rear slope surface of the recessed portion, an A button 32 i is provided. These buttons and switches are assigned various functions in accordance with the game program executed by the game apparatus 3 , but this will not be described in detail because the functions are not directly relevant to the present invention. On the top surface of the housing 31 , a power switch 32 h is provided for remotely turning on or off the game apparatus 3 .
The controller 7 has the imaging information calculation section 35 ( FIG. 5B ). As shown in FIG. 4 , a light incident opening 35 a of the imaging information calculation section 35 is provided on a front surface of the housing 31 . On a rear surface of the housing 31 , a connector 33 is provided. The connector 33 is, for example, a 32-pin edge connector, and is used for connecting the controller 7 to another device. In a rear part of the top surface of the housing 31 , a plurality of LEDs 34 are provided. The controller 7 is assigned a controller type (number) so as to be distinguishable from the other controllers 7 . The LEDs 34 are used for informing the player of the controller type which is currently set to controller 7 that he/she is using. Specifically, when the controller 7 transmits the operation data to the game apparatus 3 , one of the plurality of LEDs 34 corresponding to the controller type is lit up.
With reference to FIG. 5A , FIG. 5B and FIG. 6 , an internal structure of the controller 7 will be described. FIG. 5A and FIG. 5B illustrate an internal structure of the controller 7 . FIG. 5A is an isometric view illustrating a state where an upper casing (a part of the housing 31 ) of the controller 7 is removed. FIG. 5B is an isometric view illustrating a state where a lower casing (a part of the housing 31 ) of the controller 7 is removed. FIG. 5B shows a reverse side of a substrate 300 shown in FIG. 5A .
As shown in FIG. 5A , the substrate 300 is fixed inside the housing 31 . On a top main surface of the substrate 300 , the operation buttons 32 a through 32 h , the acceleration sensor 37 , the LEDs 34 , a quartz oscillator 46 , a wireless module 44 , an antenna 45 and the like are provided. These elements are connected to a microcomputer 42 (see FIG. 6 ) via lines (not shown) formed on the substrate 300 and the like. The wireless module 44 and the antenna 45 allow the controller 7 to act as a wireless controller. The quartz oscillator 46 generates a reference clock of the microcomputer 42 described later.
As shown in FIG. 5B , at a front edge of a bottom main surface of the substrate 300 , the imaging information calculation section 35 is provided. The imaging information calculation section 35 includes an infrared filter 38 , a lens 39 , an imaging element 40 and an image processing circuit 41 located in this order from the front surface of the controller 7 . These elements are attached to the bottom main surface of the substrate 300 . At a rear edge of the bottom main surface of the substrate 300 , the connector 33 is attached. The operation button 32 i is attached on the bottom main surface of the substrate 300 rearward to the imaging information calculation section 35 , and cells 47 are accommodated rearward to the operation button 32 i . On the bottom main surface of the substrate 300 between the cells 47 and the connector 33 , a vibrator 48 is attached. The vibrator 48 may be, for example, a vibration motor or a solenoid. The controller 7 is vibrated by an actuation of the vibrator 48 , and the vibration is conveyed to the player holding the controller 7 . Thus, a so-called vibration-responsive game is realized.
FIG. 6 is a block diagram showing the structure of the controller 7 . The controller 7 includes the acceleration sensor 37 mentioned above. The acceleration sensor 37 detects an acceleration of the controller 7 (including an acceleration of gravity). Namely, the acceleration sensor 37 detects a force applied to the controller 7 (including gravity) and outputs the detected force as an acceleration. FIG. 7 and FIG. 8 show the relationship between the inclination of the controller 7 and the output of the acceleration sensor 37 . As shown in FIG. 7 and FIG. 8 , the acceleration sensor 37 detects an acceleration in each of three axial directions regarding the controller 7 , i.e., the up-down direction (y-axis direction in FIG. 7 ), the left-right direction (x-axis direction in FIG. 7 ), and the front-rear direction (the z-axis direction in FIG. 7 ). Namely, the acceleration sensor 37 detects an acceleration in a linear direction along an axis, and therefore an output from the acceleration 37 represents an a value of an acceleration in each axis. Therefore, the detected acceleration is represented as a three-dimensional vector in an x-y-z coordinate system (see FIG. 7 and FIG. 8 ) which is set based on the controller 7 . Herein, the upward direction regarding the controller 7 is set as a positive y-axis direction, the frontward direction regarding the controller 7 is set as a positive z-axis direction, and the leftward direction regarding the controller 7 in the case where the controller 7 is viewed from the rear end thereof toward the front end thereof is set as a positive x-axis direction.
As explained above, the controller 7 preferably includes a three-axis, linear acceleration sensor 37 that detects linear acceleration in each of the three axial directions described above. Alternatively, a two axis linear accelerometer that only detects linear acceleration along each of the X-axis and Y-axis (or other pair of axes) may be used in another embodiment depending on the type of control signals desired. As a non-limiting example, the three-axis or two-axis linear accelerometer 37 may be of the type available from Analog Devices, Inc. or STMicroelectronics W.V. Preferably, the acceleration sensor 37 is an electrostatic capacitance or capacitance-coupling type that is based on silicon micro-machined MEMS(microelectromechanical systems) technology. However, any other suitable accelerometer technology (e.g., piezoelectric type or piezoresistance type) now existing or later developed may be used to provide the three-axis or two-axis acceleration sensor 37 .
As one skilled in the art understands, linear 25 accelerometers, as used in acceleration sensor 37 , are only capable of detecting acceleration along a straight line corresponding to each axis of the acceleration sensor. In other words, the direct output of the acceleration sensor 37 is limited to signals indicative of linear acceleration (static or dynamic) along each of the two or three axes thereof. As a result, the acceleration sensor 37 cannot directly detect movement along a non-linear (e.g. arcuate) path, rotation, rotational movement, angular displacement, tilt, position, attitude or any other physical characteristic.
However, through additional processing of the linear acceleration signals output from the acceleration sensor 37 , additional information relating to the controller 7 can be inferred or calculated, as one skilled in the art will readily understand from the description herein. For example, by detecting static, linear acceleration (i.e., gravity), the linear acceleration output of the acceleration sensor 37 can be used to infer or calculate tilt or inclination of the object relative to the gravity vector by correlating tilt angles with detected linear acceleration. In this way, the acceleration sensor 37 can be used in combination with the micro-computer 42 (or another processor) to determine tilt, attitude or position of the controller 7 . Similarly, various movements and/or positions of the controller 7 can be calculated or inferred through processing of the linear acceleration signals generated by the acceleration sensor 37 when the controller 7 containing the acceleration sensor 37 is subjected to dynamic accelerations by, for example, the hand of a user. In another embodiment, the acceleration sensor 37 may include an embedded signal processor or other type of dedicated processor for performing any desired processing of the acceleration signals output from the accelerometers therein prior to outputting signals to microcomputer 42 . For example, the embedded or dedicated processor could convert the detected acceleration signal to a corresponding tilt angle when the acceleration sensor is intended to detect static acceleration (i.e., gravity).
FIG. 7 shows a state where an acceleration of gravity (vector Va in FIG. 7 ) is directed downward regarding the controller 7 . In this state, the value Va of an acceleration detected by the acceleration sensor 37 (hereinafter, referred to as an “acceleration vector”) is in a negative y-axis direction. In FIG. 7 and FIG. 8 , it is assumed that the controller 7 is in a still state. In the state shown in FIG. 7 , only the y coordinate value of the acceleration vector Va is not zero, and both the x coordinate value and the z coordinate value of the acceleration vector Va are zero. FIG. 8 shows a state in which the controller 7 is inclined as a result of being rotated from the state shown in FIG. 7 around the z axis. In the state shown in FIG. 8 , the direction of the acceleration vector Va is changed from the state in FIG. 7 . The x coordinate value and the y coordinate value of the acceleration vector Va are not zero, and the z coordinate value of the acceleration vector Va is zero because the controller 7 has been rotated around the z axis. As shown in FIG. 7 and FIG. 8 , the acceleration sensor 37 can detect a value of an acceleration having three axial directions regarding the controller 7 as components. Thus, a calculation handling the value of the acceleration as an acceleration vector having the three axial components is performed by software processing using a computer such as the microcomputer 42 or the CPU 10 , and thus an inclination of the controller 7 can be calculated. Data representing the acceleration detected by the acceleration sensor 37 (acceleration data) is output to the communication section 36 . In the first embodiment, the acceleration sensor 37 outputs a value in accordance with the acceleration sequentially (specifically, frame by frame). The game apparatus 3 performs a predetermined calculation handling the value as an acceleration vector to calculate the inclination (posture) of the controller 7 , and executes game processing in accordance with the inclination.
In this embodiment, the magnitude of an acceleration which is detected when the controller 7 is in a still state, i.e., the magnitude of an acceleration which represents only an acceleration of gravity, is set as 1. For example, the values of the components of the acceleration vector Va detected in the state shown in FIG. 7 are (0, 1, 0).
In the first embodiment, it is intended to calculate an inclination of the controller 7 in the x-y directions. Therefore, in the first embodiment, an acceleration sensor for detecting an acceleration in only two axial directions (x-y directions) may be used instead of the acceleration sensor 37 for detecting an acceleration in three axial directions. The acceleration sensor 37 is typically of a static capacitance type, but may be of any other system.
The controller 7 includes the operation section 32 (operation buttons), the imaging information calculation section 35 , and the communication section 36 in addition to the acceleration sensor 37 . In this embodiment, the controller 7 only needs to include acceleration detection means (the acceleration sensor 37 ) and may not absolutely need to include the operation section 32 or the imaging information calculation section 35 .
Returning to FIG. 6 , the imaging information calculation section 35 is a system for analyzing image data taken by imaging means and detecting the position of the center of gravity, the size and the like of an area having a high brightness in the image data. The imaging information calculation section 35 has, for example, a maximum sampling period of about 200 frames/sec., and therefore can trace and analyze even a relatively fast motion of the controller 7 .
Specifically, the imaging information calculation section 35 includes the infrared filter 38 , the lens 39 , the imaging element 40 and the image processing circuit 41 . The infrared filter 38 allows only infrared light to pass therethrough, among light incident on the front surface of the controller 7 . The markers 8 a and 8 b located in the vicinity of the display screen of the monitor 2 are infrared LEDs for outputting infrared light forward from the monitor 2 . Therefore, the provision of the infrared filter 38 allows the image of each of the markers 8 a and 8 b to be taken more accurately. The lens 39 collects the infrared light which has passed through the infrared filter 38 and outputs the infrared light to the imaging element 40 . The imaging element 40 is a solid-state imaging device such as, for example, a CMOS sensor or a CCD. The imaging element 40 takes an image of the infrared light collected by the lens 39 . Accordingly, the imaging element 40 takes an image of only the infrared light which has passed through the infrared filter 38 and generates image data. Hereinafter, an image taken by the imaging element 40 will be referred to as a “taken image”. The image data generated by the imaging element 40 is processed by the image processing circuit 41 . The image processing circuit 41 calculates the positions of the imaging targets (the markers 8 a and 8 b ) in the taken image. The positions are represented in a coordinate system (x′-y′ coordinate system) in which the downward direction of the taken image is a positive y′-axis direction and the rightward direction of the taken image is a positive x′-axis direction. The image processing circuit 41 outputs coordinate values indicating the respective positions of the markers 8 a and 8 b in the taken image to the communication section 36 as imaging data. Since these coordinate values vary in accordance with the direction or position of the controller 7 itself, the game apparatus 3 can calculate the direction and position of the controller 7 using these coordinate values.
The communication section 36 includes the microcomputer 42 , a memory 43 , the wireless module 44 and the antenna 45 . The microcomputer 42 controls the wireless module 44 for wirelessly transmitting the data obtained by the microcomputer 42 while using the memory 43 as a storage area during processing.
Data which is output from the operation section 32 , the acceleration sensor 37 and the imaging information calculation section 35 to the microcomputer 42 is temporarily stored in the memory 43 . The wireless transmission from the communication section 36 to the receiving unit 6 is performed at a predetermined time interval. Since game processing is generally performed at a cycle of 1/60 sec., the wireless transmission needs to be performed at a cycle of a shorter time period. At the transmission timing to the receiving unit 6 , the microcomputer 42 outputs the data stored in the memory 43 to the wireless module 44 as operation data. The wireless module 44 uses, for example, the Bluetooth (registered trademark) technology to modulate a carrier wave of a predetermined frequency with the operation data and radiate the resultant very weak electric signal from the antenna 45 . Namely, the operation data is modulated into a very weak electric signal by the wireless module 44 and transmitted from the controller 7 . The very weak electric signal is received by the receiving unit 6 on the side of the game apparatus 3 . The received very weak electric signal is demodulated or decoded, so that the game apparatus 3 can obtain the operation data. The CPU 10 of the game apparatus 3 executes the game processing based on the obtained operation data and the game program.
The shape of the controller 7 , and the shape, number, position or the like of the operation buttons and switches shown in FIG. 3A through FIG. 5B are merely exemplary, and may be altered without departing from the scope of the present invention. The position of the imaging information calculation section 35 in the controller 7 (the light incident opening 35 a of the imaging information calculation section 35 ) does not need to be on the front surface of the housing 31 , and may be on another surface as long as light can enter from the outside of the housing 31 . In this case, the “indicated direction” is a direction vertical to the light incident opening, i.e., the direction in which the imaging element 40 takes images of the imaging targets.
By using the controller 7 , the player can perform a game operation of changing the inclination of the controller 7 , of changing the position of the controller 7 itself, or of rotating the controller 7 , in addition to the conventional game operation of pressing the operation buttons or switches. Hereinafter, the game operations using the controller 7 will be described.
FIG. 9 is a general view or a game operation using the controller 7 . As shown in FIG. 9 , when playing the game using the controller 7 with the game system 1 , the player holds the controller 7 with one hand. The markers 8 a and 8 b are located parallel to the transverse or width direction of the monitor 2 . The player holds the controller 7 such that the front surface of the controller 7 (having the light incident opening 35 a by which the imaging information calculation section 35 takes the image of each of the markers 8 a and 8 b ) faces the markers 8 a and 8 b . In this state, the player performs a game operation of changing the inclination of the controller 7 , of changing the position indicated by the controller 7 on the display screen (indicated position), or of changing the distance between the controller 7 and the markers 8 a and 8 b.
Next, processing of calculating an inclination of the controller 7 using an output from the acceleration sensor 37 will be described. In a still state of controller 7 , the acceleration vector which is output from the acceleration sensor 37 is directed in the direction of the acceleration of gravity (see FIG. 7 and FIG. 8 ). Therefore, the angle of the controller 7 with respect to the direction of the acceleration of gravity, i.e., the inclination of the controller 7 , can be represented as a difference between the direction of the acceleration vector and the negative y-axis direction. Namely, in a still state of the controller 7 , the value of the acceleration vector itself can be used as the Inclination of the controller 7 . In a state where the controller 7 is moving or rotating, the acceleration vector does not match the direction of the acceleration of gravity. Therefore, the value of the acceleration vector itself cannot be used as the inclination of the controller 7 . In this embodiment, the acceleration is sequentially detected by the acceleration sensor 37 , and also the inclination of the controller 7 is sequentially calculated. The inclination of the controller 7 at the current time is calculated using the output from the acceleration sensor 37 detected at the current time and the inclination of the controller 7 calculated at the previous time.
First with reference to FIG. 10 , an overview of inclination calculation processing will be described. In the first embodiment, an inclination of the controller 7 regarding the rotation around the z axis will be calculated. FIG. 10 illustrates the inclination calculation processing. The inclination calculation processing is executed as follows. The game apparatus 3 first calculates a preliminary vector vh from the acceleration vector Va detected by the acceleration sensor 37 . The preliminary vector vh indicates an inclination of the controller 7 represented by the acceleration vector itself. Specifically, the preliminary vector vh is obtained by extracting an x-axis component and a y-axis component of the acceleration vector Va and performing predetermined coordinate set conversion on the extracted two-dimensional vector. The preliminary vector vh is represented in the x′-y′ coordinate system shown in FIG. 10 , and has the origin of the x′-y′ coordinate system as a start point. The preliminary vector vh is a unit vector having a length of 1 . The preliminary vector vh is uniquely, determined from the acceleration vector. The preliminary vector vh represents an inclination of the controller 7 under an assumption that the acceleration vector represents the acceleration of gravity (an assumption that the acceleration vector is directed in the direction of the acceleration of gravity).
The reason why only the x-axis component and the y-axis component of the acceleration vector Va are extracted is as follows. In the first embodiment, it is intended to calculate an inclination of the controller 7 regarding the rotation around the z axis (in the x-y directions), and therefore a z-axis component is not necessary. The reason why predetermined coordinate set conversion is performed on the extracted two-dimensional vector is that in the first embodiment, an inclination of the controller 7 is represented in a coordinate system different from the x-y-z coordinate system (represented in the x′-y′ coordinate system shown in FIG. 10 ). In the x′-y′ coordinate system, the positive x′-axis direction corresponds to the negative y-axis direction of the x-y-z coordinate system, and the positive y′-axis direction corresponds to the negative x-axis direction of the x-y-z coordinate system. The x′-y′ coordinate system is for representing positions of the imaging targets (the markers 8 a and 8 b ) in a taken image which are calculated by the imaging information calculation section 35 . By using the same coordinate system to process the inclination of the controller 7 calculated from the output of the acceleration sensor 37 and the positions of the imaging targets obtained from the imaging information calculation section 35 , processing of reflecting both the inclination and the positions on the game operation is facilitated in other embodiments, it is not absolutely necessary to use the images of the markers 8 a and 8 b for the game operation, in which case the above-mentioned coordinate set conversion is not necessary.
After calculating the preliminary vector vh, the game apparatus 3 calculates an inclination vector vah (see FIG. 10 ) based on the preliminary vector vh and a previous vector vbh. The inclination vector represents an inclination of the controller 7 to be calculated and is used for the game operation. The previous vector vbh is an inclination vector calculated previously. In this specification, the term “previous” means “immediately previous”. In the case where, for example, the game apparatus 3 calculates an inclination vector frame by frame, the previous vector vbh is an inclination vector calculated one frame before. Like the preliminary vector vh, the inclination vector vah and the previous vector vbh are both a unit vector having a length of 1, and have the origin of the x′-y′ coordinate system as a start point.
As shown in FIG. 10 , the inclination vector vah is obtained by making the direction of the previous vector vbh closer to the direction of the preliminary vector vh at a predetermined degree. In the following description, the predetermined degree will be represented as an effectiveness k (0≦k≦1. Specifically, the inclination vector vah is directed from the origin toward point P and has a length of 1. Point P divides a line segment connecting the end point of the previous vector vhh and the end point of the preliminary vector vh at a ratio of k: (1−k). In the first embodiment, the effectiveness k is calculated based on the length of the preliminary vector vh. A method for calculating the effectiveness k will be described in detail later.
In the state where the controller 7 is being moved or rotated by the operation of the player, acceleration components other than the acceleration of gravity are detected. Therefore, the acceleration vector itself cannot be regarded as the inclination of the controller 7 . An inclination of the controller 7 calculated only based on the acceleration vector is not accurate. With reference to FIG. 11 and FIG. 12 , this will be described.
FIG. 11 shows the controller 7 in a still state. FIG. 11 and FIG. 12 shows the controller 7 seen from the rear end thereof. In the state shown in FIG. 11 , the direction of an acceleration vector Va 1 detected by the acceleration sensor 37 matches a direction G of an acceleration of gravity. Therefore, the acceleration vector Va 1 itself can be regarded as the inclination of the controller 7 . The inclination thus calculated is accurate. FIG. 12 shows the controller 7 in the middle of being rotated counterclockwise from the state in FIG. 11 . In the state shown in FIG. 12 , an acceleration vector Va 2 which is offset clockwise (in the opposite direction to the moving direction of the controller 7 ) from the direction G of the actual acceleration of gravity is detected. As shown in FIG. 12 , the direction of the acceleration vector changes more drastically than the inclination of the controller 7 . The length of the acceleration vector Va 2 is different from the length of the acceleration vector Va 1 which matches the acceleration of gravity (in the example of FIG. 12 , the acceleration vector Va 2 is longer than the acceleration vector Va 1 ). It is considered that such changes are caused by, for example, a centrifugal force or an influence of an acceleration by the destabilization of the hand of the like). An inclination of the controller 7 calculated only based on the acceleration vector Va 2 is not accurate. As described above, in the state of the controller 7 in the middle of being moved or rotated by the player, the inclination of the controller 7 cannot be accurately calculated because the acceleration detected by the acceleration sensor 37 often includes components other than the acceleration of gravity. It may be possible to wait until the controller 7 gets still and calculate the inclination thereof using an acceleration vector obtained after the controller 7 gets still. This method, however, cannot calculate an inclination of the controller 7 in real time and thus cannot be easily applied to a game apparatus or the like which requires a quick responsiveness for operations thereof.
According to the first embodiment, the current inclination of the controller 7 is calculated using the direction of the current acceleration vector (the direction of the preliminary vector) and also the direction of the previous inclination vector (see FIG. 10 ), instead of in the direction of the current acceleration vector as the inclination of the controller 7 . With this method, even when the direction of the acceleration vector rapidly changes from the direction of the previous acceleration vector, the inclination vector is calculated such that the direction thereof is changed more slowly than the direction of the acceleration vector. In the example of FIG. 12 , the direction of the inclination vector is between the direction of the previous acceleration vector Va 1 and the preliminary vector Va 2 (for example, the inclination vector is a vector Va 3 ). With this method, an inclination vector representing an inclination closer to an actual accurate inclination of the controller 7 can be obtained as compared to the case where the direction of the acceleration vector itself (i.e., as currently detected/obtained from the acceleration sensor) is used as the inclination of the controller 7 . According to the first embodiment, the inclination of the controller 7 can be calculated more accurately.
According to the first embodiment, information used for calculating the inclination vector is the current acceleration vector and the previous inclination vector (i.e., the previous vector). Thus, according to the first embodiment, the inclination of the controller 7 can be calculated using only the information owned by the game apparatus 3 at the time when the acceleration sensor 37 obtains the acceleration vector. Therefore, the inclination of the controller 7 can be calculated in real time.
Next, game processing executed by the game apparatus 3 will be described in detail. First, main data used for the game processing will be described with reference to FIG. 13 FIG. 13 shows main data stored on the main memory 13 of the game apparatus 3 . As shown in FIG. 13 , the main memory 13 has stored thereon a game program 51 , operation data 52 , calculation processing data 53 and the like. In addition to the abovementioned data, the main memory 13 has stored thereon image data of characters appearing in the game, data representing various parameters of the characters, and other data necessary for the game processing.
The game program 51 is partially or entirely read from the optical disc 4 at an appropriate time after the game apparatus 3 is powered on and stored on the main memory 13 . The game program 51 includes an inclination calculation program 511 . The inclination calculation program 511 is a program for executing the processing of calculating an inclination of the controller 7 (the inclination calculation processing) using an output from the acceleration sensor 37 . The game program 51 includes programs necessary for the game processing in addition to the inclination calculation program 511 .
The operation data 52 is transmitted from the controller 7 to the game apparatus 3 and stored on the main memory 13 . The operation data 52 includes acceleration data 521 . The acceleration data 521 represents an acceleration vector Va detected by the acceleration sensor 37 . Herein, the acceleration data 521 represents an acceleration in each of three axial directions (x-y-z directions) shown in FIG. 7 . In addition to the acceleration data 521 , the operation data 52 includes data representing positions of the imaging targets (the markers 8 a and 8 b ) in a taken image and data representing operations performed on the buttons and switches of the operation section 32 .
The calculation processing data 53 is used for the inclination calculation processing. The calculation processing data 53 includes preliminary data 531 , inclination data 532 , previous data 533 , two-axial length data 534 , effectiveness data 535 , and first variable data 536 .
The preliminary data 531 represents a preliminary vector vh mentioned above. More specifically, the preliminary data 531 represents an inclination uniquely determined from the acceleration data 521 , i.e., an inclination of the controller 7 calculated under an assumption that the acceleration data 521 represents an acceleration of gravity. The inclination data 532 represents an inclination vector vah. The inclination data 532 is basically calculated frame by frame, but may not be calculated when the acceleration vector Va represented by the acceleration data 521 fulfills a condition described later (step S 12 ). The previous data 533 represents a previous vector vbh. When the inclination data 532 is newly calculated and thus the main memory 13 is updated, the newly calculated inclination data is stored on the main memory 13 as the updated previous data 533 to be used in the next frame for calculating an inclination vector.
The two-axial length data 534 represents a length L 1 of the acceleration vector Va represented by the acceleration data 521 in two axial directions (x-y directions) (i.e., the length of a vector having an x component and a y component of the acceleration vector Va). The length L 1 is used for, for example, calculating an effectiveness k. The effectiveness data 535 represents an effectiveness k, which indicates a degree at which the previous vector vbh is made closer to the preliminary vector vh. As described later in more detail, the effectiveness k is a variable representing a degree at which the acceleration of gravity contributes to the data of the acceleration vector (a degree at which the acceleration vector is directed in the direction of the acceleration of gravity).
The first variable data 536 represents a first variable d 1 which indicates, in the case where the magnitude of the acceleration of gravity detected by the acceleration sensor 37 is 1, how close to 1 the length L 1 of the acceleration vector is. The first variable d 1 is used for calculating the effectiveness k.
Next, the game processing executed by the game apparatus 3 will be described in detail with reference to FIG. 14 and FIG. 15 . FIG. 14 is a flowchart illustrating a flow of the game processing executed by the game apparatus 3 . When the game apparatus 3 is turned on, the CPU 10 of the game apparatus 3 executes a start program stored on the boot ROM (not shown) to initialIze each unit such as the main memory 13 . The game program stored on the optical disc 4 is read into the main memory 13 , and the CPU 10 starts the execution of the game program. The flowchart shown in FIG. 14 illustrates the game processing after the above-described processing is completed. With reference to FIG. 14 , the game processing for calculating an inclination of the controller 7 from an acceleration detected by the acceleration sensor 37 will be explained in detail, and other game processing not directly relevant to the present invention will be omitted.
First in step S 1 , a game space is constructed and displayed on the monitor 2 . The CPU 10 constructs, for example, a three-dimensional game space (or a two-dimensional game space) and locates objects appearing in the game space at predetermined initial positions. A game image representing the game space thus constructed is generated and displayed on the monitor 2 . After this, the processing loop of steps S 2 through S 6 is repeated frame by frame, and thus the game proceeds.
In step S 2 , the CPU 10 obtains operation data from the controller 7 . More specifically, the controller 7 transmits the operation data to the game apparatus 3 at a predetermined time interval (for example, frame by frame), and the CPU 10 stores the transmitted operation data on the main memory 13 . The operation data includes the acceleration data.
Next in step S 3 , the CPU 10 executes the inclination calculation program 511 to execute the inclination calculation processing. In the inclination calculation processing, an inclination of the controller 7 is calculated based on the acceleration data 521 included in the operation data 52 stored on the main memory 13 in step S 2 . Hereinafter, with reference to FIG. 15 , the inclination calculation processing will be described in detail.
FIG. 15 is a flowchart illustrating a detailed flow of the inclination calculation processing in step S 3 shown in FIG. 14 . The inclination calculation processing is executed as follows. First in step S 11 , a length L 1 regarding x and y components of the acceleration data Va is calculated. When the acceleration vector Va is (ax, ay, az), the length L 1 is calculated in accordance with the following expression.
L 1=( ax 2 +ay 2 ) 1/2
The CPU 10 stores data representing the calculated length L 1 on the main memory 13 as the two-axial length data 534 .
Next in step S 12 , it is determined whether or not the length L 1 calculated in step S 11 is within a predetermined range. The predetermined range is determined in advance, and is 0<L 1 ≦2 in this embodiment. When it is determined in step S 12 that the length L 1 is within the predetermined range, processing in step S 13 is executed. When it is determined in step S 12 that the length L 1 is not within the predetermined range, processing in steps S 13 through S 18 is skipped and the CPU 10 terminates the inclination calculation processing. Namely, when the result of the determination in step S 12 is negative, the inclination of the controller 7 is not calculated.
The processing in step S 12 is executed in order to prevent an inclination of the controller 7 from being calculated when the length L 1 calculated in step S 1 is not encompassed in a predetermined range (in this embodiment, 0<L 1 ≦2) around the magnitude of the acceleration of gravity. It is considered that the length L 1 is not encompassed in the predetermined range when the acceleration detected by the acceleration sensor 37 includes many component other than the acceleration of gravity as a result of the controller 7 being violently moved by the player or the like. In such a case, it is difficult to obtain an accurate inclination of the controller 7 from the output of the acceleration sensor 37 . Therefore, in this embodiment, an inaccurate inclination is prevented from being obtained in such a case by executing the determination processing in step S 12 .
In step S 13 , a preliminary vector vh is calculated. The preliminary vector vh can be calculated from the acceleration vector Va. The CPU 10 refers to the acceleration data 521 and the two-axial length data 534 stored on the main memory 13 to calculate components (hx, hy) of the preliminary vector vh in accordance with the following expressions.
hx=−ay/L 1
hy=−ax/L 1
In the above expressions, ax is a value of the x component of the acceleration vector Va, and ay is a value of the y component of the acceleration vector Va. The reason why −ay is used for calculating hx and −ax is used for calculating hy in the above expressions is that coordinate set conversion from the coordinate system of the acceleration vector (x-y-z coordinate system) into the coordinate system of the preliminary vector (x′-y′ coordinate system) is to be performed. The reason why −ay and −ax are each divided by the length L 1 is that the length of the preliminary length is to be 1. The CPU 10 stores data representing the calculated preliminary vector vh (=(hx, hy)) on the main memory 13 as the preliminary data 531 .
By a series of processing in steps S 14 through S 16 , a 15 first variable d 1 is calculated based on the length L 1 . In the series of processing, the first variable d 1 is calculated such that the value of the first variable d 1 is greater within the range of 0≦d 1 ≦1 as the length L 1 is closer to 1. First in step S 14 , it is determined whether or not the length L 1 is less than 1. The CPU 10 can find the value of the length L 1 by referring to the two-axial length data 534 stored on the main memory 13 . When it is determined in step S 14 that the length L 1 is less than 1, processing in step S 15 is executed. When it is determined in step S 14 that the length L 1 is equal to or greater than 1, processing in step S 16 is executed.
In step S 15 , the value of the length L 1 is set as the value of the first variable d 1 . In step S 16 , the first variable d 1 is calculated in accordance with the following expression.
d 1=2− L 1
Namely, the first variable d 1 is represented as a closeness of the length L 1 to 1. Data representing the first variable d 1 obtained in step S 15 or S 16 is stored on the main memory 13 as the first variable data 536 . After step S 15 or S 16 , processing in step S 17 is executed.
in step S 17 , an effectiveness k is calculated based on the first variable d 1 . As described above, the effectiveness k is a variable representing a degree at which the direction of the previous vector vbh is made closer to the direction of the preliminary vector vh for calculating an inclination vector vah. Specifically, the CPU 10 calculates the effectiveness k in accordance with the following expression.
k=d 12× A
In the above expression, A (>0) is a constant predetermined in the inclination calculation program 511 . Data representing constant A is stored on the main memory 13 in advance. The CPU 10 stores data representing the calculated effectiveness k on the main memory 13 as the effectiveness data 535 . As can be appreciated from the above expression, the effectiveness k is greater in the range of 0≦k≦1 as the value of the first variable d 1 is greater.
Next in step S 18 , an inclination vector vah is calculated. In this embodiment, the inclination vector vah is calculated using the preliminary vector vh, the previous vector vbh, and the effectiveness k. Specifically, the CPU 10 first calculates a vector (ahx′, ahy′) in accordance with the following expressions.
ahx′= ( hx−bhx )× k+bhx
ahy′= ( hy−bhy )× k+bhy
In the above expressions, the preliminary vector vh is (hx, hy) and the previous vector vbh is (bhx, bhy). The vector (ahx′, ahy′) calculated by the above expressions is directed in the same direction as the inclination vector vah. Next, the CPU 10 corrects the above-calculated vector into a unit vector in accordance with the following expressions, thus to calculate the inclination vector vah (=(ahx, ahy)).
ahx=ahx′/ (( ahx′ 2 +ahy′ 2 ) 1/2 )
ahy=ahy′ /(( ahx′ 2 +ahy′ 2 ) 1/2 )
The inclination vector vah is calculated by the above expressions. The CPU 10 stores data representing the calculated inclination vector on the main memory 13 as the updated inclination data 532 . The CPU 10 also stores the post-update inclination data 532 on the main memory 13 as the previous data 533 to be used in the next frame for calculating an inclination vector. After step S 18 , the CPU 10 terminates the inclination calculation processing.
As the controller 7 is moved more violently, the value of the length L 1 is farther from the magnitude of the acceleration of gravity (1 in this embodiment). Based on the length L 1 , the moving state of the controller 7 , i.e., whether the controller 7 is being moved violently, being moved slowly, or being still, can be found. As the value of the length L 1 is closer to 1, the effectiveness k is greater. Therefore, in this embodiment, the value of the effectiveness k is smaller as the controller k is moved more violently, whereas the value of the effectiveness k is greater as the controller k is closer to being still. When the controller 7 is being moved violently, it can be determined that the acceleration sensor 37 cannot accurately detect the acceleration of gravity. Therefore, the effectiveness k is smaller, and the inclination vector is closer to the previous vector. By contrast, when the controller 7 is closer to being still, it can be determined that the acceleration sensor 37 can accurately detect only the acceleration of gravity. Therefore, the effectiveness k is greater, and the inclination vector is closer to the preliminary vector. The inclination vector can be accurately calculated in step S 18 by varying the ratio between the preliminary vector and the previous vector (the effectiveness k) in accordance with how reliable the output of the acceleration sensor 37 is (how accurately the output of the acceleration sensor 37 represents the acceleration of gravity).
Returning to FIG. 14 , in step S 4 after step S 3 , the game processing based on the inclination of the controller 7 calculated in step S 3 is executed. Specifically, the inclination data D 32 stored on the main memory 13 is transferred (output) to the program for executing the game processing, and the game processing is executed in accordance with the program. The game processing is, for example, processing of moving a player character appearing in the game space in accordance with the inclination. When the inclination is not calculated in the inclination calculation processing (i.e., when the determination result in step S 12 shown in FIG. 15 is negative), the CPU 10 may execute the game processing based on an inclination represented by the previous inclination vector (previous vector) or execute the game processing assuming that the player did not provide any an input.
Next in step S 5 , a game image reflecting the result of the game processing executed in step S 4 is generated and displayed on the monitor 2 . Next in step S 6 , the CPU 10 determines whether or not to terminate the game. The determination in step S 6 is made in accordance with, for example, whether or not the player has cleared the game, or when a time limit is provided for the game, whether or not the time has passed. When the result of determination in step S 6 is negative, the processing returns to step S 2 and the processing loop in steps S 2 through S 6 is repeated until it is determined that the game is to be terminated. When the result of determination in step S 6 is positive, the CPU 10 terminates the game processing shown in FIG. 14 . So far, the game processing has been described.
As described above, according to this embodiment, an inclination vector is calculated using a preliminary vector and a previous vector. Thus, the inclination of the controller 7 can be calculated in real time. By varying the degree at which the previous vector is made closer to the preliminary vector (the effectiveness k) in accordance with the magnitude of the detected acceleration, the inclination can be more accurately calculated.
In the first embodiment, an inclination of the controller 7 in the x-y directions is calculated as an example. The present invention is applicable to calculating an inclination of the controller 7 in the x-y-z directions. In this case, the length of the acceleration vector is used instead of the length L 1 , and the preliminary vector and the inclination vectors are calculated as three-dimensional vectors.
Second Embodiment
Next, a game system including a game apparatus as an example of an inclination calculation apparatus according to a second embodiment of the present invention will be described. The hardware structure of the game system according to the second embodiment is similar to the game system 1 according to the first embodiment. In the second embodiment, the contents of the inclination calculation processing are different from those of the first embodiment. Hereinafter, the second embodiment will be described mainly regarding the differences thereof from the first embodiment.
FIG. 16 shows main data stored on the main memory 13 of the game apparatus 3 in the second embodiment. In FIG. 16 , data identical as that in FIG. 13 each bear an identical reference numeral and detailed descriptions thereof will be omitted.
In the second embodiment, the calculation processing data 53 includes second acceleration data 61 , three-axial length data 62 , and second variable data 63 in addition to the data shown in FIG. 13 . In the second embodiment, the acceleration data 521 will be referred as a “first acceleration data 521 ” to be distinguished from the second acceleration data 62 . The first acceleration data 521 represents the same content as that of the acceleration data 521 .
The second acceleration data 61 represents an acceleration detected by the acceleration sensor 37 in the x-y directions. Namely, the second acceleration data 61 is represented by a two-dimensional vector. In the second embodiment, a three-dimensional vector detected by the acceleration sensor 37 will be referred to as a “first acceleration vector Va” (=(ax, ay, az)),and the acceleration vector representing the acceleration in the x-y directions will be referred to as a “second acceleration vector Vc” ((cx, cy)).
The three-axial length data 62 represents a length L 2 of the first acceleration vector Va (a three-dimensional vector having an x component, a y component and a z component of the first acceleration vector Va).
The second variable data 63 represents a second variable d 2 , which indicates, in the case where the magnitude of the acceleration of gravity detected by the acceleration sensor 37 is l , how close to 1 the length L 2 of the first acceleration vector Va is. The second variable d 2 is used for calculating the effectiveness k together with the first variable d 1 .
FIG. 17 and FIG. 18 are flowcharts illustrating a detailed flow of the inclination calculation processing executed in the second embodiment. Except for the inclination calculation processing shown in FIG. 17 and FIG. 18 , the game processing in the second embodiment is substantially the same as that of the first embodiment.
In the second embodiment, the inclination calculation processing is executed as follows. First in step S 21 , a length L 2 in the three axial directions of the first acceleration vector Va is calculated. When the first acceleration vector Va is (ax, ay, az), the length L 2 is calculated in accordance with the following expression.
L 2=( ax 2 +ay 2 +az 2 ) 1/2
The CPU 10 stores data representing the calculated length L 2 on the main memory 13 as the three-axial length data 62 .
Next in step S 22 , it is determined whether or not the length L 2 calculated in step S 21 is within a predetermined range. The predetermined range is determined in advance, and is 0<L 2 ≦2 in this embodiment. When it is determined in step S 22 that the length L 2 is within the predetermined range, processing in step S 23 is executed. When it is determined in step S 22 that the length L 2 is not within the predetermined range, processing in steps S 23 through S 36 is skipped and the CPU 10 terminates the inclination calculation processing. Namely, when the result of the determination in step S 22 is negative, the inclination of the controller 7 is not calculated. The processing in step S 22 , like the processing in step S 12 in the first embodiment, is executed in order to prevent an inaccurate inclination of the controller 7 from being calculated when it is difficult to obtain an accurate inclination from the output of the acceleration sensor 37 , i.e., when the acceleration detected by the acceleration sensor 37 includes many components other than the acceleration of gravity.
By a series of processing in steps S 23 through S 25 , a second variable d 2 is calculated based on the length L 2 . In the series of processing, the second variable d 2 is calculated such that the value of the second variable d 2 is greater within the range of 0≦d 2 ≦1 as the length L 2 is closer to 1. First in step S 23 , it is determined whether or not the length L 2 is less than 1. The CPU 10 can find the value of the length L 2 by referring to the three-axial length data 62 stored on the main memory 13 . When it is determined in step S 23 that the length L 2 is less than 1, processing in step S 24 is executed. When it is determined in step S 23 that the length L 2 is equal to or greater than 1, processing in step S 25 is executed.
In step S 24 , the value of the length L 2 is set as the value of the second variable d 2 . In step S 25 , the second variable d 2 is calculated in accordance with the following expression.
d 2=2− L 2
Data representing the second variable d 2 obtained in step S 24 or S 25 is stored on the main memory 13 as the second variable data 63 . After step S 24 or S 25 , processing in step S 26 is executed.
In step S 26 , a second acceleration vector Vc is calculated based on the first acceleration vector Va. When the first acceleration vector Va is (ax, ay, az), the second vector Vc=(cx, cy) can be calculated in accordance with the following expressions.
cx=ax
cy=ay
The CPU 10 stores data representing the calculated second acceleration vector Vc on the main memory 13 as the second acceleration data 61 .
Next in step S 27 , a length L 1 of the second acceleration vector Vc in the two axial directions is calculated. The length L 1 can be calculated in accordance with the following expression.
L 1( cx 2 +Cy 2 ) 1/2
The CPU 10 stores data representing the calculated length L 1 on the main memory 13 as the two-axial length data 534 .
Next in step S 28 , it is determined whether or not the length L 1 calculated in step S 27 is 0. When it is determined in step S 28 that the length L 1 is not 0, processing in step S 29 is executed. When it is determined in step S 28 that the length L 1 is 0, processing in step S 29 through S 34 is skipped and the CPU 10 terminates the inclination calculation processing. Namely, when the result of the determination in step S 28 is positive, the inclination of the controller 7 is not calculated.
It is considered that the length L 1 is 0 in step S 28 when, for example, the controller 7 is in the up-down direction. In this case, an inclination to be calculated, i.e., an inclination in the x-y directions cannot be calculated. Therefore, in the second embodiment, the processing after step S 28 is skipped.
In step S 29 , a preliminary vector vh is calculated. In step S 29 , the preliminary vector vh can be calculated in accordance with the following expressions.
hx=−cy/L 1
hy=−cx/L 1
The CPU stores data representing the calculated preliminary vector vh (=(hx, by)) on the main memory 13 as the preliminary data 531 .
In the first and second embodiments, it is intended to calculate an inclination of the controller 7 in the x-y directions in the x-y-z coordinate system. This is why the preliminary vector vh is calculated as in steps S 13 and S 29 . In the case where it is intended to calculate an inclination in a coordinate system based on a space in which the controller 7 exists, the second acceleration vector Vc (=(cx, cy)) may be calculated as follows. For example, in step S 26 , the second acceleration vector may be calculated in accordance with the following expressions.
cx=ax
cy =( ay 2 +az 2 ) 1/2 ( ay< 0), cy=− ( ay 2 +az 2 ) 1/2 ( ay≦ 0)
By calculating the second acceleration vector Vc in this manner, an absolute inclination in the space can be calculated.
Next, by a series of processing in steps S 30 through S 32 , a first variable d 1 is calculated based on the length L 1 . In the series of processing, the first variable d 1 is calculated such that the value of the first variable d 1 is greater within the range of 0≦d 1 ≦1 as the value of the length L 1 is closer to 1. The processing in steps S 30 through S 32 is the same as the processing in steps S 14 through S 16 . Data representing the first variable d 1 obtained in steps S 31 or S 32 is stored on the main memory 13 as the first variable data 53 . After step S 31 or S 32 , processing in step S 33 is executed.
In step S 33 , an effectiveness k is calculated based on the first variable d 1 and the second variable d 2 . Specifically, the CPU 10 calculates the effectiveness k in accordance with the following expression.
k=d 1 2 ×d 2 2 ×A
In the above expression, A (>0) is a constant predetermined in the inclination calculation program 511 . Data representing constant A is stored on the main memory 13 in advance. The CPU 10 stores data representing the calculated effectiveness k on the main memory 13 as the effectiveness data 535 . As can be appreciated from the above expression, the effectiveness k is greater in the range of 0≦k≦1 as the value of the first variable d 1 is greater and as the value of the second variable d 2 is greater.
Next in step S 34 , an inclination vector vah is calculated. In the second embodiment, the inclination vector vah is calculated in the same manner as in the first embodiment. Namely, the processing in step S 34 is the same as the processing in step S 18 . After step S 34 , the CPU 10 terminates the inclination calculation processing.
As described above, according to the second embodiment, an acceleration in the x-y-z directions is used in order to calculate an inclination of the controller 7 in the x-y directions. Specifically, in the second embodiment, the game apparatus 3 varies the effectiveness k based on the magnitude of the acceleration in the x-y-z directions (length L 2 ). This magnitude represents the acceleration of the controller 7 more accurately than the length L 1 . Therefore, the moving state of the controller 7 can be more accurately determined using this magnitude. By varying the effectiveness k in accordance with this magnitude, the inclination of the controller 7 can be calculated more accurately. In the second embodiment, the effectiveness k is calculated using both the length L 1 and length L 2 . In other embodiments, the effectiveness k may be calculated using either the length L 1 or length L 2 .
In the first and second embodiments, the inclination of the controller 7 is represented as a vector. Alternatively, the inclination of the controller 7 may be represented by another element, for example, an angle with respect to a certain direction.
As described above, the present invention is usable for, for example, a game apparatus or a game program as described above for calculating an inclination of a device in real time using an acceleration detected by acceleration detection means.
While the invention has been described in detail, the foregoing description is in all aspects illustrative and not restrictive. It is understood that numerous other modifications and variations can be devised without departing from the scope of the invention.
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An inclination calculation apparatus within a game machine computes inclination of an input device having an acceleration sensor/detector capable of detecting acceleration in at least two axial directions. Programmed logic circuitry within the apparatus generates preliminary data which is representative of a current inclination and which is uniquely determined from acceleration data obtained from the acceleration sensor/detector. Programmed logic circuitry within the apparatus also regularly consecutively computes new/updated inclination vectors in real-time based on a previously computed inclination vector, a variable “effectiveness” valve and a current inclination vector, where the effectiveness value is a correction factor that represents the degree to which the direction of the previously computed inclination vector must be made closer to the direction of the current inclination vector to result in a direction for the new/updated inclination which more accurately reflects the actual inclination of the input device at the time the acceleration data is acquired.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to sweeping vehicles for sweeping roads or other surfaces.
2. Description of the Prior Art
Sweeping vehicles have been proposed with low pressure delivery and with a sweeping and picking up assembly having a suction mouth connected by a suction pipe with a rubbish separator or container. By means of suction applied to the mouth, sweepings fed from sweeping means mounted ahead of the mouth are picked up and delivered to the rubbish container.
The suction mouth normally comprises a duct extending at its extremity into a funnel shape or rectangular or other cross-section. With previously proposed arrangements, there occurs phenomenon which may be termed as a suction vortex effect and which causes small particles of dirt to be hurled, with a force depending on the strength and speed of the suction stream, from the suction zone of the mouth back on to the surface being swept so that they are not picked up. Effective sweeping and picking up can only be achieved by using additional aids.
In order to reduce the effects of this phenomenon, it has been proposed to provide the suction mouth, in addition to a conventional seal of an elastic material, with sealing elements such as strips of bristle. This arrangement does not, however, operate satisfactorily.
It has also been proposed to arrange air nozzles behind the mouth and which are supplied with air from the exhaust section of the fan producing the suction stream, the air discharged from the nozzles acting to prevent discharge of dirt particles from the suction zone. This arrangement requires a greater number of constructional elements and thus presents from a technical point of view an expensive solution. Further it is essential that the whole arrangement of suction mouth with jets shall be completely sealed behind the surface being swept since otherwise, in dry weather, the air blast, full of dust, will overflow to the outside. This effect is particularly likely to occur when uneven surfaces are swept as for example paved streets, and gutters, which is a disadvantage as the joints between the paving stones inevitably cause breakup of the air under the sealing elements which likewise encourages an outflow of the air blast. This previously proposed sweeping vehicle is thus limited to use on concrete roads or asphalted surfaces.
SUMMARY OF THE INVENTION
According to the present invention, there is provided in a sweeping vehicle, a sweeping and collecting assembly, said assembly comprising means defining a suction mouth, said mouth having an inlet facing in the direction of travel of the vehicle and being inclined at an acute angle with respect to the surface to be swept, and air guide means located behind the inlet with respect to the direction of travel of the vehicle, said guide means being arranged to extend generally parallel to the said surface, and said guide means extending rearwardly from said inlet.
The inclination of the inlet of the suction mouth and thus the suction stream, with respect to the surface to be swept, results in an inclination of the suction duct defined by the mouth and a corresponding displacement of the suction vortex arising at the inlet. The direction of the radial centrifugal forces acting on the particulate rubbish and which are caused by the air vortex, does not extend parallel to the surface to be swept as occurs in the previously proposed arrangements, but strikes in the region of the rear wall of the suction duct at a known angle to the surface to be swept so that the particles of rubbish from the surface to be swept are hurled in the same direction and rebound, to be directed by the partial air stream from the air guide means and thus reach the main suction air stream.
In a preferred embodiment of the invention, the air guide means is connected to the rear wall of the suction mouth by an elastic joint so that when travelling over comparatively high obstacles e.g., projecting drain covers in built-up areas, the guide means can be turned upwards and rearwards. Advantageously, the guide means is adjustable in height.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the invention will now be described, by way of example only, with reference to the accompanying diagrammatic drawing, in which:
FIG. 1 is a side elevation of a sweeping vehicle according to the invention;
FIG. 2 is a schematic section showing a suction mouth of the vehicle; and
FIG. 3 is a side elevation, partly in section of the suction mouth shown in FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
As shown in FIG. 1, the vehicle comprises a chassis which carries a rubbish separator and collection container 2 fitted with a flap 3 for emptying the container and a space 4 for a motor driven fan assembly 5 and other associated machinery. Between the front and rear wheels of the vehicle a sweeping and suction assembly 6 is mounted, the assembly being suspended from the chassis 1. The assembly comprises a suction mouth 7, sealing elements 8, support and guidance means 9, support wheels 10 and sweeping brushes 11; the brushes 11 are located in front of the suction mouth 7 and act to sweep the rubbish from gutters and the like into the suction zone of the suction mouth 7.
As shown in FIG. 2, the suction mouth 7 has, at its upper end portion, a suction pipe-connection union 12 of circular cross-section, the remaining portion of the mouth 7 below the union 12 being progressively developed into the form of a body of rectangular cross-section. The front wall 14 and rear wall 14' of the suction mouth 7 are, in the region of the inlet 13, of the suction mouth 7 bent forwardly in a gentle curve with the result that the suction mouth inlet 13 faces towards the front of the vehicle in the direction of travel of the vehicle and makes a acute angle with the surface to be swept, the inlet 13 thus facing approximately in the direction of flow of suction air and rubbish mixture coming from the front. Preferably the inlet 13 of the suction mouth 7 is inclined to the surface being swept by an acute angle of between 10° and 70° an inclination of between 15° and 20° being particularly advantageous.
Instead of forming a bend in the suction mouth 7, the mouth can run straight and can be rearwardly inclined at a predetermined angle to the vertical, so that the inlet 13 of the suction mouth 7 is inclined as described above.
The rear wall 14' of the suction mouth 7 is angled towards the rear with a gentle curve 15 for partial air guidance at the lower end in such a way that the extension of the wall horizontally, which serves as an air guide means 16, lies parallel to the surface to be swept.
At the lower end of the front wall 14 adjacent the inlet 13, there is arranged a coarse pick-up flap 18 which is capable of being hinged upwardly towards the front about a pivot 17. This flap 18 serves as an extension of the front wall 14 of the suction mouth 7, and extends in the same direction. With heavy soiling the flap 18 can be swung up about pivot 17 by any suitable means.
The level of the suction mouth 7 is so fixed in operation that between the surface to be swept and the under surface of the coarse pick-up flap 18 on the one side as well as the air guide means 16 on the other side respectively, a correspondingly greater air aperture 18' or 16' is preserved.
As can be seen from FIG. 2, the direction of the air vortex produced is changed by means of the lower part of the suction mouth 7. The components of the radial centrifugal forces in the air vortex are inclined at the same angle to the surface to be swept as the inlet 13 of the suction mouth 7. The consequence of this is that the particulate rubbish, which in the previously proposed arrangement was thrown out of the rear, impinges on the swept surface adjacent the inlet 13, rebounds from this surface and is led back into the suction mouth 7 by means of the air stream directed through the aperture 16' by the air guide means 16. The correct operation of the suction air stream including the transported rubbish is maintained even when travelling over uneven ground so that a correction of the height of the suction mouth is not needed.
FIG. 3 shows further practical details of the suction mouth 7.
In practice, the rear wall 14' and the air guide means 16 is attached to it does not -- as shown schematically in FIG. 2 -- consist of a single part since the air guidance means 16 must move elastically to avoid contact with obstacles encountered. The rear wall 14' and the air guide means 16 are thus separated above the curve 15. The gap 15' thus formed at the curve is bridged by an elastic member 19 which is fixed to the above-mentioned components by means of clamping bars 20, 20' and screws 21, 21'.
The air guide means is secured in a selected position by means of an adjusting and locking arrangement 22. The adjustment is carried out by means of tensioning elements which, for example, may consist of a linkage with an articulated support or a chain or a steel cable which is articulated with the aid of strap joints 23, 23' to the rear wall 14' of the suction mouth and the rear edge of the air guide means 16.
In order that subsequent adjustment can be made to the height of the air guidance means 16 and of the air aperture 16', the tensioning elements 20, 21 are so constructed that after slackening the tightening screws 21 for the elastic member 19 and the air guide means 16, corresponding upwards or downwards adjustment is possible. In dependence on the height adjustment described above, corresponding adjustment will be required at the same time for the adjusting and locking arrangement 22. This can be achieved, for example, by providing the upper strap joint 23 with support points for the tension elements which are variable with height.
The arrangement of the suction mouth 7 as described above is independent of the kind of chassis on which it is mounted and of the design of the sweeping vehicle. The cross-sectional configuration and the construction of the suction mouth may differ from that shown.
By arranging the suction mouth in the manner described the adverse effects hitherto caused by the suction vortex are obviated in a simple and inexpensive manner, and an effective cleaning action is provided.
The air guide means is maintained at known distance from the surface to be swept, whereby an effective uptake is ensured when travelling over an uneven surface which is to be swept. At the same time it is possible to cleanse gutters, which present a discontinuity to the road surface, without the need for adjusting of the height of the suction mouth by altering the setting of its support wheels.
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A sweeping vehicle for sweeping roads and other surfaces comprises a suction mouth located behind a sweeping brush. The inlet portion of the suction mouth is inclined relative to the surface to be swept and faces in a direction towards the brush. Air guide means extending from a trailing edge of the suction mouth approximately parallel to the surface, acts to direct air towards the suction mouth. The arrangement of the suction mouth and air guide means prevents particles of dirt from being discharged from the zone of the suction mouth by a vortex within the suction mouth.
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BACKGROUND OF THE INVENTION
The present invention relates to a sacking connection for filling open-top sacks with dusty products, with two spreading flaps that can be pivoted around horizontal axes and with which are associated clamping jaws that can be pivoted around horizontal axes and hold the edge of the opening of the sack against the spreading flaps.
A sacking connection of this type is known from German Patent No. 1 948 229.
There are several problems involved in filling open-top sacks with dusty products. Aside from the effects on the environment that such products can have, especially if they are chemicals, there is a risk that the edge of the sack cannot be sealed reliably enough or only by expensive means because of dust buildup in the vicinity of the closure seam. The dust problem can lead, when plastic sacks are being sealed, for example, to the necessity of cleaning the inside surface of the closure-seam zone manually or mechanically, which can, however, depending on the type of dust and its chemical composition, still not be effective enough in many cases for the sack to be reliably sealed with a closure seam.
When the inside of the vicinity of the closure seam gets contaminated, it could result in a welded seam of a quality too poor to seal the sack. It may for example be necessary to clean the inner surface of the sack in the vicinity of welded seam that is to be applied, which entails additional expense.
The only alternatives, consequently, are to seal the sacks with a separately applied rider tape or to utilize valve sacks instead of open sacks. Both possibilities are, however, uneconomical because additional equipment is needed to apply the rider tape and because valve sacks are essentially more expensive to manufacture than open sacks.
Along with the need to solve the dust problem, however, there is that of achieving a loading efficiency equal to that of comparable but non-dusty products.
Further, the closure-seam area of sacks with folding sides cannot be mechanically cleaned. If the sides are not unfolded during the filling process the loading efficiency will be correspondingly low.
SUMMARY OF THE INVENTION
The object of the present invention is a sacking connection of the aforesaid type in which the applied and clamped edge of a folding-sided or flat sack being filled is effectively protected to the fullest extent at the inside surface of the closure-seam area against the penetration of dust while the sack is being filled and sealed.
This object is attained in accordance with the invention in that the front of the spreading flaps are connected by dustproof aprons made of a flexible material and fastened in the vicinity of the side edges of the flaps and, in the case of sacks with folding-sides, a folding device that can be displaced along with its means of folding from outside the sacking connection into the space inside the sacking connection is associated with each apron and, in the case of flat sacks, a spreading device that can be displaced outward from inside along with its means of spreading is associated with each apron and the means of folding or of spreading non-positively connect the edges of the sack opening with the aprons.
In one embodiment of the invention the spreading flaps are plates and bent sheets of metal are fastened in alignment with the plates to their vertical lateral edges and can be removed from them, and the plates and bent sheets are as wide as the sacks.
To obtain an unobjectionable seal between the bent sheet fastened thereto in the vicinity of the connecting seam, the apron overlaps the sheet in the vicinity of the connecting seam in the shape of a U. The apron can be provided with perforations for screwing flanges on the bent sheet.
At the outside of the bent sheet the apron merges with a strip of rubber or plastic that extends over the lower horizontal edge of the plate and against which the edge of the opening of the sack can be held with a clamping jaw.
The edge of the opening of the sack applied to and clamped against the sacking connection thus rests against the aforesaid strips on the plates and against the aprons that connect the plates at the front, specifically both during the filling process when the sacking connection is open and upon completion of the filling process when the sacking connection is closed.
The applied position of the edge of the opening of the sack in the vicinity of the lateral aprons is secured, depending on whether the sacks are folding-side or flat, by folding devices or spreading devices, preventing dust from building up on the inside surface of the edge of the sack opening while allowing the total opening to be exploited for filling.
When packaging dust-laden products in plastic sacks that are open at the top, it has been found that sacking connections according to the invention must accordingly be designed so that the edge of the opening of the sack will rest at all points against the outside of the spreading flaps and of the aprons on the front. When the spreading flaps are closed, every apron assumes the form of a tube or sacks with folding sides. The edge of the opening of a flat sack that is to be filled assumes the form of a convex lens when the spreading flaps are open. Each apron must accordingly be brought into a position that corresponds to the shape of the edge of the opening of the sack while the spreading flaps are opening.
Therefore, another object of the present invention is to improve the sacking connection, to include a spreading device that acts from the inside toward the outside on the aprons secured at the front against the spreading flaps which is of a simple design that does not prevent the edge of the opening of the sack from being applied to the sacking connection and reliably protects the inside surfaces of the vicinity of the closure seam from the effects of dust while the sack is being filled.
This object is attained in accordance with the invention in that the spreading device consists of two spreading fingers that project into the sack with their lower ends, that are positioned in the vertical midplane of the sacking connection, that are mounted in such a way that they can rotate around horizontal axes, and that can be pivoted outwardly out of the vicinity of the spreading flaps and clamping jaws with a concomitant elastic deformation of the aprons until the aprons rest non-positively against the edge of the opening of the sack.
The design of the spreading device as fingers that can be pivoted around a horizontal axis makes it possible to easily slide the interior parts of each apron, which form a side fold, out over the side edges of the spreading flaps so that the outer wall of each apron will rest tightly against the inside of the edge of the opening of the sack. At least the area where the welded seam is to be applied in a subsequent operation is accordingly effectively protected against the penetration of dust.
In one preferred embodiment, the folding finger, which rests against the apron on the outside, and the spreading finger, which rests against the apron on the inside, are mounted in such a way that they can rotate around a common horizontal axis so that the motion of both the folding finger and the spreading finger can be powered by a common drive mechanism. A special advantage in this case is that the axis is embodied in a driven shaft on which is clamped a holder to which the upper ends of the spreading and folding fingers are attached. This constitutes an especially simple design because one spreading and one folding finger is mounted in one holder.
The dust generated during filling will not get into the environment of a sacking connection equipped with a central filling tube or with filling aprons when the connection has an upper framework-like cover through which the filling tube or similar structure extends, with suctioning tubes positioned at one side of the filling tube or similar structure and suctioning the dust from above out of a filling opening that is sealed on all sides.
Preferred embodiments of the invention will now be described with reference to the attached drawings, wherein:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front elevation of the sacking connection with a sack applied in the opening and in the closure position and with an associated removal belt;
FIG. 2 is a view of the sacking connection from the direction indicated by arrow II in FIG. 1;
FIG. 3 is a section along line III--III in FIG. 2;
FIG. 4 is a detail of FIG. 3;
FIG. 5 is a section along line V--V in FIG. 2;
FIG. 6 is a front elevation of a sacking connection with a sack applied in the opening position in accordance with a second embodiment of the invention;
FIG. 7 is a front elevation of the sacking connection of FIG. 6 with the full sack in the closure position;
FIG. 8 is a top view in partial section of the state illustrated in FIG. 7;
FIG. 9 is a view of the sacking connection from the direction indicated by arrow IX in FIG. 6, showing however, the spreading device in both the rest and the operating positions;
FIG. 10 is a top view corresponding to FIG. 9,
FIG. 11 is a detail of FIG. 9; and
FIG. 12 is a section along line XII--XII in FIG. 11.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1-5, a pouring funnel 1 has an outlet connection 2 to the bottom edge of which is attached a flexible loading hose 3 made out of rubber or a rubber-like plastic and extending inside a sacking connection 4 to the extent that its bottom edge 5 is below the edge of the opening of a sack 28 clamped to the sacking connection 4.
Sacking connection 4 has two spreading flaps 8, 9 that can be pivoted around horizontal axes 6, 7 and with which are associated clamping jaws 10, 11, which can also be pivoted around horizontal axes 6, 7.
The spreading flaps 8, 9 are plates with bent sheets 12 fastened to their vertical lateral edges. Each plate and each sheet fastened to it is as wide as the sack.
In this embodiment bent sheets 12 are provided with screwing flanges 13 that are secured to spreading flaps 8, 9 with screws 14.
To obtain unobjectionable dustproofing in the vicinity of the connecting seam between bent sheets 12 and spreading flaps 8 and 9 the edge parts of an apron 15 made out of rubber or a rubber-like plastic overlap two mutually opposed bent sheets 12 in the vicinity of the connecting seam in the shape of a U. The apron is provided with perforations for the screwing flanges 13 of bent sheets 12 in the vicinity of the connecting seam.
Aprons 15 constitute the front sides of sacking connection 4.
Spreading flaps 8 and 9 have strips 16 of rubber or plastic that extend over their bottom horizontal outer edge. The clamping jaws 10 and 11 associated with spreading flaps 8 and 9 have strips 17 of rubber or plastic so that the upper edge of the sack is clamped fast between strips 16 and 17 in the vicinity of the flaps and jaws.
As will be evident from FIG. 5, the outer surface of strip 16 merges with the outer surface of apron 15 in the vicinity of bent sheet 12.
When folding-side sacks are applied to sacking connection 4, a folding device is associated with each of its front sides. The folding device has a folding piece 18 that is movably mounted in the vicinity of the midplane 19 of sacking connection 4 and acts from outside on the applied sack edge 28. The sack edge 28 is represented by the dot-and-dash lines in FIGS. 4 and 5.
Whereas FIG. 4 illustrates sacking connection 4 in the filling position, the phantom lines in FIG. 5 represent the position of apron 15 upon completion of the filling process and once the sacking connection has been closed. In this operating position folding pieces 18 assume their inside limiting position.
Above each folding device is a finger 22 that can be pivoted around an upper horizontal axis 20 and is subjected to the force of a spring 21, its lower end resting non-positively against apron 15 outside in the vicinity of vertical midplane 19.
Fingers 22 tension aprons 15 pre-folded and taut against the inside of sacking connection 4.
When sacking connection 4 is closed, the resilient fingers 22 assume the position represented in FIG. 2 by the broken lines. Aprons 15 are drawn in around bent sheets 12 and folded in at the bottom of spreading flaps 8 and 9, which are slightly opened, like a side fold.
In this embodiment sacking connection 4 is lowered into the opened edge of the sack with spreading flaps 8 and 9 closed and clamping jaws 10 and 11 open. When the sacking connection is opened, the edge of the sack is forced against clamping jaws 10 and 11 by spreading flaps 8 and 9 and the lateral aprons 15 are slightly tightened outward against the edge of the sack. This tightening of aprons 15 against the edge of the sack is reinforced by the bent sheets 12 completely tightening out the opened side folds inwardly. The edge of the sack is accordingly protected from the action of dust over its full extent.
The sack is filled with the dusty product from product reservoir 1 through loading hose 3. The air entrained by the product can escape into outside areas 23 between loading hose 3 and lateral aprons 15. The air or its dust-laden constituents can be suctioned out of areas 23 by means of a suction device 24 positioned above the horizontal pivoting axes 6 and 7 of spreading flaps 8 and 9.
While sacking connection 4 is being closed, the full sack remains clamped against spreading flaps 8 and 9 with the side folds folded in against the tension of lateral aprons 15 by folding pieces 18. The edge of the sack is accordingly protected from the action of dust over its full extent until sacking connection 4 is closed. The edge of the sack is then, in the closed position and while still clamped tight, grasped immediately below sacking connection 4 by grippers 25 before clamping jaws 10 and 11 are moved back into the opening position and the sacking connection pivoted upwardly.
The vertical range of movement of sacking connection 4 is represented in FIG. 1 by the marks representing its limiting positions.
The grippers 25 in this embodiment are, when the full sack is removed, displaced in synchronization with removal belt 26, which is equipped with trough-shaped sections 27 for positive accommodation of the base of the sacks 5 and which conveys them to a closing station.
As will be evident from FIG. 2, folding pieces 18 extent to some extend down out of sacking connection 4 when it is closed and grippers 25 grasp the edges of the sacks in the vicinity of these projecting parts. The grippers must accordingly have recesses appropriate to accommodate these parts.
Grippers 25 and removal belt 26 can also be positioned for removal to the side of sacking connection 4, in which case the closing equipment is also correspondingly positioned.
When flat sacks are to be applied to sacking connection 4, folding pieces 18 are dismounted and the mechanisms that drive the folding devices are equipped with U-shaped spreading fingers, so that the folding devices are transformed into spreading devices.
The U-shaped spreading fingers exhibit a component that extends down from an upper web, engages the rear of the apron, and extends into the vicinity of the edge of the opening of the sack. The spreading fingers force aprons 15 against the edge of the opening of the sack to produce a non-positive connection between the aprons and the edge of the opening in the vicinity of the lateral aprons as well once the edge of the opening of the sack has been clamped tight in the vicinity of the spreading flaps.
Aprons 15 extend over or almost over the total height of the spreading flaps.
Referring now to FIGS. 6-12, another embodiment is illustrated wherein the same elements have the same elements have the same labels as in FIGS. 1-5 and wherein a pouring funnel, not illustrated, with an outlet connection, also not illustrated, has a flexible loading hose 3 of rubber or a rubber-like plastic at its bottom edge and extending far enough inside a sacking connection 4 to the extent that its bottom edge 5 is below the edge of the opening of a sack clamped to the sacking connection 4.
Sacking connection 4 has two spreading flaps 8, 9 that can be pivoted around horizontal axes 6, 7 and with which are associated clamping jaws 10, 11, which can also be pivoted around horizontal axes 6, 7. The spreading flaps are plates with bent sheets 12 are fastened to their vertical lateral edges. Each plate and each sheet fastened to it is as wide as the sack.
In this embodiment also, bent sheets 12 are provided with screwing flanges 13 that are secured to spreading flaps 8, 9 with screws 14.
To obtain unobjectionable dustproofing in the vicinity of the connecting seam between bent sheets 12 and spreading flaps 8 and 9 the edge parts of an apron 15, made out of rubber or a rubber-like plastic overlap two mutually opposed bent sheets 12 in the vicinity of the connecting seam in the shape of a U. The apron is provided with perforations for the screwing flanges 13 of bent sheets 12 in the vicinity of the connecting seam.
Also in this embodiment, aprons 15 constitute the front sides of sacking connection 4.
Spreading flaps 8 and 9 have strips 16 of rubber or plastic that extend over their bottom horizontal outer edge. The clamping jaws 10 and 11 associated with spreading flaps 8 and 9 have strips 17 of rubber or plastic so that the upper edge of the sack is clamped fast between strips 16 and 17 in the vicinity of the flaps and jaws. The outer surface of strip 16 merges with the outer surface of apron 15 in the vicinity of bent sheet 12. There is a folding device and a spreading device on each front side of sacking connection 4. Each folding device consists essentially of a folding rod 30 that is rigidly connected to a holder 32 that is fixed on a shaft 31. Holder 32 also supports a spreading finger 33 that extends into the top of a sack 29. Apron 15 is located in the gap between folding rod 30 and spreading fingers 33. The edge of the opening of the sack surrounds the bottom of apron 15 with the upper edge of the sack below the bottom of folding rod 30.
A lever 34 is clamped to each shaft 31. The free end of lever 34 is freely articulated to the piston rod 35 of a piston-and-cylinder unit 36. As will be evident from FIG. 9 and 11, piston-and-cylinder unit 36 can pivot both folding rod 30 and spreading fingers 33 from a right-hand limiting position into a left-hand limiting position. FIG. 11 also illustrates a midposition. When folding rod 30 and spreading finger 33 are in the right-hand limiting position, spreading flaps 8 and 9 are closed or slightly open. When they are in the left-hand limiting position spreading flaps 8 and 9 are open to allow the sack to be filled. The open position of the spreading flaps is labeled 8', 9' in FIG. 12 and that of the clamping jaws 10' and 11'. As will be especially evident from FIG. 12, when spreading fingers 33 have been displaced into the left-hand limiting position, they force apron 15 non-positively against the inside of the sack in the vicinity of its upper edge to produce a sealing effect. The edge of the opening of the sack is accordingly effectively protected from the effects of dust during the filling process so that the closure seam can be applied without cleaning the edge.
As will be especially evident from FIG. 12, pivoting spreading finger 33 transforms apron 15 out of a side-fold shape into a flat shape while spreading flaps 8 and 9 are opening. When spreading flaps 8 and 9 are closed after the sack is full, piston-and-cylinder unit 36 will restore folding rod 30 and spreading fingers 33 to the right-hand limiting position. Folding rod 30, which acts on the outside of apron 15, simultaneously transforms it back into its original side-fold shape.
The sack is filled with the dusty product through loading hose 3. The air entrained by the product can escape through outside areas 23 between loading hose 3 and lateral aprons 15. The air or its dust-laden constituents can be suctioned out of areas 23 by means of a suction device 24 positioned above horizontal pivoting axes 6 and 7 and consisting essentially of tubes 37 and 38. As will be evident from FIG. 8, tubes 37 and 38 are positioned diagonally opposite each other.
Two receiving tubes 39 and 40 are positioned, also diagonally opposite each other, at the top of sacking connection 4. Each receiving tube 39 and 40 bears an interior pneumatic vibrator 41 or 42. Receiving tubes 39 and 40, and hence interior pneumatic vibrators 41 and 42 as well, can be lowered in a way that is not illustrated to the bottom of sack 29 while it is being filled. The lower position of interior pneumatic vibrators 41 and 42 is represented by the dot-and-dash lines in FIG. 6. Receiving tubes 39 and 40 can also have suction probes instead of interior pneumatic vibrators 41 and 42. As illustrated in FIGS. 6 and 7, when interior pneumatic vibrators 41 and 42 are not in operation they extend partly into the closed sacking connection.
While sacking connection 4 is being closed, the full sack remains clamped against spreading flaps 8 and 9 with the aprons being reshaped by the action of folding rods 30. The edge of the sack is accordingly protected from the action of dust over its full extent until sacking connection 4 is closed. The edge of the sack is then, in the closed position and while still clamped tight, grasped immediately below sacking connection 4 by grippers 25 before clamping jaws 10 and 11 are moved back into the opening position and the sacking connection advanced into the upper position. The full sack is subsequently removed by a removal belt that is not illustrated to the closing station.
It will be appreciated that the instant specification and claims are set forth by way of illustration and not limitation, and that various modifications and changes may be made without departing from the spirit and scope of the present invention.
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A sacking connection for filling sacks that are open at the top with dusty products has two spreading flaps that can be pivoted around horizontal axes. Clamping jaws can be pivoted around horizontal axes and hold the edge of the opening of the sack against the spreading flaps. The front of the spreading flaps are connected by dustproof aprons made of a flexible material and fastened in the vicinity of the side edges of the flaps. When folding-sided sacks are filled, a folding device that can be displaced along with its functions of folding from outside the sacking connection into the space inside the sacking connection is associated with each apron. When flat sacks are filled, a spreading device that can be displaced outward from inside along with its functions of spreading is associated with each apron. The functions of folding or of spreading connect the edge of the sack opening with the aprons to prevent dust from building up on the inside of the edge of the opening of the sack.
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RELATED APPLICATION DATA
[0001] The present application is a divisional of U.S. patent application Ser. No. 09/729,551, filed Dec. 04, 2000, now issued as U.S. Pat. No. ______.
FIELD OF THE INVENTION
[0002] This invention relates to a catalyst system comprising a catalyst compound and an activator used in an olefin polymerization process, preferably in the gas or slurry phase to produce polyolefins. The catalyst system preferably includes an activator, and a catalyst compound comprising a transition metal complexed with a facially coordinating tridentate bisamide ligand.
BACKGROUND OF THE INVENTION
[0003] Advances in polymerization and catalysis have resulted in the capability to produce many new polymers having improved physical and chemical properties useful in a wide variety of superior products and applications. With the development of new catalysts the choice of polymerization (solution, slurry, high pressure or gas phase) for producing a particular polymer has been greatly expanded. Also, advances in polymerization technology have provided more efficient, highly productive and economically enhanced processes. Especially illustrative of these advances is the development of technology utilizing bulky ligand metallocene catalyst systems. In a slurry or gas phase process typically a supported catalyst system is used, however, more recently unsupported catalyst systems are being used in these processes. For example, U.S. Pat. Nos. 5,317,036 and 5,693,727 and European publication EP-A-0 593 083 and PCT publication WO 97/46599 all describe various processes and techniques for introducing liquid catalysts to a reactor. There is a desire in the industry using this technology to reduce the complexity of the process, to improve the process operability, to increase product characteristics and to vary catalyst choices. Thus, it would be advantageous to have a process that is capable of improving one or more of these industry needs.
[0004] EP 0 893 454 A1 discloses bisamide based catalyst compounds that can be used for ethylene polymerization. WO 98/45039 discloses polymerization catalysts containing electron withdrawing amide ligands combined with group 3-10 or lanthanide metal compounds used with co-catalysts to polymerize olefins.
SUMMARY OF THE INVENTION
[0005] This invention relates to a catalyst system and polymerization processes using that catalyst system.
[0006] In one aspect, the invention relates to a catalyst system comprising one or more activators and at least one catalyst compound. The catalyst compound preferably comprises a group 3, 4, 5 lanthanide, or actinide metal atom bound to at least one anionic leaving group and also bound to at least three group 15 atoms, at least one of which is also bound to a group 15 or 16 atom through another group which may be a C 1 to C 20 hydrocarbon group, a heteroatom containing group, silicon, germanium, tin, or phosphorus, wherein the group 15 or 16 atom may also be bound to nothing or a hydrogen, a group 14 atom containing group, a halogen, or a heteroatom containing group, and wherein each of the two group 15 atoms are also bound to a cyclic group and may optionally be bound to hydrogen, a halogen, a heteroatom or a hydrocarbyl group, or a heteroatom containing group.
[0007] In a preferred embodiment, the catalyst compound is represented by the formula:
[0008] wherein
[0009] M is a group 3, 4 or 5 transition metal or a lanthanide or actinide group metal,
[0010] each X is independently an anionic leaving group,
[0011] n is the oxidation state of M,
[0012] a is 0 or 1,
[0013] m is the formal charge of the YZL ligand,
[0014] Y is a group 15 element,
[0015] Z is a group 15 element,
[0016] J is a C 1 to C 20 hydrocarbon group, a heteroatom containing group, silicon, germanium, tin, or phosphorus,
[0017] L is a group comprising a group 15 or 16 element,
[0018] R 1 and R 2 are independently a C 1 to C 20 hydrocarbon group, a heteroatom containing group, silicon, germanium, tin, or phosphorus,
[0019] R 1 and R 2 may also be interconnected to each other,
[0020] R 3 is hydrogen, a hydrocarbyl group or a heteroatom containing group,
[0021] R 4 and R 5 are independently an aryl group, a substituted aryl group, a cyclic alkyl group, a substituted cyclic alkyl group, or multiple ring system, and
[0022] R 6 and R 7 are independently absent or hydrogen, halogen, heteroatom or a hydrocarbyl group, or a heteroatom containing group.
[0023] By “formal charge of the YZL ligand” is meant the charge of the entire ligand absent the metal and the leaving groups X.
[0024] By “R 1 and R 2 may also be interconnected to each other” is meant that R 1 and R 2 may be bound to each other through other groups.
[0025] The activator is preferably an alumoxane, a modified alumoxane, a non-coordinating anion, a borane, a borate, a combination thereof or a conventional-type cocatalyst as described below. It appears preferably however, to use the alumoxanes and boranes together as the inventors have observed that alumoxanes alone and boranes alone do not appear activate the catalysts compounds nearly as well.
DETAILED DESCRIPTION OF THE INVENTION
[0026] In a preferred embodiment, one or more activators are combined with a catalyst compound represented by the formula:
[0027] M is a group 3, 4, or 5 transition metal or a lanthanide or actinide group metal, preferably a group 4, preferably zirconium or hafnium,
[0028] each X is independently an anionic leaving group, preferably hydrogen, a hydrocarbyl group, a heteroatom or a halogen,
[0029] n is the oxidation state of M, preferably +3, +4, or +5, preferably +4,
[0030] m is the formal charge of the YZL ligand, preferably 0, −1, −2 or −3, preferably −2,
[0031] L is a group 15 or 16 element, preferably nitrogen;
[0032] J is a C 1 to C 20 hydrocarbon group, a heteroatom containing group having up to twenty carbon atoms, preferably a C 1 to C 6 hydrocarbon group, preferably a C 1 to C 20 alkyl, aryl or aralkyl group, preferably a linear, branched or cyclic C 1 to C 20 alkyl or group, wherein the alkyl aryl or aralkyl group may be substituted or un-substituted and may contain heteroatoms, and J may form a ring structure with L;
[0033] Y is a group 15 element, preferably nitrogen or phosphorus,
[0034] Z is a group 15 element, preferably nitrogen or phosphorus,
[0035] R 1 and R 2 are independently a C 1 to C 20 hydrocarbon group, a heteroatom containing group having up to twenty carbon atoms, silicon, germanium, tin, or phosphorus, preferably a C 1 to C 6 hydrocarbon group, preferably a C 1 to C 20 alkyl, aryl or aralkyl group, preferably a linear, branched or cyclic C 1 to C 20 alkyl group, R 1 and R 2 may also be interconnected to each other,
[0036] R 3 is a hydrocarbon group, hydrogen, a halogen, a heteroatom containing group, preferably a linear, cyclic or branched alkyl group having 1 to 20 carbon atoms;
[0037] a is 1;
[0038] R 4 and R 5 are independently an aryl group, a substituted aryl group, a cyclic alkyl group, a substituted cyclic alkyl group, a cyclic aralkyl group, a substituted cyclic aralkyl group or multiple ring system, preferably having up to 20 carbon atoms, preferably between 3 and 10 carbon atoms, preferably a C 1 to C 20 hydrocarbon group, a C 1 to C 20 aryl group or a C 1 to C 20 aralkyl group, and
[0039] R 6 and R 7 are independently absent, or hydrogen, halogen, heteroatom or a hydrocarbyl group, preferably a linear, cyclic or branched alkyl group having 1 to 20 carbon atoms, more preferably absent.
[0040] An aralkyl group is defined to be a substituted aryl group.
[0041] In a preferred embodiment, R 4 and R 5 are independently a group represented by the following formula:
[0042] wherein
[0043] R 8 to R 12 are each independently hydrogen, a C 1 to C 40 alkyl group, a heteroatom, a heteroatom containing group containing up to 40 carbon atoms, preferably a C 1 to C 20 linear or branched alkyl group, preferably a methyl, ethyl, propyl or butyl group, any two R groups may form a cyclic group and/or a heterocyclic group. The cyclic groups may be aromatic. In a preferred embodiment, R 9 and R 10 are independently a methyl, ethyl, propyl or butyl group, in a preferred embodiment, R 9 and R 10 are methyl groups, and R 8 , R 11 and R 12 are hydrogen. In this embodiment, M is preferably zirconium or hafnium, most preferably zirconium; each of L, Y, and Z is nitrogen; each of R 1 and R 2 is —CH 2 —; R 3 is methyl; and R 6 and R 7 are absent.
[0044] The catalyst compounds described herein are preferably combined with one or more activators to form an olefin polymerization catalyst system. Preferred activators include alumoxanes, modified alumoxanes, non-coordinating anions, non-coordinating group 13 metal or metalliod anions, boranes, borates and the like. It is within the scope of this invention to use alumoxane or modified alumoxane as an activator, and/or to also use ionizing activators, neutral or ionic, such as tri (n-butyl) ammonium tetrakis (pentafluorophenyl) boron or a trisperfluorophenyl boron metalloid precursor which ionize the neutral metallocene compound. Other useful compounds include triphenyl boron, triethyl boron, tri-n-butyl ammonium tetraethylborate, triaryl borane and the like. Other useful compounds include aluminate salts as well.
[0045] In a preferred embodiment, MMAO3A (modified methyl alumoxane in heptane, commercially available from Akzo Chemicals, Inc. under the trade name Modified Methylalumoxane type 3A, (See U.S. Pat. No. 5,041,584) is combined with the metal compounds to form a catalyst system.
[0046] There are a variety of methods for preparing alumoxane and modified alumoxanes, non-limiting examples of which are described in U.S. Pat. Nos. 4,665,208, 4,952,540, 5,091,352, 5,206,199, 5,204,419, 4,874,734, 4,924,018, 4,908,463, 4,968,827, 5,308,815, 5,329,032, 5,248,801, 5,235,081, 5,157,137, 5,103,031, 5,391,793, 5,391,529, 5,041,584 5,693,838, 5,731,253, 5,041,584 and 5,731,451 and European publications EP-A-0 561 476, EP-B1-0 279 586 and EP-A-0 594-218, and PCT publication WO 94/10180, all of which are herein fully incorporated by reference.
[0047] Ionizing compounds may contain an active proton, or some other cation associated with but not coordinated to or only loosely coordinated to the remaining ion of the ionizing compound. Such compounds and the like are described in European publications EP-A-0 570 982, EP-A-0 520 732, EP-A-0 495 375, EP-A-0 426 637, EP-A-500 944, EP-A-0 277 003 and EP-A-0 277 004, and U.S. Pat. Nos. 5,153,157, 5,198,401, 5,066,741, 5,206,197, 5,241,025, 5,387,568, 5,384,299, 5,502,124 and 5,643,847, all of which are herein fully incorporated by reference. Other activators include those described in PCT publication WO 98/07515 such as tris (2,2′,2″-nonafluorobiphenyl) fluoroaluminate, which is fully incorporated herein by reference. Combinations of activators are also contemplated by the invention, for example, alumoxanes and ionizing activators in combinations, see, for example, PCT publications WO 94/07928 and WO 95/14044 and U.S. Pat. Nos. 5,153,157 and 5,453,410 all of which are herein fully incorporated by reference. Also, methods of activation such as using radiation and the like are also contemplated as activators for the purposes of this invention.
[0048] Useful activators include those selected from the group consisting of: trimethylammonium tetraphenylborate, triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tri(n-butyl)ammonium tetraphenylborate, tri(t-butyl)ammonium tetraphenylborate, N,N-dimethylanilinium tetraphenylborate, N,N-diethylanilinium tetraphenylborate, N,N-dimethyl-(2,4,6-trimethylanilinium) tetraphenylborate, trimethylammonium tetrakis(pentafluorophenyl)borate, triethylammonium tetrakis(pentafluorophenyl)borate, tripropylammonium tetrakis(pentafluorophenyl)borate, tri(n-butyl)ammonium tetrakis(pentafluorophenyl)borate, tri(sec-butyl)ammonium tetrakis(pentafluorophenyl) borate, N,N-dimethylanilinium tetrakis(pentafluorophenyl) borate, N,N-diethylanilinium tetrakis(pentafluorophenyl) borate, N,N-dimethyl-(2,4,6-trimethylanilinium) tetrakis(pentafluorophenyl) borate, trimethylammonium tetrakis-(2,3,4,6-tetrafluorophenylborate, triethylammonium tetrakis-(2,3,4,6-tetrafluorophenyl) borate, tripropylammonium tetrakis-(2,3,4,6-tetrafluorophenyl) borate, tri(n-butyl)ammonium tetrakis-(2,3,4,6-tetrafluoro-phenyl) borate, dimethyl(t-butyl)ammonium tetrakis-(2,3,4,6-tetrafluorophenyl) borate, N,N-dimethylanilinium tetrakis-(2,3,4,6-tetrafluorophenyl) borate, N,N-diethylanilinium tetrakis-(2,3,4,6-tetrafluoro-phenyl) borate, N,N-dimethyl-(2,4,6-trimethylanilinium)tetrakis-(2,3,4,6-tetrafluorophenyl) borate; di-(i-propyl)ammonium tetrakis(pentafluorophenyl) borate, dicyclohexylammonium tetrakis(pentafluorophenyl) borate; triphenylphosphonium tetrakis(pentafluorophenyl) borate, tri(o-tolyl)phosphonium tetrakis(pentafluorophenyl) borate, tri(2,6-dimethylphenyl)phosphonium tetrakis(pentafluorophenyl) borate, and mixtures thereof.
[0049] In another embodiment, a second catalyst compound may be present. the second catalyst compound mat be another compound as described above or may comprise a conventional-type transition metal catalyst.
Conventional-Type Transition Metal Catalysts
[0050] Conventional-type transition metal catalysts are those traditional Ziegler-Natta, vanadium and Phillips-type catalysts well known in the art. Such as, for example Ziegler-Natta catalysts as described in “Ziegler-Natta Catalysts and Polymerizations”, John Boor, Academic Press, New York, 1979. Examples of conventional-type transition metal catalysts are also discussed in U.S. Pat. Nos. 4,115,639, 4,077,904, 4,482,687, 4,564,605, 4,721,763, 4,879,359 and 4,960,741 all of which are herein fully incorporated by reference. The conventional-type transition metal catalyst compounds that may be used in the present invention include transition metal compounds from Groups 3 to 17, preferably 4 to 12, more preferably 4 to 6 of the Periodic Table of Elements.
[0051] These conventional-type transition metal catalysts may be represented by the formula: MR x , where M is a metal from Groups 3 to 17, preferably Group 4 to 6, more preferably Group 4, most preferably titanium; R is a halogen or a hydrocarbyloxy group; and x is the oxidation state of the metal M. Non-limiting examples of R include alkoxy, phenoxy, bromide, chloride and fluoride. Non-limiting examples of conventional-type transition metal catalysts where M is titanium include TiCl 4 , TiBr 4 , Ti(OC 2 H 5 ) 3 Cl, Ti(OC 2 H 5 )Cl 3 , Ti(OC 4 H 9 ) 3 Cl, Ti(OC 3 H 7 ) 2 Cl 2 , Ti(OC 2 H 5 ) 2 Br 2 , TiCl 3 .1/3AlCl 3 and Ti(OCl 2 H 25 )Cl 3 .
[0052] Conventional-type transition metal catalyst compounds based on magnesium/titanium electron-donor complexes that are useful in the invention are described in, for example, U.S. Pat. Nos. 4,302,565 and 4,302,566, which are herein fully incorporate by reference. The MgTiCl 6 (ethyl acetate) 4 derivative is particularly preferred.
[0053] British Patent Application 2,105,355 and U.S. Pat. No. 5,317,036, herein incorporated by reference, describes various conventional-type vanadium catalyst compounds. Non-limiting examples of conventional-type vanadium catalyst compounds include vanadyl trihalide, alkoxy halides and alkoxides such as VOCl 3 , VOCl 2 (OBu) where Bu=butyl and VO(OC 2 H 5 ) 3 ; vanadium tetra-halide and vanadium alkoxy halides such as VCl 4 and VCl 3 (OBu); vanadium and vanadyl acetyl acetonates and chloroacetyl acetonates such as V(AcAc) 3 and VOCl 2 (AcAc) where (AcAc) is an acetyl acetonate. The preferred conventional-type vanadium catalyst compounds are VOCl 3 , VCl 4 and VOCl 2 -OR where R is a hydrocarbon radical, preferably a C 1 to C 10 aliphatic or aromatic hydrocarbon radical such as ethyl, phenyl, isopropyl, butyl, propyl, n-butyl, iso-butyl, tertiary-butyl, hexyl, cyclohexyl, naphthyl, etc., and vanadium acetyl acetonates.
[0054] Conventional-type chromium catalyst compounds, often referred to as Phillips-type catalysts, suitable for use in the present invention include CrO 3 , chromocene, silyl chromate, chromyl chloride (CrO 2 Cl 2 ), chromium-2-ethyl-hexanoate, chromium acetylacetonate (Cr(AcAc) 3 ), and the like. Non-limiting examples are disclosed in U.S. Pat. Nos. 3,709,853, 3,709,954, 3,231,550, 3,242,099 and 4,077,904, which are herein fully incorporated by reference.
[0055] Still other conventional-type transition metal catalyst compounds and catalyst systems suitable for use in the present invention are disclosed in U.S. Pat. Nos. 4,124,532, 4,302,565, 4,302,566, 4,376,062, 4,379,758, 5,066,737, 5,763,723, 5,849,655, 5,852,144, 5,854,164 and 5,869,585 and published EP-A2 0 416 815 A2 and EP-A1 0 420 436, which are all herein incorporated by reference.
[0056] Other catalysts may include cationic catalysts such as AlCl 3 , and other cobalt, iron, nickel and palladium catalysts well known in the art. See for example U.S. Pat. Nos. 3,487,112, 4,472,559, 4,182,814 and 4,689,437 all of which are incorporated herein by reference.
[0057] Typically, these conventional-type transition metal catalyst compounds excluding some conventional-type chromium catalyst compounds are activated with one or more of the conventional-type cocatalysts described below.
Conventional-Type Cocatalysts
[0058] Conventional-type cocatalyst compounds for the above conventional-type transition metal catalyst compounds may be represented by the formula M 3 M 4 v X 2 c R 3 b-c , wherein M 3 is a metal from Group 1 to 3 and 12 to 13 of the Periodic Table of Elements; M 4 is a metal of Group 1 of the Periodic Table of Elements; v is a number from 0 to 1; each X 2 is any halogen; c is a number from 0 to 3; each R 3 is a monovalent hydrocarbon radical or hydrogen; b is a number from 1 to 4; and wherein b minus c is at least 1. Other conventional-type organometallic cocatalyst compounds for the above conventional-type transition metal catalysts have the formula M 3 R 3 k , where M 3 is a Group IA, IIA, IIB or IIIA metal, such as lithium, sodium, beryllium, barium, boron, aluminum, zinc, cadmium, and gallium; k equals 1, 2 or 3 depending upon the valency of M 3 which valency in turn normally depends upon the particular Group to which M 3 belongs; and each R 3 may be any monovalent hydrocarbon radical.
[0059] Non-limiting examples of conventional-type organometallic cocatalyst compounds useful with the conventional-type catalyst compounds described above include methyllithium, butyllithium, dihexylmercury, butylmagnesium, diethylcadmium, benzylpotassium, diethylzinc, tri-n-butylaluminum, diisobutyl ethylboron, diethylcadmium, di-n-butylzinc and tri-n-amylboron, and, in particular, the aluminum alkyls, such as tri-hexyl-aluminum, triethylaluminum, trimethylaluminum, and tri-isobutylaluminum. Other conventional-type cocatalyst compounds include mono-organohalides and hydrides of Group 2 metals, and mono- or di-organohalides and hydrides of Group 3 and 13 metals. Non-limiting examples of such conventional-type cocatalyst compounds include di-isobutylaluminum bromide, isobutylboron dichloride, methyl magnesium chloride, ethylberyllium chloride, ethylcalcium bromide, di-isobutylaluminum hydride, methylcadmium hydride, diethylboron hydride, hexylberyllium hydride, dipropylboron hydride, octylmagnesium hydride, butylzinc hydride, dichloroboron hydride, di-bromo-aluminum hydride and bromocadmium hydride. Conventional-type organometallic cocatalyst compounds are known to those in the art and a more complete discussion of these compounds may be found in U.S. Pat. Nos. 3,221,002 and 5,093,415, which are herein fully incorporated by reference.
[0060] The second catalyst compound may also be compound referred to as a metallocene, i.e. those mono-and bis-cyclopentadienyl group 4, 5 and 6 compounds described in U.S. Pat. Nos. 4,530,914, 4,805,561, 4,871,705, 4,937,299, 5,096,867, 5,120,867, 5,210,352, 5,124,418, 5,017,714, 5,057,475, 5,064,802, 5,278,264, 5,278,119, 5,304,614, 5,324,800, 5,347,025, 5,350,723, 5,391,790 5,391,789, 5,399,636, 5,539,124, 5,455,366, 5,534,473, 5,684,098, 5,693,730, 5,698,634, 5,710,297, 5,712,354, 5,714,427, 5,714,555, 5,728,641, 5,728,839, EP-A-0 591 756, EP-A-0 520 732, EP-A-0 578,838, EP-A-0 638,595, EP-A-0 420 436, EP-B1-0 485 822, EP-B1-0 485 823, EP-A-0 743 324, EP-B1-0 518 092, WO 91/04257, WO 92/00333, WO 93/08221, WO 93/08199, WO 94/01471, WO 94/07928, WO 94/03506 WO 96/20233, WO 96/00244, WO 97/15582, WO 97/15602, WO 97/19959, WO 97/46567, WO 98/01455, WO 98/06759 and WO 95/07140, all of which are fully incorporated by reference herein.
Supports, Carriers and General Supporting Techniques
[0061] The catalyst and/or the activator may be placed on, deposited on, contacted with, incorporated within, adsorbed, or absorbed in a support. Typically the support can be of any of the solid, porous supports, including microporous supports. Typical support materials include talc; inorganic oxides such as silica, magnesium chloride, alumina, silica-alumina; polymeric supports such as polyethylene, polypropylene, polystyrene, cross-linked polystyrene; and the like. Preferably the support is used in finely divided form. Prior to use the support is preferably partially or completely dehydrated. The dehydration may be done physically by calcining or by chemically converting all or part of the active hydroxyls. For more information on how to support catalysts please see U.S. Pat. No. 4,808,561 which discloses how to support a metallocene catalyst system. The techniques used therein are generally applicable for this invention.
[0062] For example, in a most preferred embodiment, the activator is contacted with a support to form a supported activator wherein the activator is deposited on, contacted with, vaporized with, bonded to, or incorporated within, adsorbed or absorbed in, or on, a support or carrier.
[0063] Support materials of the invention include inorganic or organic support materials, preferably a porous support material. Non-limiting examples of inorganic support materials include inorganic oxides and inorganic chlorides. Other carriers include resinous support materials such as polystyrene, functionalized or crosslinked organic supports, such as polystyrene divinyl benzene, polyolefins or polymeric compounds, or any other organic or inorganic support material and the like, or mixtures thereof.
[0064] The preferred support materials are inorganic oxides that include those Group 2, 3, 4, 5, 13 or 14 metal oxides. The preferred supports include silica, fumed silica, alumina (WO 99/60033), silica-alumina and mixtures thereof. Other useful supports include magnesia, titania, zirconia, magnesium chloride (U.S. Pat. No. 5,965,477), montmorillonite (EP-B1 0 511 665), phyllosilicate, zeolites, talc, clays (U.S. Pat. No. 6,034,187) and the like. Also, combinations of these support materials may be used, for example, silica-chromium, silica-alumina, silica-titania and the like. Additional support materials may include those porous acrylic polymers described in EP 0 767 184 B1, which is incorporated herein by reference. Other support materials include nanocomposites as described in PCT WO 99/47598, aerogels as described in WO 99/48605, spherulites as described in U.S. Pat. No. 5,972,510 and polymeric beads as described in WO 99/50311, which are all herein incorporated by reference. A preferred support is fumed silica available under the trade name Cabosil™ TS-610, available from Cabot Corporation. Fumed silica is typically a silica with particles 7 to 30 nanometers in size that has been treated with dimethylsilyldichloride such that a majority of hydroxyl groups are capped.
[0065] It is preferred that the support material, most preferably an inorganic oxide, has a surface area in the range of from about 10 to about 700 m 2 /g, pore volume in the range of from about 0.1 to about 4.0 cc/g and average particle size in the range of from about 5 to about 500 μm. More preferably, the surface area of the support is in the range of from about 50 to about 500 m 2 /g, pore volume of from about 0.5 to about 3.5 cc/g and average particle size of from about 10 to about 200 μm. Most preferably the surface area of the support is in the range from about 100 to about 1000 m 2 /g, pore volume from about 0.8 to about 5.0 cc/g and average particle size is from about 5 to about 100 μm. The average pore size of the support material of the invention typically has pore size in the range of from 10 to 1000 Å, preferably 50 to about 500 Å, and most preferably 75 to about 450 Å.
[0066] There are various methods known in the art for producing a supported activator or combining an activator with a support material. In an embodiment, the support material is chemically treated and/or dehydrated prior to combining with the catalyst compound, activator and/or catalyst system.
[0067] In one embodiment, an alumoxane is contacted with a support material, preferably a porous support material, more preferably a inorganic oxide, and most preferably the support material is silica.
[0068] In an embodiment, the support material having a various levels of dehydration, preferably 200° C. to 600° C. dehydrated silica, that is then contacted with an organoaluminum or alumoxane compound. In specifically the embodiment wherein an organoaluminum compound is used, the activator is formed in situ in or on the support material as a result of the reaction of, for example, trimethylaluminum and water.
[0069] In yet another embodiment, a Lewis base-containing support substrates will react with a Lewis acidic activator to form a support bonded Lewis acid compound. The Lewis base hydroxyl groups of silica are exemplary of metal/metalloid oxides where this method of bonding to a support occurs. This embodiment is described in U.S. patent application Ser. No. 09/191,922, filed Nov. 13, 1998, which is herein incorporated by reference.
[0070] Other embodiments of supporting an activator are described in U.S. Pat. No. 5,427,991, where supported non-coordinating anions derived from trisperfluorophenyl boron are described; U.S. Pat. No. 5,643,847 discusses the reaction of Group 13 Lewis acid compounds with metal oxides such as silica and illustrates the reaction of trisperfluorophenyl boron with silanol groups (the hydroxyl groups of silicon) resulting in bound anions capable of protonating transition metal organometallic catalyst compounds to form catalytically active cations counter-balanced by the bound anions; immobilized Group IIIA Lewis acid catalysts suitable for carbocationic polymerizations are described in U.S. Pat. No. 5,288,677; and James C. W. Chien, Jour. Poly. Sci.: Pt A: Poly. Chem, Vol. 29, 1603-1607 (1991), describes the olefin polymerization utility of methylalumoxane (MAO) reacted with silica (SiO 2 ) and metallocenes and describes a covalent bonding of the aluminum atom to the silica through an oxygen atom in the surface hydroxyl groups of the silica.
[0071] In an embodiment, the weight percent of the activator to the support material is in the range of from about 10 weight percent to about 70 weight percent, preferably in the range of from 20 weight percent to about 60 weight percent, more preferably in the range of from about 30 weight percent to about 50 weight percent, and most preferably in the range of from 30 weight percent to about 40 weight percent.
[0072] In another embodiment, the catalyst compounds and/or the activators are preferably combined with a support material such as a particulate filler material and then spray dried, preferably to form a free flowing powder. Spray drying may be by any means known in the art. Please see EP A 0 668 295 B1, U.S. Pat. No. 5,674,795 and U.S. Pat. No. 5,672,669 which particularly describe spray drying of supported catalysts. In general one may spray dry the catalysts by placing the catalyst compound and the optional activator in solution (allowing the catalyst compound and activator to react, if desired), adding a filler material such as silica or fumed silica, such as Gasil™ or Cabosil™, then forcing the solution at high pressures through a nozzle. The solution may be sprayed onto a surface or sprayed such that the droplets dry in midair. The method generally employed is to disperse the silica in toluene, stir in the activator solution, and then stir in the catalyst compound solution. Typical slurry concentrations are about 5-8 wt %. This formulation may sit as a slurry for as long as 30 minutes with mild stirring or manual shaking to keep it as a suspension before spray-drying. In one preferred embodiment, the makeup of the dried material is about 40-50 wt % activator (preferably alumoxane), 50-60 SiO 2 and about ˜2 wt % catalyst compound.
[0073] The first and second catalyst compounds may be combined at molar ratios of 1:1000 to 1000:1, preferably 1:99 to 99:1, preferably 10:90 to 90:10, more preferably 20:80 to 80:20, more preferably 30:70 to 70:30, more preferably 40:60 to 60:40. The particular ratio chosen will depend on the end product desired and/or the method of activation. One practical method to determine which ratio is best to obtain the desired polymer is to start with a 1:1 ratio, measure the desired property in the product produced and adjust the ratio accordingly.
[0074] The melt index (and other properties) of the polymer produced may be changed by manipulating hydrogen concentration in the polymerization system by:
[0075] 1) changing the amount of the first catalyst in the polymerization system, and/or
[0076] 2) changing the amount of the second catalyst, if present, in the polymerization system, and/or
[0077] 3) adding hydrogen to the polymerization process; and/or
[0078] 4) changing the amount of liquid and/or gas that is withdrawn and/or purged from the process; and/or
[0079] 5) changing the amount and/or composition of a recovered liquid and/or recovered gas returned to the polymerization process, said recovered liquid or recovered gas being recovered from polymer discharged from the polymerization process; and/or
[0080] 6) using a hydrogenation catalyst in the polymerization process; and/or
[0081] 7) changing the polymerization temperature; and/or
[0082] 8) changing the ethylene partial pressure in the polymerization process; and/or
[0083] 9) changing the ethylene to hexene ratio in the polymerization process; and/or
[0084] 10) changing the activator to transition metal ratio in the activation sequence.
[0085] In a preferred embodiment, the hydrogen concentration in the reactor is about 200-2000 ppm, preferably 250-1900 ppm, preferably 300-1800 ppm, preferably 350-1700 ppm, preferably 400-1600 ppm, preferably 500-1500 ppm, preferably 500-1400 ppm, preferably 500-1200 ppm, preferably 600-1200 ppm, preferably 700-1100 ppm, more preferably 800-1000 ppm.
[0086] In general the catalyst compound(s) and the activator(s) are combined in ratios of about 1000:1 to about 0.5:1. In a preferred embodiment, the metal compounds and the activator are combined in a ratio of about 300:1 to about 1: 1, preferably about 150:1 to about 1: 1, for boranes, borates, aluminates, etc. the ratio is preferably about 1:1 to about 10:1 and for alkyl aluminum compounds (such as diethylaluminum chloride combined with water) the ratio is preferably about 0.5:1 to about 10:1.
[0087] The catalyst system, the catalyst compounds and or the activator (whether spray dried or not) are preferably introduced into the reactor in one or more solutions or one or more slurries. In one embodiment, a solution of the activated catalyst compound(s) in an alkane such as pentane, hexane, toluene, isopentane or the like is introduced into a gas phase or slurry phase reactor. In another embodiment, a slurry of the activated catalyst compound(s) is introduced into a gas phase or slurry phase reactor. The slurry is preferably a suspension of particulate materials in a diluent medium. Preferably the slurry comprises mineral oil or other hydrocarbon as the diluent, typically an alkane having from 3 to 7 carbon atoms, preferably a branched alkane can be used as the diluent. The medium employed should be liquid under the conditions of polymerization and relatively inert. When a propane medium is used the process must be operated above the reaction diluent critical temperature and pressure. Preferably, a hexane or an isobutane medium is employed.
[0088] In another embodiment, a slurry of the catalyst compound(s) in mineral oil or an alkane such as pentane, hexane, toluene, isopentane or the like is combined with a solution of the activator and is introduced into a gas phase or slurry phase reactor. In another embodiment, the catalysts system or the components can be introduced into the reactor in a suspension or an emulsion. In one embodiment, the catalyst compound(s) are contacted with the activator in a solvent and just before the solution is fed into a gas or slurry phase reactor.
[0089] Solutions of the catalyst compounds are prepared by taking the catalyst compound and dissolving it in any solvent such as an alkane, toluene, xylene, etc. The solvent may first be purified in order to remove any poisons that may affect the catalyst activity, including any trace water and/or oxygenated compounds. Purification of the solvent may be accomplished by using activated alumina and activated supported copper catalyst, for example. The catalyst is preferably completely dissolved into the solution to form a homogeneous solution. multiple catalysts may be dissolved into the same solvent, if desired. Once the catalysts are in solution, they may be stored indefinitely until use.
[0090] A slurry used in the process of this invention is typically prepared by suspending the activator and/or catalyst compound in a liquid diluent. The liquid diluent is typically an alkane having from 3 to 7 carbon atoms, preferably a branched alkane or an organic composition such as mineral oil The diluent employed should be liquid under the conditions of polymerization and relatively inert. The concentration of the components in the slurry is controlled such that a desired ratio of catalyst compound(s) to activator, and/or catalyst compound to catalyst compound is fed into the reactor. The components are generally fed into the polymerization reactor as a mineral oil slurry. Solids concentrations in oil are about 10 to 15 weight %, preferably 11-14 weight %. In some embodiments, the spray dried particles are <˜10 micrometers in size from the lab-scale Buchi spray-dryer, while the scaled up rotary atomizers can create particles ˜25 micrometers, compared to conventional supported catalysts which are ˜50 micrometers. In a preferred embodiment, the particulate filler has an average particle size of 0.001 to 1 microns, preferably 0.001 to 0.1 microns.
Polymerization Process
[0091] The metal compounds and catalyst systems described above are suitable for use in any polymerization process, including solution, gas or slurry processes or a combination thereof, most preferably a gas or slurry phase process.
[0092] In one embodiment, this invention is directed toward the polymerization or copolymerization reactions involving the polymerization of one or more monomers having from 2 to 30 carbon atoms, preferably 2-12 carbon atoms, and more preferably 2 to 8 carbon atoms. The invention is particularly well suited to the copolymerization reactions involving the polymerization of one or more olefin monomers of ethylene, propylene, butene-1, pentene-1, 4-methyl-pentene-1, hexene-1, octene-1, decene-1,3-methyl-pentene-1, 3,5,5-trimethyl-hexene-1 and cyclic olefins or a combination thereof. Other monomers can include vinyl monomers, diolefins such as dienes, polyenes, norbornene, norbornadiene monomers. Preferably a copolymer of ethylene is produced, where the comonomer is at least one alpha-olefin having from 4 to 15 carbon atoms, preferably from 4 to 12 carbon atoms, more preferably from 4 to 8 carbon atoms and most preferably from 4 to 7 carbon atoms.
[0093] In another embodiment, ethylene or propylene is polymerized with at least two different comonomers to form a terpolymer. The preferred comonomers are a combination of alpha-olefin monomers having 4 to 10 carbon atoms, more preferably 4 to 8 carbon atoms, optionally with at least one diene monomer. The preferred terpolymers include the combinations such as ethylene/butene-1/hexene-1, ethylene/propylene/butene-1, propylene/ethylene/hexene-1, ethylene/propylene/ norbornene and the like.
[0094] In a particularly preferred embodiment, the process of the invention relates to the polymerization of ethylene and at least one comonomer having from 4 to 8 carbon atoms, preferably 4 to 7 carbon atoms. Particularly, the comonomers are butene-1, 4-methyl-pentene-1, hexene-1 and octene-1, the most preferred being hexene-1 and/or butene-1.
[0095] Typically in a gas phase polymerization process a continuous cycle is employed where in one part of the cycle of a reactor system, a cycling gas stream, otherwise known as a recycle stream or fluidizing medium, is heated in the reactor by the heat of polymerization. This heat is removed from the recycle composition in another part of the cycle by a cooling system external to the reactor. Generally, in a gas fluidized bed process for producing polymers, a gaseous stream containing one or more monomers is continuously cycled through a fluidized bed in the presence of a catalyst under reactive conditions. The gaseous stream is withdrawn from the fluidized bed and recycled back into the reactor. Simultaneously, polymer product is withdrawn from the reactor and fresh monomer is added to replace the polymerized monomer. (See for example U.S. Pat. Nos. 4,543,399, 4,588,790, 5,028,670, 5,317,036, 5,352,749, 5,405,922, 5,436,304, 5,453,471, 5,462,999, 5,616,661 and 5,668,228 all of which are fully incorporated herein by reference.)
[0096] The reactor pressure in a gas phase process may vary from about 10 psig (69 kPa) to about 500 psig (3448 kPa), preferably in the range of from about 100 psig (690 kPa) to about 400 psig (2759 kPa), preferably in the range of from about 200 psig (1379 kPa) to about 400 psig (2759 kPa), more preferably in the range of from about 250 psig (1724 kPa) to about 350 psig (2414 kPa).
[0097] The reactor temperature in the gas phase process may vary from about 30° C. to about 120° C., preferably from about 60° C. to about 115° C., more preferably in the range of from about 75° C. to 110° C., and most preferably in the range of from about 85° C. to about 110° C. Altering the polymerization temperature can also be used as a tool to alter the final polymer product properties.
[0098] The productivity of the catalyst or catalyst system is influenced by the main monomer partial pressure. The preferred mole percent of the main monomer, ethylene or propylene, preferably ethylene, is from about 25 to 90 mole percent and the monomer partial pressure is in the range of from about 75 psia (517 kPa) to about 300 psia (2069 kPa), which are typical conditions in a gas phase polymerization process. In one embodiment, the ethylene partial pressure is about 220 to 240 psi (1517-1653 kPa). In another embodiment, the molar ratio of hexene to ethylene in the reactor is 0.03:1 to 0.08:1.
[0099] In a preferred embodiment, the reactor utilized in the present invention and the process of the invention produce greater than 500 lbs of polymer per hour (227 Kg/hr) to about 200,000 lbs/hr (90,900 Kg/hr) or higher of polymer, preferably greater than 1000 lbs/hr (455 Kg/hr), more preferably greater than 10,000 lbs/hr (4540 Kg/hr), even more preferably greater than 25,000 lbs/hr (11,300 Kg/hr), still more preferably greater than 35,000 lbs/hr (15,900 Kg/hr), still even more preferably greater than 50,000 lbs/hr (22,700 Kg/hr) and most preferably greater than 65,000 lbs/hr (29,000 Kg/hr) to greater than 100,000 lbs/hr (45,500 Kg/hr).
[0100] Other gas phase processes contemplated by the process of the invention include those described in U.S. Pat. Nos. 5,627,242, 5,665,818 and 5,677,375, and European publications EP-A-0 794 200, EP-A-0 802 202 and EP-B-634 421 all of which are herein fully incorporated by reference.
[0101] A slurry polymerization process generally uses pressures in the range of from about 1 to about 50 atmospheres and even greater and temperatures in the range of 0° C. to about 120° C. In a slurry polymerization, a suspension of solid, particulate polymer is formed in a liquid polymerization diluent medium to which ethylene and comonomers and often hydrogen along with catalyst are added. The suspension including diluent is intermittently or continuously removed from the reactor where the volatile components are separated from the polymer and recycled, optionally after a distillation, to the reactor. The liquid diluent employed in the polymerization medium is typically an alkane having from 3 to 7 carbon atoms, preferably a branched alkane. The medium employed should be liquid under the conditions of polymerization and relatively inert. When a propane medium is used the process must be operated above the reaction diluent critical temperature and pressure. Preferably, a hexane or an isobutane medium is employed.
[0102] In one embodiment, a preferred polymerization technique of the invention is referred to as a particle form polymerization, or a slurry process where the temperature is kept below the temperature at which the polymer goes into solution. Such technique is well known in the art, and described in for instance U.S. Pat. No. 3,248,179 which is fully incorporated herein by reference. The preferred temperature in the particle form process is within the range of about 185° F. (85° C.) to about 230° F. (110° C.). Two preferred polymerization methods for the slurry process are those employing a loop reactor and those utilizing a plurality of stirred reactors in series, parallel, or combinations thereof. Non-limiting examples of slurry processes include continuous loop or stirred tank processes. Also, other examples of slurry processes are described in U.S. Pat. No. 4,613,484, which is herein fully incorporated by reference.
[0103] In another embodiment, the slurry process is carried out continuously in a loop reactor. The catalyst as a solution, as a suspension, as an emulsion, as a slurry in isobutane or as a dry free flowing powder is injected regularly to the reactor loop, which is itself filled with circulating slurry of growing polymer particles in a diluent of isobutane containing monomer and comonomer. Hydrogen, optionally, may be added as a molecular weight control. The reactor is maintained at pressure of about 525 psig to 625 psig (3620 kPa to 4309 kPa) and at a temperature in the range of about 140° F. to about 220 ° F. (about 60° C. to about 104° C.) depending on the desired polymer density. Reaction heat is removed through the loop wall since much of the reactor is in the form of a double-jacketed pipe. The slurry is allowed to exit the reactor at regular intervals or continuously to a heated low pressure flash vessel, rotary dryer and a nitrogen purge column in sequence for removal of the isobutane diluent and all unreacted monomer and comonomers. The resulting hydrocarbon free powder is then compounded for use in various applications.
[0104] In an embodiment, the reactor used in the slurry process of the invention is capable of and the process of the invention is producing greater than 2000 lbs of polymer per hour (907 Kg/hr), more preferably greater than 5000 lbs/hr (2268 Kg/hr), and most preferably greater than 10,000 lbs/hr (4540 Kg/hr). In another embodiment, the slurry reactor used in the process of the invention is producing greater than 15,000 lbs of polymer per hour (6804 Kg/hr), preferably greater than 25,000 lbs/hr (11,340 Kg/hr) to about 100,000 lbs/hr (45,500 Kg/hr).
[0105] In another embodiment, in the slurry process of the invention the total reactor pressure is in the range of from 400 psig (2758 kPa) to 800 psig (5516 kPa), preferably 450 psig (3103 kPa) to about 700 psig (4827 kPa), more preferably 500 psig (3448 kPa) to about 650 psig (4482 kPa), most preferably from about 525 psig (3620 kPa) to 625 psig (4309 kPa).
[0106] In yet another embodiment, in the slurry process of the invention the concentration of ethylene in the reactor liquid medium is in the range of from about 1 to 10 weight percent, preferably from about 2 to about 7 weight percent, more preferably from about 2.5 to about 6 weight percent, most preferably from about 3 to about 6 weight percent.
[0107] A preferred process of the invention is where the process, preferably a slurry or gas phase process is operated in the absence of or essentially free of any scavengers, such as triethylaluminum, trimethylaluminum, tri-isobutylaluminum and tri-n-hexylaluminum and diethyl aluminum chloride, dibutyl zinc and the like. This preferred process is described in PCT publication WO 96/08520 and U.S. Pat. No. 5,712,352, which are herein fully incorporated by reference.
[0108] In another preferred embodiment, the one or all of the catalysts are combined with up to 10 weight % of a metal stearate, (preferably a aluminum stearate, more preferably aluminum distearate) based upon the weight of the catalyst system (or its components), any support and the stearate. In an alternate embodiment, a solution of the metal stearate is fed into the reactor. In another embodiment, the metal stearate is mixed with the catalyst and fed into the reactor separately. These agents may be mixed with the catalyst or may be fed into the reactor in a solution or a slurry with or without the catalyst system or its components. More information on using aluminum stearate type additives maybe found in U.S. Ser. No. 09/113,261 filed Jul. 10, 1998, which is incorporated by reference herein.
[0109] In another preferred embodiment, the supported catalysts combined with the activators are tumbled with 2 weight % of an antistat, such as a methoxylated amine, such as Witco's Kemamine AS-990 from ICI Specialties in Bloomington, Del.
[0110] Polyolefins, particularly polyethylenes, having a density of 0.89 to 0.97g/cm 3 can be produced using this invention. In particular polyethylenes having a density of 0.910 to 0.965, preferably 0.915 to 0.960, preferably 0.920 to 0.955 can be produced. In some embodiments, a density of 0.915 to 0.940 g/cm 3 would be preferred, in other embodiments densities of 0.930 to 0.970 g/cm 3 are preferred.
[0111] The polyolefins then can be made into films, molded articles (including pipes), sheets, wire and cable coating and the like. The films may be formed by any of the conventional techniques known in the art including extrusion, co-extrusion, lamination, blowing and casting. The film may be obtained by the flat film or tubular process which may be followed by orientation in an uniaxial direction or in two mutually perpendicular directions in the plane of the film to the same or different extents. Orientation may be to the same extent in both directions or may be to different extents. Particularly preferred methods to form the polymers into films include extrusion or coextrusion on a blown or cast film line.
[0112] The films produced may further contain additives such as slip, antiblock, antioxidants, pigments, fillers, antifog, UV stabilizers, antistats, polymer processing aids, neutralizers, lubricants, surfactants, pigments, dyes and nucleating agents. Preferred additives include silicon dioxide, synthetic silica, titanium dioxide, polydimethylsiloxane, calcium carbonate, metal stearates, calcium stearate, zinc stearate, talc, BaSO 4 , diatomaceous earth, wax, carbon black, flame retarding additives, low molecular weight resins, hydrocarbon resins, glass beads and the like. The additives may be present in the typically effective amounts well known in the art, such as 0.001 weight % to 10 weight %.
EXAMPLES
[0113] In order to provide a better understanding of the present invention including representative advantages thereof, the following examples are offered. The following compounds are well know in the art and are available from many different suppliers: TIBA is triisobutyl aluminum; MMAO is modified methyl alumoxane; and MAO is methyl alumoxane. Ph is phenyl. Me is methyl.
Example 1
Preparation of 2-(2-pyridyl)-1,3-propane-bis(2,6-dimethyl)aniline
[0114] 1.50 gms of 2-(2-pyridyl)-1,3-propaneditosylate (3.15 mmol) was combined with 5.0 mls 2,6-dimethylaniline in a 100 ml Schlenk flask with a stir bar. The flask was heated under nitrogen at 110° C. for 16 hrs, then was allowed to cool to room temperature. ˜20 mls diethyl ether was added and swirled until the viscous oil became miscible. The ether solution was extracted three times with water, followed by removal of the solvent in vacuo. The oil was transferred to a short path distillation apparatus and heated under full vacuum. The initial fraction distilling over at 35° C. was discarded. The remaining viscous oil was isolated. 1H NMR THF-d 8 8.64 (1H, m, py), 7.71 (1H, t, py), 7.51 (1H, d, py), 7.21 (1H, m, py), 6.86 (4H, d, meta-aniline), 6.68 (2H, t, para-aniline), 3.80 (2H, br, NH), 3.47 (2H, d, ArN(H)CHH), 3.26 (2H, d, ArN(H)CHH), 2.18 (12H, s, aniline Me), 1.66 (3H, s, MeC(CH 2 ) 2 (Py)).
Example 2
Preparation of 2-(2-pyridyl)-1,3-propane-bis(2,6-dimethyl)aniline Zirconium Dimethyl)
[0115] 0.234 gms (1.0 mmol) of ZrCl 4 was combined with 0.378 gms (1.0 mmol) 2-(2-pyridyl)-1,3-propane-bis(2,6-dimethyl)aniline and ˜10 mls toluene in a 100 ml Schlenk flask under a nitrogen atmosphere. The contents were heated to 90-100° C. for 20 hrs with stirring. The solids produced were filtered in the drybox and washed with additional toluene. Yield (0.523 gms, 86%) All of this material (0.86 mmol) was suspended in 15 mls diethyl ether and cooled to −78° C. under nitrogen in a Schlenk flask. 2.46 mls of 1.4 M MeLi in diethyl ether (3.44 mmol) was added dropwise. The flask was allowed to warm to room temperature over 3 hours. Solvent was removed in vacuo. The product was extracted with toluene followed by filtration to remove solids. 1H NMR C6D6 8.76 (1H, m, pyridyl), 6.53-7.11 (9H, m, pyridyl and aniline), 3.92 (2H, d, CHH), 2.74 (2H, d, CHH), 2.26 (12H, s, aniline Me), 0.96 (3H, s, MeC(CH 2 ) 2 (py)), 0.19 (6H, br, ZrMe). Over time, another resonance appeared at 0.156 ppm, presumably due to methane formation. The product was stable when stored as a solid under nitrogen.
[0116] This is a representation of the complex of Example 2:
Examples 3 to 12
[0117] Ethylene polymerizations using 2-(2-pyridyl)-1,3-propane-bis(2,6-dimethyl)aniline zirconium dimethyl were performed. Polymerizations in a slurry reactor were conducted as follows. After an appropriate bake-out period and subsequent cool-down under nitrogen, 500 cc's of hexanes were charged to a 1 liter autoclave reactor. 1-Hexene, if any, and scavenger, if any, were added to the reactor prior to heating. The reactor contents were heated to the desired temperature. A mixture of the catalyst and cocatalyst were prepared in the glovebox in an airtight syringe, removed to the reactor and injected into the reactor once it had reached reaction temperature. Ethylene immediately filled the system to obtain a total pressure of 150 psig (1.03 MPa) and was fed on demand thereafter. Polymerizations were conducted for 30 minutes. BBF indicates butyl branching frequency (per 1000C).
TABLE 1 Example umol Zr activator Ratio scavenger ratio temp hexene yield (gms) BBF (IR) 3 2 MAO + MMAO 1000 none 85 0 0 4 10 B(C6F5)3 1.2 TIBA 50 85 0 0 5 5 B(C6F5)3 7.5 MMAO 350 85 0 2 6 5 Ph3C B(C6F5)4 1.2 TIBA 50 65 0 0.8 7 5 Ph3C B(C6F5)4 1.2 TIBA 50 85 0 4.5 8 5 Ph3C B(C6F5)4 1.2 TIBA 50 95 0 0.1 9 5 Ph3C B(06F5)4 1.2 TIBA 50 85 20 3.2 22.5 10 5 PhN(Me)2H B(C6F5)4 1.2 TIBA 50 65 0 0 11 5 PhN(Me)2H B(06F5)4 1.2 TIBA 50 85 0 4.5 12 5 PhN(Me)2H B(C6F5)4 1.2 TIBA 50 85 20 5 19.9
[0118] Temperature in Table 1 is in ° C.
Examples 13 to 18
[0119] Hexene polymerizations using 2-(2-pyridyl)-1,3-propane-bis(2,6-dimethyl)aniline zirconium dimethyl). In a glovebox, five mls 1-hexene, stored over Na/K alloy under nitrogen, were purified by passing through an activated basic alumina column directly into 20 ml scintillation vials, each equipped with a stir bar. To each was added 0.25 ml of a 4.2 M stock solution of 2-(2-pyridyl)-1,3-propane-bis(2,6-dimethyl)aniline zirconium dimethyl in toluene. Stock solutions of the appropriate activator were prepared as follows and added to the appropriate vial: 1.15 ml of 0.865M TIBA/heptane solution to example 13; 0.31 ml of a 3.15M MAO/toluene solution for example 14, 0.57 ml of a 1.73M MMAO/heptane solution for example 15, and 1.0 ml of 1.2 mM B(C 6 F 5 ) 3 , or PhN(Me) 2 H B(C 6 F 5 ) 4 , or Ph 3 C B(C 6 F 5 ) 4 toluene solution for 16-18, respectively. The mixtures were capped and allowed to stir overnight. Observations were noted. Workup of 17 and 18 constituted stripped off the remaining 1-hexene. SEC analysis was conducted in THF using a polystyrene standard.
TABLE 2 Example umols Zl Activator ratio comments Mw (SEC) PDI (SEC) 13 1 TIBA 1000 no apparent reaction 14 1 MAO 1000 no apparent reaction 15 1 MMAO 1000 no apparent reaction 16 1 B(C6F5)3 1.2 no apparent reaction 17 1 PhN(Me)2H B(C6F5)4 1.2 solution viscous after overnight stirring 544,000 2.17 18 1 Ph3C B(C6F5)4 1.2 solution most viscous after overnight stirring 691,000 1.99
[0120] All documents described herein are incorporated by reference herein, including any priority documents and/or testing procedures. As is apparent form the foregoing general description and the specific embodiments, while forms of the invention have been illustrated and described, various modifications can be made without departing from the spirit and scope of the invention. Accordingly it is not intended that the invention be limited thereby.
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This invention relates to a composition of matter comprising the catalyst compound comprising a transition metal complexed with a facially coordinating tridentate bisamide ligand. The invention is also directed to a catalyst system or a supported catalyst system comprising this compound and an activator and to a process for using the catalyst system or supported catalyst system in a process for polymerizing olefin(s).
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to Korean Patent Application No. 10-2011-0115667, filed on Nov. 8, 2011 under 35 U.S.C. §119, the contents of which are herein incorporated by reference in their entireties.
TECHNICAL FIELD
[0002] Exemplary embodiments of the present invention relate to a method of driving a display panel and a display apparatus for performing the method. More particularly, exemplary embodiments of the present invention relate to a method of driving a display panel that can improve display quality when the display panel displays a two-dimensional (“2D”) image and a three-dimensional (“3D”) image and a display apparatus for performing the method.
DISCUSSION OF THE RELATED ART
[0003] Demand for displaying 3D images in video game or movie industries has contributed to development of liquid crystal display apparatuses that can display the 3D images.
[0004] Generally, stereoscopic image display apparatuses display 3D images using binocular parallax between two eyes of a human. For example, as two eyes of a human are spaced apart from each other, images viewed by the two eyes at different angles are inputted to the human brain.
[0005] Stereoscopic image display apparatuses may include a stereoscopic type and an auto-stereoscopic type. For example, the stereoscopic type may include an anaglyph type and a shutter glasses type. For example, the auto-stereoscopic type may include a barrier type, a lenticular type and a liquid crystal lens type.
[0006] Display apparatuses capable of selectively displaying 2D images and 3D images display the images without refraction or blocking in a 2D mode so that a viewer may recognize the 2D images. The display apparatuses refract or selectively block the images on the display panel in a 3D mode so that the viewer may recognize the 3D images.
[0007] In the 2D mode, a super patterned vertical alignment (“SPVA”) method independently driving high pixels and low pixels in unit pixels of the display panel may be used to improve a viewing angle.
[0008] When the SPVA method is applied to the 3D mode, the luminance of pixels may not be uniform due to the continuous shift of a viewpoint so that a moiré phenomenon may occur, and the luminance of images may decrease.
SUMMARY
[0009] Exemplary embodiments of the present invention provide a method of driving a display panel that can improve display quality when the display panel displays a two-dimensional (“2D”) image and a three-dimensional (“3D”) image and a display apparatus for performing the method of driving the display panel.
[0010] According to an exemplary embodiment, there is provided a method of driving a display panel. The method includes determining a driving mode including a two-dimensional (“2D”) mode and a three-dimensional (“3D”) mode and charging a voltage which varies according to the driving mode to at least one subpixel in a unit pixel of the display panel.
[0011] In an exemplary embodiment, the unit pixel includes a first subpixel and a second subpixel. A first voltage may be charged to the first subpixel and a second voltage is charged to the second subpixel in the 2D mode. The second voltage is different from the first voltage for at least one grayscale.
[0012] In an exemplary embodiment, a third voltage is charged to the first subpixel and a fourth voltage is charged to the second subpixel in the 3D mode. The fourth voltage is the same or substantially equal to the third voltage.
[0013] In an exemplary embodiment, the third and fourth voltages are the same or substantially equal to one of the first voltage and the second voltage.
[0014] In an exemplary embodiment, charging the voltage includes generating a gamma reference voltage which varies according to the driving mode.
[0015] In an exemplary embodiment, the unit pixel includes a first switching element connected to an N-th gate line and an M-th data line and a second switching element connected to an (N+1)-th gate line adjacent to the N-th gate line and the M-th data line. N and M are natural numbers.
[0016] In an exemplary embodiment, the unit pixel includes a first subpixel including the first switching element and a first pixel electrode connected to the first switching element and a second subpixel including the second switching element and a second pixel electrode connected to the second switching element. The second subpixel is adjacent to the first subpixel in an extending direction of the M-th data line.
[0017] In an exemplary embodiment, the unit pixel may include a first subpixel including the first switching element and a first pixel electrode connected to the first switching element and a second subpixel including the second switching element and a second pixel electrode connected to the second switching element. The second subpixel may be adjacent to the first subpixel in an extending direction of the N-th gate line.
[0018] In an exemplary embodiment, wherein the unit pixel may include a first switching element connected to an Nth gate line and an M-th data line and a second switching element connected to the N-th gate line and an (M+1)-th data line adjacent to the M-th data line.
[0019] In an exemplary embodiment, the unit pixel may include a first subpixel including the first switching element and a first pixel electrode connected to the first switching element and a second subpixel including the second switching element and a second pixel electrode connected to the second switching element. The second subpixel may be adjacent to the first subpixel in an extending direction of the M-th data line.
[0020] In an exemplary embodiment, the unit pixel may include a first subpixel including the first switching element and a first pixel electrode connected to the first switching element and a second subpixel including the second switching element and a second pixel electrode connected to the second switching element. The second subpixel may be adjacent to the first subpixel in an extending direction of the Nth gate line.
[0021] In an exemplary embodiment, the unit pixel may include a first subpixel, a second subpixel and a third switching element. The first subpixel may include a first switching element connected to an N-th gate line and an M-th data line, and a first pixel electrode connected to the first switching element. The second subpixel may include a second switching element connected to the N-th gate line and the M-th data line, and a second pixel electrode connected to the second switching element. The third switching element may include a gate electrode connected to an N-th control line, a source electrode connected to a second end of a capacitor, and a drain electrode connected to the second pixel electrode. A storage voltage may be applied to a first end of the capacitor.
[0022] In an exemplary embodiment, a voltage that varies according to the driving mode may be applied to the gate electrode of the third switching element.
[0023] In an exemplary embodiment, an N-th control signal may be applied to the gate electrode of the third switching element in the 2D mode. The N-th control signal having a gate on voltage after a gate on voltage of an N-th gate signal may be applied to the N-th gate line. A gate off voltage may be applied to the gate electrode of the third switching element in the 3D mode.
[0024] In an exemplary embodiment, the N-th control line may be connected to an (N+K)-th gate line in the 2D mode. The N-th control signal may be an (N+K)-th gate signal applied to the (N+K)-th gate line. K is a natural number.
[0025] In an exemplary embodiment, the unit pixel may include a first subpixel and a second subpixel. The first subpixel may include a first switching element connected to an N-th gate line, an M-th data line and a first pixel electrode, a first liquid crystal capacitor connected to the first pixel electrode and a common electrode and a first storage capacitor connected to the first pixel electrode and a first storage voltage line. The second subpixel may include a second switching element connected to the N-th gate line, the M-th data line and a second pixel electrode, a second liquid crystal capacitor connected to the second pixel electrode and the common electrode and a second storage capacitor connected to the second pixel electrode and a second storage voltage line.
[0026] In an exemplary embodiment, the charging the voltage may include generating storage voltages which vary according to the driving mode.
[0027] In an exemplary embodiment, a first storage voltage may be applied to the first storage voltage line and a second storage voltage may be applied to the second storage voltage line in the 2D mode. Each of the first storage voltage and the second storage voltage may periodically increase and decrease. The first storage voltage may have a phase different from a phase of the second storage voltage.
[0028] In an exemplary embodiment, a third storage voltage may be applied to the first storage voltage line and a fourth storage voltage may be applied to the second storage voltage line in the 3D mode. An amplitude of the third storage voltage may be smaller than an amplitude of the first storage voltage.
[0029] In an exemplary embodiment, a third storage voltage may be applied to the first storage voltage line and a fourth storage voltage may be applied to the second storage voltage line in the 3D mode. The third and fourth storage voltages may be direct-current (“DC”) voltages.
[0030] In an exemplary embodiment of a display apparatus according to the present invention, the display apparatus includes a display panel and a panel driver. The display panel includes a unit pixel having a plurality of subpixels. The panel driver configured to charge a voltage which varies according to a driving mode to at least one subpixel of the subpixels. The driving mode includes a 2D mode and a 3D mode.
[0031] In an exemplary embodiment, the unit pixel may include a first subpixel and a second subpixel. The panel driver is configured to charge a first voltage to the first subpixel and a second voltage to the second subpixel in the 2D mode. The second voltage may be different from the first voltage for at least one grayscale.
[0032] In an exemplary embodiment, the panel driver is configured to charge a third voltage to the first subpixel and a fourth voltage to the second subpixel in the 3D mode. The fourth voltage may be the same or substantially equal to the third voltage.
[0033] In an exemplary embodiment, the third and fourth voltages may be the same or substantially equal to one of the first voltage and the second voltage.
[0034] In an exemplary embodiment, the panel driver may include a gamma reference voltage generator configured to generate a gamma reference voltage which varies according to the driving mode.
[0035] In an exemplary embodiment, the unit pixel may include a first switching element connected to an N-th gate line and an M-th data line and a second switching element connected to an (N+1)-th gate line adjacent to the N-th gate line and the M-th data line.
[0036] In an exemplary embodiment, the unit pixel may include a first subpixel including the first switching element and a first pixel electrode connected to the first switching element and a second subpixel including the second switching element and a second pixel electrode connected to the second switching element. The second subpixel may be adjacent to the first subpixel in an extending direction of the M-th data line.
[0037] In an exemplary embodiment, the unit pixel may include a first subpixel including the first switching element and a first pixel electrode connected to the first switching element and a second subpixel including the second switching element and a second pixel electrode connected to the second switching element. The second subpixel may be adjacent to the first subpixel in an extending direction of the N-th gate line.
[0038] In an exemplary embodiment, the display apparatus may further include a liquid crystal lens on the display panel. The liquid crystal lens is configured to transmit an image from the display panel without being refracted in the 2D mode and to refract the image from the display panel in the 3D mode. The liquid crystal lens is configured to provide an image on the first subpixel to a first viewpoint and an image on the second subpixel to a second viewpoint in the 3D mode.
[0039] In an exemplary embodiment, the display apparatus may further include a liquid crystal barrier on the display panel. The liquid crystal barrier is configured to transmit an image from the display panel without being blocked in the 2D mode and to selectively block the image from the display panel in the 3D mode. The liquid crystal barrier is configured to provide an image on the first subpixel to a first viewpoint and an image on the second subpixel to a second viewpoint in the 3D mode.
[0040] In an exemplary embodiment, the unit pixel may include a first switching element connected to an N-th gate line and an M-th data line and a second switching element connected to the Nth gate line and an (M+1)-th data line adjacent to the M-th data line.
[0041] In an exemplary embodiment, the unit pixel may include a first subpixel including the first switching element and a first pixel electrode connected to the first switching element and a second subpixel including the second switching element and a second pixel electrode connected to the second switching element. The second subpixel may be adjacent to the first subpixel in an extending direction of the M-th data line.
[0042] In an exemplary embodiment, the unit pixel may include a first subpixel including the first switching element and a first pixel electrode connected to the first switching element and a second subpixel including the second switching element and a second pixel electrode connected to the second switching element. The second subpixel may be adjacent to the first subpixel in an extending direction of the N-th gate line.
[0043] In an exemplary embodiment, the display apparatus may further include a liquid crystal lens on the display panel. The liquid crystal lens is configured to transmit an image from the display panel without being refracted in the 2D mode and to refract the image from the display panel in the 3D mode. The liquid crystal lens is configured to provide an image on the first subpixel to a first viewpoint and an image on the second subpixel to a second viewpoint in the 3D mode.
[0044] In an exemplary embodiment, the display apparatus may further include a liquid crystal barrier on the display panel. The liquid crystal barrier may transmit an image from the display panel without being blocked in the 2D mode and to selectively block the image from the display panel in the 3D mode. The liquid crystal barrier is configured to provide an image on the first subpixel to a first viewpoint and an image on the second subpixel to a second viewpoint in the 3D mode.
[0045] In an exemplary embodiment, the unit pixel may include a first subpixel, a second subpixel and a third switching element. The first subpixel may include a first switching element connected to an N-th gate line and an M-th data line, and a first pixel electrode connected to the first switching element. The second subpixel may include a second switching element connected to the N-th gate line and the M-th data line, and a second pixel electrode connected to the second switching element. The third switching element may include a gate electrode connected to an N-th control line, a source electrode connected to a second end of a capacitor, and a drain electrode connected to the second pixel electrode. A storage voltage may be applied to a first end of the capacitor.
[0046] In an exemplary embodiment, a voltage that varies according to the driving mode may be applied to the gate electrode of the third switching element.
[0047] In an exemplary embodiment, an N-th control signal may be applied to the gate electrode of the third switching element in the 2D mode. The N-th control signal having a gate on voltage after a gate on voltage of an N-th gate signal may be applied to the N-th gate line. A gate off voltage may be applied to the gate electrode of the third switching element in the 3D mode.
[0048] In an exemplary embodiment, the N-th control line may be connected to an (N+K)-th gate line in the 2D mode. The N-th control signal may be an (N+K)-th gate signal applied to the (N+K)-th gate line.
[0049] In an exemplary embodiment, the unit pixel may include a first subpixel and a second subpixel. The first subpixel may include a first switching element connected to an N-th gate line, an M-th data line and a first pixel electrode, a first liquid crystal capacitor connected to the first pixel electrode and a common electrode and a first storage capacitor connected to the first pixel electrode and a first storage voltage line. The second subpixel may include a second switching element connected to the Nth gate line, the M-th data line and a second pixel electrode, a second liquid crystal capacitor connected to the second pixel electrode and the common electrode and a second storage capacitor connected to the second pixel electrode and a second storage voltage line.
[0050] In an exemplary embodiment, panel driver may include a storage voltage generator is configured to generate storage voltages which vary according to the driving mode.
[0051] In an exemplary embodiment, the storage voltage generator is configured to apply a first storage voltage to the first storage voltage line and a second storage voltage to the second storage voltage line in the 2D mode. Each of the first storage voltage and the second storage voltage may periodically increase and decrease. The first storage voltage may have a phase different from a phase of the second storage voltage.
[0052] In an exemplary embodiment, the storage voltage generator is configured to apply a third storage voltage to the first storage voltage line and a fourth storage voltage to the second storage voltage line in the 3D mode. An amplitude of the third storage voltage may be smaller than an amplitude of the first storage voltage.
[0053] In an exemplary embodiment, the storage voltage generator is configured to apply a third storage voltage to the first storage voltage line and a fourth storage voltage to the second storage voltage line in the 3D mode. The third and fourth storage voltages may be a DC voltages.
[0054] In an exemplary embodiment, the display apparatus may further include a liquid crystal lens on the display panel. The liquid crystal lens is configured to transmit an image from the display panel without being refracted in the 2D mode and to refract the image from the display panel in the 3D mode.
[0055] In an exemplary embodiment, the display apparatus may further include a liquid crystal barrier on the display panel. The liquid crystal barrier is configured to transmit an image from the display panel without being blocked in the 2D mode and to selectively block the image from the display panel in the 3D mode.
[0056] In an exemplary embodiment, the panel driver is configured to temporally divide image data and to apply the divided image data to the display panel in the 3D mode.
[0057] In an exemplary embodiment, the unit pixel may include a first unit pixel and a second unit pixel. The first unit pixel may correspond to a viewpoint different from a viewpoint of the second unit pixel. The display apparatus may further include a polarizing element disposed on the display panel. The polarizing element is configured to polarize a light transmitted through the first unit pixel and a light transmitted through the second unit pixel in different directions from each other in the 3D mode.
[0058] In an exemplary embodiment of a display panel according to the present invention, the display panel includes a pixel that includes first and second subpixels. The first and second subpixels are configured to be charged with different voltages, respectively, in a two dimensional driving mode and wherein both of the first and second subpixels are configured to be charged with one of the different voltages in a three dimensional driving mode.
[0059] According to the method of driving the display panel and the display apparatus for performing the method, a side visibility may be improved when the display panel displays the 2D image and a moiré may be prevented and a luminance of an image may be improved when the display panel displays the 3D image.
[0060] Thus, a display quality may be improved when the display panel displays the 2D image and the 3D image.
BRIEF DESCRIPTION OF THE DRAWINGS
[0061] The embodiments of the present invention will become more apparent in the detailed description with reference to the accompanying drawings, in which:
[0062] FIG. 1 is a block diagram illustrating a display apparatus according to an exemplary embodiment of the present invention;
[0063] FIG. 2 is a circuit diagram illustrating a unit pixel included in the display apparatus of FIG. 1 ;
[0064] FIG. 3 is a conceptual diagram illustrating a lookup table referred to by a timing controller of FIG. 1 ;
[0065] FIG. 4 is a conceptual diagram illustrating a lookup table referred to by a timing controller of a display apparatus according to an exemplary embodiment of the present invention;
[0066] FIG. 5 is a circuit diagram illustrating a unit pixel of a display apparatus according to an exemplary embodiment of the present invention;
[0067] FIG. 6 is a conceptual diagram illustrating a connecting structure between an output part of a data driver and a unit pixel of a display apparatus according to an exemplary embodiment of the present invention;
[0068] FIG. 7 is a circuit diagram illustrating a unit pixel of a display apparatus according to an exemplary embodiment of the present invention;
[0069] FIG. 8 is a conceptual diagram illustrating a connecting structure between an output part of a gate driver and a unit pixel of FIG. 7 ;
[0070] FIG. 9 is a block diagram illustrating a display apparatus according to an exemplary embodiment of the present invention;
[0071] FIG. 10 is a circuit diagram illustrating a unit pixel included in the display apparatus of FIG. 9 ;
[0072] FIG. 11 is a block diagram illustrating a storage voltage generator of FIG. 9 ;
[0073] FIG. 12 is a waveform diagram illustrating signals applied to the unit pixel of FIG. 9 ;
[0074] FIG. 13 is a storage voltage generator of a display apparatus according to an exemplary embodiment of the present invention;
[0075] FIG. 14 is a waveform diagram illustrating signals applied to a unit pixel of the display apparatus of FIG. 13 ;
[0076] FIG. 15 is a circuit diagram illustrating a unit pixel of a display apparatus according to an exemplary embodiment of the present invention; and
[0077] FIG. 16 is a circuit diagram illustrating a unit pixel of a display apparatus according to an exemplary embodiment of the present invention.
DETAILED DESCRIPTION
[0078] Hereinafter, exemplary embodiments of the present invention will be described in further detail with reference to the accompanying drawings, wherein the same reference numerals may be used to denote the same or substantially the same elements throughout the specification and the drawings. The present invention may be embodied in various different ways and should not be construed as limited to the exemplary embodiments described herein.
[0079] It will be understood that when an element or layer is referred to as being “on,” “connected to” or “coupled to” another element or layer, it can be directly on, connected or coupled to the other element or layer or intervening elements or layers may be present.
[0080] As used herein, the singular forms, “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.
[0081] FIG. 1 is a block diagram illustrating a display apparatus according to an exemplary embodiment of the present invention.
[0082] Referring to FIG. 1 , the display apparatus includes a display panel 100 and a panel driver. The panel driver includes a timing controller 200 , a gate driver 300 , a gamma reference voltage generator 400 and a data driver 500 .
[0083] The display panel 100 includes a plurality of gate lines GL, a plurality of data lines DL and a plurality of unit pixels connected to the gate lines GL and the data lines DL. The gate lines GL extend in a first direction D 1 and the data lines DL extend in a second direction D 2 crossing the first direction D 1 .
[0084] Each unit pixel includes a switching element (not shown), a liquid crystal capacitor (not shown) and a storage capacitor (not shown). The liquid crystal capacitor and the storage capacitor are electrically connected to the switching element. The unit pixels are disposed in a matrix form.
[0085] Each unit pixel includes a first subpixel and a second subpixel. A structure of the unit pixel is described in detail referring to FIG. 2 .
[0086] The timing controller 200 receives input image data RGB and an input control signal CONT from an external apparatus (not shown). The input image data include red image data R, green image data G and blue image data B. The input control signal CONT includes a driving mode signal representing a driving mode including a 2D mode and a 3D mode. According to an embodiment, the input control signal CONT further includes a master clock signal, a data enable signal. According to an embodiment, the input control signal CONT further includes a vertical synchronizing signal and a horizontal synchronizing signal.
[0087] The timing controller 200 generates a first control signal CONT 1 , a second control signal CONT 2 , a third control signal CONT 3 and a data signal DATA based on the input image data RGB and the input control signal CONT.
[0088] The timing controller 200 generates the first control signal CONT 1 for controlling an operation of the gate driver 300 based on the input control signal CONT and outputs the first control signal CONT 1 to the gate driver 300 . The first control signal CONT 1 includes the driving mode signal. According to an embodiment, the first control signal CONT 1 further includes a vertical start signal and a gate clock signal.
[0089] The timing controller 200 generates the second control signal CONT 2 for controlling an operation of the data driver 500 based on the input control signal CONT and outputs the second control signal CONT 2 to the data driver 500 . The second control signal CONT 2 includes the driving mode signal. According to an embodiment, the second control signal CONT 2 further includes a horizontal start signal and a load signal.
[0090] The timing controller 200 performs rendering for the input image data RGB and generates the data signal DATA based on the driving mode signal. The timing controller 200 outputs the data signal DATA to the data driver 500 .
[0091] The data signal DATA includes a left data signal and a right data signal in the 3D mode. According to an embodiment, the data signal DATA further includes a black data signal inserted between the left data signal and the right data signal in the 3D mode.
[0092] The timing controller 200 generates the third control signal CONT 3 for controlling an operation of the gamma reference voltage generator 400 based on the input control signal CONT and outputs the third control signal CONT 3 to the gamma reference voltage generator 400 . The third control signal CONT 3 includes the driving mode signal.
[0093] The gate driver 300 generates gate signals driving the gate lines GL in response to the first control signal CONT 1 received from the timing controller 200 . The gate driver 300 sequentially outputs the gate signals to the gate lines GL.
[0094] The gate driver 300 is directly mounted on the display panel 100 or connected to the display panel 100 in a tape carrier package (TCP) type. Alternatively, the gate driver 300 is integrated on the display panel 100 .
[0095] The gamma reference voltage generator 400 generates a gamma reference voltage VGREF in response to the third control signal CONT 3 received from the timing controller 200 . The gamma reference voltage generator 400 provides the gamma reference voltage VGREF to the data driver 500 . The gamma reference voltage VGREF has a value corresponding to a level of the data signal DATA.
[0096] According to an embodiment, the gamma reference voltage generator 400 generates gamma reference voltages VGREF which are different from each other with respect to the same grayscale data according to the driving mode.
[0097] According to an embodiment, the gamma reference voltage generator 400 is disposed in the timing controller 200 or in the data driver 500 .
[0098] The data driver 500 receives the second control signal CONT 2 and the data signal DATA from the timing controller 200 , and receives the gamma reference voltages VGREF from the gamma reference voltage generator 400 . The data driver 500 converts the data signal DATA into analog data voltages using the gamma reference voltages VGREF. The data driver 500 sequentially outputs the data voltages to the data lines DL.
[0099] The data driver 500 includes a shift register (not shown), a latch (not shown), a signal processing part (not shown) and a buffer part (not shown). The shift register outputs a latch pulse to the latch. The latch temporally stores the data signal DATA. The latch outputs the data signal DATA to the signal processing part. The signal processing part generates an analog data voltage based on the digital data signal and the gamma reference voltage VGREF. The signal processing part outputs the data voltage to the buffer part. The buffer part compensates for the data voltage to have a uniform level. The buffer part outputs the compensated data voltage to the data line DL.
[0100] According to an embodiment, the data driver 500 is directly mounted on the display panel 100 or connected to the display panel 100 in a TCP type. Alternatively, the data driver 500 is integrated on the display panel 100 .
[0101] The display apparatus further includes a liquid crystal lens (not shown) on the display panel 100 . The liquid crystal lens transmits images from the display panel 100 without refraction in the 2D mode. The liquid crystal lens refracts images from the display panel 100 and provides a first viewpoint image to a first viewpoint and a second viewpoint image to a second viewpoint in the 3D mode. For example, according to an embodiment, the first viewpoint image includes a left image. A viewer's left eye corresponds to the first viewpoint. The second viewpoint image includes a right image. The viewer's right eye corresponds to the second viewpoint.
[0102] Alternatively, the display apparatus further includes a liquid crystal barrier (not shown) on the display panel 100 . The liquid crystal barrier transmits images from the display panel 100 without blocking in the 2D mode. The liquid crystal barrier selectively blocks images from the display panel 100 and provides the first viewpoint image to the first viewpoint and the second viewpoint image to the second viewpoint in the 3D mode.
[0103] Alternatively, the display apparatus temporally divides images of the display panel 100 into left images and right images. The viewer wears shutter glasses selectively transmitting the left images to his/her left eye and the right images to his/her right eye.
[0104] Alternatively, the display apparatus further includes a polarizing element (not shown) that polarizes images and generates the left images and the right images in the 3D mode. The polarizing element is disposed on the display panel 100 . The polarizing element causes light transmitted through a first unit pixel and light transmitted through a second unit pixel to have different directions from each other. For example, according to an embodiment, a left image is left-circularly polarized and the right image is right-circularly polarized. As a consequence, the viewer receives 3D images using polarizing glasses selectively transmitting the left-circularly polarized image and the right-circularly polarized image.
[0105] FIG. 2 is a circuit diagram illustrating a unit pixel included in the display apparatus of FIG. 1 .
[0106] Referring to FIG. 2 , the unit pixel includes a first subpixel and a second subpixel. The first subpixel includes a high pixel. The second subpixel includes a low pixel.
[0107] In the 2D mode, a first voltage is charged to the first subpixel and a second voltage is charged to the second subpixel. The second voltage is different from the first voltage for at least one grayscale. For example, according to an embodiment, the first voltage is greater than the second voltage.
[0108] In the 3D mode, a third voltage is charged to the first subpixel and a fourth voltage is charged to the second subpixel. The fourth voltage is the same or substantially equal to the third voltage. For example, according to an embodiment, the third and fourth voltages are the same or substantially equal to one of the first and second voltages.
[0109] The first subpixel includes a first switching element TFTH 1 , a first liquid crystal capacitor CLCH 1 and a first storage capacitor CSTH 1 . The second subpixel includes a second switching element TFTL 1 , a second liquid crystal capacitor CLCL 1 and a second storage capacitor CSTL 1 . The second subpixel is adjacent to the first subpixel in an extending direction of the data line DL.
[0110] The first switching element TFTH 1 is connected to an N-th gate line GLN and an M-th data line DLM. A gate electrode of the first switching element TFTH 1 is connected to the N-th gate line GLN. A source electrode of the first switching element TFTH 1 is connected to the M-th data line DLM. A drain electrode of the first switching element TFTH 1 is connected to a first end of the first liquid crystal capacitor CLCH 1 and a first end of the first storage capacitor CSTH 1 . A first pixel electrode is disposed at the first end of the first liquid crystal capacitor CLCH 1 . A common voltage VCOM is applied to a second end of the first liquid crystal capacitor CLCH 1 opposite to the first end of the first liquid crystal capacitor CLCH 1 through a common electrode. A storage voltage VCST is applied to a second end of the first storage capacitor CSTH 1 opposite to the first end of the first storage capacitor CSTH 1 . For example, according to an embodiment, the common voltage VCOM is the same or substantially equal to the storage voltage VCST.
[0111] The second switching element TFTL 1 is connected to an (N+1)-th gate line GLN+1 adjacent to the N-th gate line GLN and the M-th data line DLM. A gate electrode of the second switching element TFTL 1 is connected to the (N+1)-th gate line GLN+1. A source electrode of the second switching element TFTL 1 is connected to the M-th data line DLM. A drain electrode of the second switching element TFTL 1 is connected to a first end of the second liquid crystal capacitor CLCL 1 and a first end of the second storage capacitor CSTL 1 . A second pixel electrode is disposed at the first end of the second liquid crystal capacitor CLCL 1 . A common voltage VCOM is applied to a second end of the second liquid crystal capacitor CLCL 1 opposite to the first end of the second liquid crystal capacitor CLCL 1 through the common electrode. A storage voltage VCST is applied to a second end of the second storage capacitor CSTL 1 opposite to the first end of the second storage capacitor CSTL 1 . In an exemplary embodiment, at least one of the first and second storage capacitors CSTH 1 and CSTL 1 may be omitted.
[0112] FIG. 3 is a conceptual diagram illustrating a lookup table referred to by the timing controller 200 of FIG. 1 .
[0113] The timing controller 200 includes a driving mode determining part (not shown), a control signal generating part (not shown), a data compensating part (not shown) and a grayscale data converting part (not shown). The timing controller 200 may be logically divided into the driving mode determining part, the control signal generating part, the data compensating part and the grayscale data converting part.
[0114] The driving mode determining part determines whether the driving mode is the 2D mode or the 3D mode. The driving mode determining part determines the driving mode based on a driving mode signal inputted from an outside source. Alternatively, the driving mode determining part determines the driving mode based on the input image data RGB.
[0115] The control signal generating part generates the first control signal CONT 1 based on the input control signal CONT and outputs the first control signal CONT 1 to the gate driver 300 . The control signal generating part generates the second control signal CONT 2 based on the input control signal CONT and outputs the second control signal CONT 2 to the data driver 500 . The control signal generating part generates the third control signal CONT 3 based on the input control signal CONT and outputs the third control signal CONT 3 to the gamma reference voltage generator 400 .
[0116] The data compensating part receives input image data RGB from an outside source. The data compensating part compensates for the input image data RGB and generates the data signal DATA.
[0117] The data compensating part includes an adaptive color correction part (not shown) and a dynamic capacitance compensating part (not shown).
[0118] The adaptive color correction part receives the input image data RGB and performs an adaptive color correction (“ACC”) process. The adaptive color correction part compensates for the input image data RGB using a gamma curve.
[0119] The dynamic capacitance compensating part performs a dynamic capacitance compensation (“DCC”) process that compensates for grayscales of present frame data using previous frame data and the present frame data.
[0120] The grayscale data converting part converts a grayscale of the input image data based on the driving mode. The grayscale data converting part outputs the converted grayscale data to the data driver 500 . The grayscale of the input image data includes grayscale data of the data signal DATA. The grayscale data converting part refers to the lookup table of FIG. 3 .
[0121] The lookup table of FIG. 3 has columns respectively representing the grayscales GRAY of the input image data, first grayscale data GRAYH and second grayscale data GRAYL.
[0122] In the 2D mode, the grayscale data converting part converts the grayscales GRAY of the input image data into the first grayscale data GRAYH corresponding to the first subpixel and the second grayscale data GRAYL corresponding to the second subpixel.
[0123] For example, according to an embodiment, when the driving mode is the 2D mode and the grayscale GRAY of the input image data is 1, the grayscale data converting part sets the first grayscale data GRAYH as GRAYH 1 corresponding to the first subpixel and the second grayscale data GRAYL as GRAYL 1 corresponding to the second subpixel.
[0124] In an exemplary embodiment, when the grayscale data converting part converts all of the grayscales GRAY of the input image data into the first grayscale data GRAYH and the second grayscale data GRAYL, the first grayscale data GRAYH have the same or substantially the same values as the second grayscale data GRAYL for some of the grayscales. For example, according to an embodiment, when the grayscale data converting part converts 256 grayscales of the input image data into the first grayscale data GRAYH and the second grayscale data GRAYL, some of the 256 values of the first grayscale data GRAYH are the same or substantially the same as some of the 256 values of the second grayscale data GRAYH with respect to the same grayscales of the input image data.
[0125] The grayscale data converting part outputs the converted first and second grayscale data GRAYH and GRAYL to the data driver 500 . In the 2D mode, the data driver 500 provides a data voltage corresponding to the first grayscale data GRAYH to the first subpixel and a data voltage corresponding to the second grayscale data GRAYL to the second subpixel using the gamma reference voltage generator 400 . As a result, the data voltage charged to the first subpixel is different from the data voltage charged to the second subpixel for at least one grayscale.
[0126] In the 3D mode, the grayscale data converting part does not convert the grayscales GRAY of the input image data.
[0127] As a consequence, when the driving mode is the 3D mode and the grayscale GRAY of the input image data is 1, the first grayscale data corresponding to the first subpixel is 1 and the second grayscale data corresponding to the second subpixel is 1.
[0128] The grayscale data converting part outputs the grayscale GRAY of the input image data to the gate driver 500 . In the 3D mode, the data driver 500 provides a data voltage corresponding to the grayscale GRAY of the input image data to the first subpixel and a data voltage corresponding to the grayscale GRAY of the input image data to the second subpixel using the gamma reference voltage generator 400 . As a result, the data voltage charged to the first subpixel is the same or substantially the same as the data voltage charged to the second subpixel.
[0129] According to an embodiment, the timing controller 200 further includes a memory (not shown). The lookup table is stored in the memory. According to an embodiment, the memory is disposed in the timing controller 200 . Alternatively, the memory is disposed out of the timing controller 200 .
[0130] According to an exemplary embodiment, a data voltage charged to the first subpixel is different from a data voltage charged to the second subpixel in the 2D mode so that side visibility may be improved. The data voltage charged to the first subpixel is the same or substantially the same as the data voltage charged to the second subpixel in the 3D mode so that moiré may be prevented and the luminance of images may be improved. As a consequence, display quality may be improved when the display panel displays 2D images and 3D images.
[0131] FIG. 4 is a conceptual diagram illustrating a lookup table referred to by a timing controller of a display apparatus according to an exemplary embodiment of the present invention.
[0132] The display apparatus is the same or substantially the same as the display apparatus described in connection with FIGS. 1 to 3 except for the lookup table referred to by the timing controller.
[0133] Referring to FIG. 4 , the lookup table of FIG. 4 has columns respectively representing grayscales GRAY of the input image data and second grayscale data GRAYL.
[0134] In the 2D mode, the grayscale data converting part converts the grayscale GRAY of the input image data into the second grayscale data GRAYL corresponding to the second subpixel.
[0135] For example, according to an embodiment, when the driving mode is the 2D mode and the grayscale GRAY of the input image data is 1, the grayscale data converting part sets the second grayscale data GRAYL as GRAYL 1 corresponding to the second subpixel.
[0136] The grayscale data converting part outputs the grayscale GRAY of the input image data and converted second grayscale data GRAYL to the data driver 500 . In the 2D mode, the data driver 500 provides a data voltage corresponding to the grayscale GRAY of the input image data to the first subpixel and a data voltage corresponding to the second grayscale data GRAYL to the second subpixel using the gamma reference voltage generator 400 . As a result, the data voltage charged to the first subpixel is different from the data voltage charged to the second subpixel for at least one grayscale.
[0137] In the 3D mode, the grayscale data converting part does not convert the grayscale GRAY of the input image data.
[0138] As a consequence, when the driving mode is the 3D mode and the grayscale GRAY of the input image data is 1, the first grayscale data corresponding to the first subpixel is 1 and the second grayscale data corresponding to the second subpixel is 1.
[0139] The grayscale data converting part outputs the grayscale GRAY of the input image data to the gate driver 500 . In the 3D mode, the data driver 500 provides a data voltage corresponding to the grayscale GRAY of the input image data to the first subpixel and a data voltage corresponding to the grayscale GRAY of the input image data to the second subpixel using the gamma reference voltage generator 400 . As a result, the data voltage charged to the first subpixel is the same or substantially the same as the data voltage charged to the second subpixel.
[0140] According to an exemplary embodiment, a data voltage charged to the first subpixel is different from a data voltage charged to the second subpixel in the 2D mode so that side visibility may be improved. The data voltage charged to the first subpixel is the same or substantially the same as the data voltage charged to the second subpixel in the 3D mode so that moiré may be prevented and the luminance of images may be improved. As a consequence, display quality may be improved when the display panel displays 2D images and 3D images.
[0141] The grayscale of the input image data is used as grayscale data for the first subpixel so that the capacity of the lookup table may be decreased.
[0142] FIG. 5 is a circuit diagram illustrating a unit pixel of a display apparatus according to an exemplary embodiment of the present invention.
[0143] The display apparatus is the same or substantially the same as the display apparatus described in connection with FIGS. 1 to 3 except for the structure of the unit pixel.
[0144] Referring to FIG. 5 , the unit pixel includes a first subpixel and a second subpixel. The first subpixel is a high pixel. The second subpixel is a low pixel.
[0145] In the 2D mode, a first voltage is charged to the first subpixel and a second voltage is charged to the second subpixel. The second voltage is different from the first voltage for at least one grayscale. For example, according to an embodiment, the first voltage is greater than the second voltage.
[0146] In the 3D mode, a third voltage is charged to the first subpixel and a fourth voltage is charged to the second subpixel. The fourth voltage is the same or substantially equal to the third voltage. For example, according to an embodiment, the third and fourth voltages are the same or substantially equal to one of the first and second voltages.
[0147] The first subpixel includes a first switching element TFTH 2 , a first liquid crystal capacitor CLCH 2 and a first storage capacitor CSTH 2 . The second subpixel includes a second switching element TFTL 2 , a second liquid crystal capacitor CLCL 2 and a second storage capacitor CSTL 2 . The second subpixel is adjacent to the first subpixel in an extending direction of the data line DL.
[0148] The first switching element TFTH 2 is connected to an N-th gate line GLN and an M-th data line DLM. A gate electrode of the first switching element TFTH 2 is connected to the N-th gate line GLN. A source electrode of the first switching element TFTH 2 is connected to the M-th data line DLM. A drain electrode of the first switching element TFTH 2 is connected to a first end of the first liquid crystal capacitor CLCH 2 and a first end of the first storage capacitor CSTH 2 . A first pixel electrode is disposed at the first end of the first liquid crystal capacitor CLCH 2 . A common voltage VCOM is applied to a second end of the first liquid crystal capacitor CLCH 2 opposite to the first end of the first liquid crystal capacitor CLCH 2 through the common electrode. A storage voltage VCST is applied to a second end of the first storage capacitor CSTH 2 opposite to the first end of the first storage capacitor CSTH 2 . For example, according to an embodiment, the common voltage VCOM is the same or substantially equal to the storage voltage VCST.
[0149] The second switching element TFTL 2 is connected to the N-th gate line GLN and an (M+1)-th data line DLM+1 adjacent to the M-th data line DLM. A gate electrode of the second switching element TFTL 2 is connected to the N-th gate line GLN. A source electrode of the second switching element TFTL 2 is connected to the (M+1)-th data line DLM+1. A drain electrode of the second switching element TFTL 2 is connected to a first end of the second liquid crystal capacitor CLCL 2 and a first end of the second storage capacitor CSTL 2 . A second pixel electrode is disposed at the first end of the second liquid crystal capacitor CLCL 2 . A common voltage VCOM is applied to a second end of the second liquid crystal capacitor CLCL 2 opposite to the first end of the second liquid crystal capacitor CLCL 2 through the common electrode. A storage voltage VCST is applied to a second end of the second storage capacitor CSTL 2 opposite to the first end of the second storage capacitor CSTL 2 . In an exemplary embodiment, at least one of the first and second storage capacitors CSTH 2 and CSTL 2 is omitted.
[0150] The lookup tables of FIGS. 3 and 4 are employed in the display apparatus described in connection with FIG. 5 .
[0151] According to an exemplary embodiment, a data voltage charged to the first subpixel is different from a data voltage charged to the second subpixel in the 2D mode so that side visibility may be improved. The data voltage charged to the first subpixel is the same or substantially the same as the data voltage charged to the second subpixel in the 3D mode so that moiré may be prevented and the luminance of image may be improved. As a consequence, display quality may be improved when the display panel displays 2D images and 3D images.
[0152] FIG. 6 is a conceptual diagram illustrating a connecting structure between an output part of a data driver and a unit pixel of a display apparatus according to an exemplary embodiment of the present invention.
[0153] The display apparatus is the same or substantially the same as the display apparatus described in connection with FIG. 5 except that the data driver 500 outputs the same data voltage regardless of the driving mode and the output part of the data driver 500 includes a switching part.
[0154] The data driver 500 of the display apparatus outputs a first voltage to the first subpixel and a second voltage to the second subpixel regardless of the driving mode. The second voltage is different from the first voltage for at least one grayscale. The unit pixel of FIG. 5 is applied to the display apparatus described in connection with FIG. 6 .
[0155] Referring to FIGS. 5 and 6 , a first switch SW 1 is disposed between a first output buffer O 1 of the data driver 500 and the M-th data line DLM. A second switch SW 2 is disposed between a second output buffer O 2 of the data driver 500 and the (M+1)-th data line DLM+1. A third switch SW 3 is disposed between the M-th data line DLM and the (M+1)-th data line DLM+1.
[0156] In the 2D mode, the first and second switches SW 1 and SW 2 are turned on and the third switch SW 3 is turned off. Thus, the first voltage is charged to the first subpixel connected to the M-th data line DLM. The second voltage is charged to the second subpixel connected to the (M+1)-th data line DLM+1.
[0157] In the 3D mode, the first and third switches SW 1 and SW 3 are turned on and the second switch SW 2 is turned off. Thus, the first voltage is charged to the first subpixel connected to the M-th data line DLM and the second subpixel connected to the (M+1)-th data line DLM+1.
[0158] According to an exemplary embodiment, a data voltage charged to the first subpixel is different from a data voltage charged to the second subpixel in the 2D mode so that side visibility may be improved. The data voltage charged to the first subpixel is the same or substantially the same as the data voltage charged to the second subpixel in the 3D mode so that moiré may be prevented and the luminance of images may be improved. As a consequence, display quality may be improved when the display panel displays 2D images and 3D images.
[0159] FIG. 7 is a circuit diagram illustrating a unit pixel of a display apparatus according to an exemplary embodiment of the present invention;
[0160] The display apparatus is the same or substantially the same as the display apparatus described in connection with FIGS. 1 to 3 except for the structure of the unit pixel.
[0161] Referring to FIG. 7 , the unit pixel includes a first subpixel and a second subpixel. The first subpixel is a high pixel. The second subpixel is a low pixel.
[0162] The first subpixel includes a first switching element TFTH 3 , a first liquid crystal capacitor CLCH 3 and a first storage capacitor CSTH 3 . The second subpixel includes a second switching element TFTL 3 , a second liquid crystal capacitor CLCL 3 , a second storage capacitor CSTL 3 , a third switching element TFTCS and a down capacitor CDOWN.
[0163] The first switching element TFTH 3 is connected to an N-th gate line GLN, an M-th data line DLM and a first pixel electrode. A gate electrode of the first switching element TFTH 3 is connected to the N-th gate line GLN. A source electrode of the first switching element TFTH 3 is connected to the M-th data line DLM. A drain electrode of the first switching element TFTH 3 is connected to a first end of the first liquid crystal capacitor CLCH 3 and a first end of the first storage capacitor CSTH 3 . The first pixel electrode is disposed at the first end of the first liquid crystal capacitor CLCH 3 . A common voltage VCOM is applied to a second end of the first liquid crystal capacitor CLCH 3 opposite to the first end of the first liquid crystal capacitor CLCH 3 through the common electrode. A storage voltage VCST is applied to a second end of the first storage capacitor CSTH 3 opposite to the first end of the first storage capacitor CSTH 3 . For example, according to an embodiment, the common voltage VCOM is the same or substantially equal to the storage voltage VCST.
[0164] The second switching element TFTL 3 is connected to the N-th gate line GLN and the M-th data line DLM and a second pixel electrode. A gate electrode of the second switching element TFTL 3 is connected to the N-th gate line GLN. A source electrode of the second switching element TFTL 3 is connected to the M-th data line DLM. A drain electrode of the second switching element TFTL 3 is connected to a first end of the second liquid crystal capacitor CLCL 3 and a first end of the second storage capacitor CSTL 3 . The second pixel electrode is disposed at the first end of the second liquid crystal capacitor CLCL 3 . A common voltage VCOM is applied to a second end of the second liquid crystal capacitor CLCL 3 opposite to the first end of the second liquid crystal capacitor CLCL 3 through the common electrode. A storage voltage VCST is applied to a second end of the second storage capacitor CSTL 3 opposite to the first end of the second storage capacitor CSTL 3 .
[0165] A gate electrode of the third transistor TFTCS is connected to an N-th control line CLN. A source electrode of the third transistor TFTCS is connected to a second end of the down capacitor CDOWN. The storage voltage VCST is applied to a first end of the down capacitor CDOWN opposite to the second end of the down capacitor CDOWN. A drain electrode of the third transistor TFTCS is connected to the first end of the second liquid crystal capacitor CLCL 3 and the first end of the second storage capacitor CSTL 3 . In an exemplary embodiment, at least one of the first and second storage capacitors CSTH 3 and CSTL 3 is omitted.
[0166] FIG. 8 is a conceptual diagram illustrating a connecting structure between an output part of a gate driver and the unit pixel of FIG. 7 .
[0167] Referring to FIG. 8 , the N-th control line CLN is connected to a fourth switch SW 4 which is operated according to a driving mode signal MODE. An N-th control signal CN controlling the N-th control line CLN and a gate off voltage VOFF turning off the switching element are selectively applied to the N-th control line CLN according to the driving mode signal MODE. The N-th control signal CN includes a gate on voltage and a gate off voltage. The N-th control signal CN has a gate on voltage, which is at a high level, after a gate on voltage of a gate signal is applied to the N-th gate line GLN. According to an embodiment, the N-th control signal CN has the same phase as an (N+K)-th gate signal. The N-th control line CLN is connected to an (N+K)-th gate line through the fourth switch SW 4 . For example, according to an embodiment, the (N+K)-th gate line is the (N+1)-th gate line GLN+1.
[0168] In the 2D mode, the N-th control signal CN is applied to the N-th control line CLN.
[0169] When a gate on voltage of the N-th gate signal GN is applied to the N-th gate line GLN, the first and second switching elements TFTH 3 and TFTL 3 are turned on so that a first voltage is applied to the first subpixel and the second subpixel.
[0170] After the gate on voltage of the N-th gate signal GN is applied to the N-th gate line GLN, the gate on voltage of the N-th control signal CN is applied to the N-th control signal CLN so that the third switching element TFTCS is turned on. When the third switching element TFTCS is turned on, a level of the first voltage applied to the second subpixel is decreased due to the down capacitor CDOWN and the storage voltage VCST. As a result, a data voltage charged to the first subpixel is different from a data voltage charged to the second subpixel for at least one grayscale. As shown in FIG. 8 , the N-th control signal CN is applied to the N-th control line CLN through the fourth switch SW 4 . In an exemplary embodiment, the N-th control line CNL is connected to the (N+K)-th gate line through the fourth switch SW 4 to apply the (N+K)-th gate signal to the gate electrode of the third switching element TFTCS. For example, according to an embodiment, N+K is N+1.
[0171] In the 3D mode, the gate off voltage of the N-th control signal CN is applied to the N-th control line CLN.
[0172] When a gate on voltage of the N-th gate signal GN is applied to the N-th gate line GLN, the first and second switching elements TFTH 3 and TFTL 3 are turned on so that a first voltage is applied to the first subpixel and the second subpixel.
[0173] After the gate on voltage of the N-th gate signal GN is applied to the N-th gate line GLN, the gate off voltage VOFF of the N-th control signal CN is applied to the N-th control signal CLN so that the third switching element TFTCS is turned off. As a result, the first voltage is charged to the first subpixel and the second subpixel.
[0174] According to an exemplary embodiment, a data voltage charged to the first subpixel is different from a data voltage charged to the second subpixel in the 2D mode so that side visibility may be improved. The data voltage charged to the first subpixel is the same or substantially the same as the data voltage charged to the second subpixel in the 3D mode so that moiré may be prevented and the luminance of images may be improved. As a consequence, display quality may be improved when the display panel displays 2D images and 3D images.
[0175] FIG. 9 is a block diagram illustrating a display apparatus according to an exemplary embodiment of the present invention.
[0176] The display apparatus is the same or substantially the same as the display apparatus described in connection with FIGS. 1 to 3 except for a storage voltage generator 600 and the structure of the unit pixel.
[0177] Referring to FIG. 9 , the display apparatus includes a display panel 100 and a panel driver. The panel driver includes a timing controller 200 , a gate driver 300 , a gamma reference voltage generator 400 , a data driver 500 and a storage voltage generator 600 .
[0178] The timing controller 200 generates a first control signal CONT 1 , a second control signal CONT 2 , a third control signal CONT 3 , a fourth control signal CONT 4 and a data signal DATA based on input image data RGB and an input control signal CONT.
[0179] The timing controller 200 generates the fourth control signal CONT 4 for controlling an operation of the storage voltage generator 600 based on the input control signal CONT and outputs the fourth control signal CONT 4 to the storage voltage generator 600 . The fourth control signal CONT 4 includes a driving mode signal.
[0180] The storage voltage generator 600 generates storage voltages which vary according to the driving mode. The storage voltage generator 600 is described in detail referring to FIGS. 11 and 12 .
[0181] FIG. 10 is a circuit diagram illustrating a unit pixel included in the display apparatus of FIG. 9 .
[0182] Referring to FIG. 10 , the unit pixel includes a first subpixel and a second subpixel. The first subpixel is a high pixel. The second subpixel is a low pixel.
[0183] The first subpixel includes a first switching element TFTH 4 , a first liquid crystal capacitor CLCH 4 and a first storage capacitor CSTH 4 . The second subpixel includes a second switching element TFTL 4 , a second liquid crystal capacitor CLCL 4 and a second storage capacitor CSTL 4 .
[0184] The first switching element TFTH 4 is connected to an N-th gate line GLN, an M-th data line DLM and a first pixel electrode. A gate electrode of the first switching element TFTH 4 is connected to the N-th gate line GLN. A source electrode of the first switching element TFTH 4 is connected to the M-th data line DLM. A drain electrode of the first switching element TFTH 4 is connected to a first end of the first liquid crystal capacitor CLCH 4 and a first end of the first storage capacitor CSTH 4 . The first pixel electrode is disposed at the first end of the first liquid crystal capacitor CLCH 4 . A common voltage VCOM is applied to a second end of the first liquid crystal capacitor CLCH 4 opposite to the first end of the first liquid crystal capacitor CLCH 4 through the common electrode. A second end of the first storage capacitor CSTH 4 opposite to the first end of the first storage capacitor CSTH 4 is connected to a first storage voltage line VCSTL 1 and receives a first storage voltage VCST 1 .
[0185] The second switching element TFTL 4 is connected to the N-th gate line GLN and the M-th data line DLM and a second pixel electrode. A gate electrode of the second switching element TFTL 4 is connected to the N-th gate line GLN. A source electrode of the second switching element TFTL 4 is connected to the M-th data line DLM. A drain electrode of the second switching element TFTL 4 is connected to a first end of the second liquid crystal capacitor CLCL 4 and a first end of the second storage capacitor CSTL 4 . The second pixel electrode is disposed at the first end of the second liquid crystal capacitor CLCL 4 . A common voltage VCOM is applied to a second end of the second liquid crystal capacitor CLCL 4 opposite to the first end of the second liquid crystal capacitor CLCL 4 through the common electrode. A second end of the second storage capacitor CSTL 4 opposite to the first end of the second storage capacitor CSTL 4 is connected to a second storage voltage line VCSTL 2 and receives a second storage voltage VCST 2 .
[0186] FIG. 11 is a block diagram illustrating the storage voltage generator 600 of FIG. 9 . FIG. 12 is a waveform diagram illustrating signals applied to the unit pixel of FIG. 9 .
[0187] Referring to FIGS. 10 to 12 , the storage voltage generator 600 includes a first storage voltage generating part 610 , a second storage voltage generating part 620 , and a fifth switch SW 5 .
[0188] The first storage voltage generating part 610 generates the first storage voltage VCST 1 applied to the first storage voltage line VCSTL 1 and the second storage voltage VCST 2 applied to the second storage voltage line VCSTL 2 in the 2D mode.
[0189] The first and second storage voltages VCST 1 and VCST 2 are alternating-current (“AC”) voltages. The first and second storage voltages VCST 1 and VCST 2 periodically increase and decrease. For example, according to an embodiment, the first and second storage voltages VCST 1 and VCST 2 have square waves. For example, according to an embodiment, peak to peak amplitudes of the first and second storage voltages VCST 1 and VCST 2 are ΔVC 1 .
[0190] The first storage voltage VCST 1 has a phase different from a phase of the second storage voltage VCST 2 . The first storage voltage VCST 1 has a waveform opposite to the second storage voltage VCST 2 . For example, according to an embodiment, a rising edge of the first storage voltage VCST 1 is the same or substantially the same as a falling edge of the second storage voltage VCST 2 . A falling edge of the first storage voltage VCST 1 is the same or substantially the same as a rising edge of the second storage voltage VCST 2 .
[0191] The second storage voltage generating part 620 generates a third storage voltage VCST 3 applied to the first storage voltage line VCSTL 1 and a fourth storage voltage VCST 4 applied to the second storage voltage line VCSTL 2 in the 3D mode.
[0192] The third and fourth storage voltages VCST 3 and VCST 4 are AC voltages. The third and fourth storage voltages VCST 3 and VCST 4 periodically increase and decrease. For example, according to an embodiment, the third and fourth storage voltages VCST 3 and VCST 4 have square waves. For example, according to an embodiment, peak to peak amplitudes of the third and fourth storage voltages VCST 3 and VCST 4 are ΔVC 2 .
[0193] The third storage voltage VCST 3 has a phase different from a phase of the fourth storage voltage VCST 4 . The third storage voltage VCST 3 has a waveform opposite to the fourth storage voltage VCST 4 . For example, according to an embodiment, a rising edge of the third storage voltage VCST 3 is the same or substantially the same as a falling edge of the fourth storage voltage VCST 4 . A falling edge of the third storage voltage VCST 3 is the same or substantially the same as a rising edge of the fourth storage voltage VCST 4 .
[0194] An amplitude of the third storage voltage VCST 3 in the 3D mode is smaller than an amplitude of the first storage voltage VCST 1 in the 2D mode. For example, according to an embodiment, the amplitude of the third storage voltage VCST 3 is close to 0.
[0195] The fifth switch SW 5 is selectively connected to an output part of the first storage voltage generating part 610 and an output part of the second storage voltage generating part 620 .
[0196] In the 2D mode, the fifth switch SW 5 is connected to the output part of the first storage voltage generating part 610 . When a gate on voltage of the N-th gate signal GN is applied to the N-th gate line GLN, the first and second switching elements TFTH 4 and TFTL 4 are turned on so that a first voltage is applied to the first subpixel and the second subpixel.
[0197] After a gate off voltage of the N-th gate signal GN is applied to the N-th gate line GLN, the first storage voltage VCST 1 rises so that the first voltage charged to the first subpixel increases due to the first storage capacitor CSTH 4 . An increase of the first voltage is determined as following Equation 1.
[0000]
Δ
V
1
=
Δ
VC
1
×
C
S
T
H
C
S
T
H
+
C
L
C
H
+
Cgs
[
Equation
1
]
[0198] Here, ΔV 1 is an increase of the first voltage V 1 , ΔVC 1 is the peak to peak amplitude of the first storage voltage VCST 1 , CSTH is a capacitance of the first storage capacitor CSTH 4 , CLCH is a capacitance of the first liquid crystal capacitor CLCH 4 , and Cgs is a parasitic capacitance between the gate electrode and the source electrode of the first switching element TFTH 4 .
[0199] After the gate off voltage of the N-th gate signal GN is applied to the N-th gate line GLN, the second storage voltage VCST 2 falls so that the first voltage charged to the second subpixel decreases due to the second storage capacitor CSTL 4 . As a result, the voltage charged to the first subpixel is different from the voltage charged to the second subpixel for at least one grayscale.
[0200] In the 3D mode, the fifth switch SW 5 is connected to the output part of the second storage voltage generating part 620 . When the gate on voltage of the N-th gate signal GN is applied to the N-th gate line GLN, the first and second switching elements TFTH 4 and TFTL 4 are turned on so that a first voltage is applied to the first subpixel and the second subpixel.
[0201] After the gate off voltage of the N-th gate signal GN is applied to the N-th gate line GLN, the third storage voltage VCST 3 rises so that the first voltage charged to the first subpixel increases due to the first storage capacitor CSTH 4 . However, the amplitude of the VCST 3 is close to 0 so that the first voltage charged to the first subpixel does not change substantially.
[0202] After the gate off voltage of the N-th gate signal GN is applied to the N-th gate line GLN, the fourth storage voltage VCST 4 falls so that the first voltage charged to the second subpixel decreases due to the second storage capacitor CSTL 4 . However, the amplitude of the VCST 4 is close to 0 so that the first voltage charged to the second subpixel does not change substantially. As a result, the voltage charged to the first subpixel is the same or substantially the same as the voltage charged to the second subpixel.
[0203] Although it has been described in connection with FIGS. 10 to 12 that the storage voltage generator 600 includes the first storage voltage generating part 610 generating the storage voltages for the 2D mode and the second storage voltage generating part 620 generating the storage voltages for the 3D mode and the fifth switch SW 5 operating according to the driving mode signal MODE, the embodiments of the present invention are not limited thereto. Alternatively, the storage voltage generator 600 includes a single block selectively generating the storage voltages for the 2D mode and the storage voltages for the 3D mode according to the driving mode signal MODE.
[0204] According to an exemplary embodiment, a data voltage charged to the first subpixel is different from a data voltage charged to the second subpixel in the 2D mode so that side visibility may be improved. The data voltage charged to the first subpixel is the same or substantially the same as the data voltage charged to the second subpixel in the 3D mode so that moiré may be prevented and the luminance of images may be improved. As a consequence, display quality may be improved when the display panel displays 2D images and 3D images.
[0205] FIG. 13 is a storage voltage generator of a display apparatus according to an exemplary embodiment of the present invention. FIG. 14 is a waveform diagram illustrating signals applied to a unit pixel of the display apparatus of FIG. 13 .
[0206] The display apparatus is the same or substantially the same as the display apparatus described in connection with FIGS. 9 to 12 except for the structure of the storage voltage generator 600 A.
[0207] Referring to FIGS. 10 , 13 and 14 , the storage voltage generator 600 A includes a first storage voltage generating part 610 , a direct-current (“DC”) storage voltage VDC applying line and a sixth switch SW 6 .
[0208] The first storage voltage generating part 610 generates the first storage voltage VCST 1 applied to the first storage voltage line VCSTL 1 and the second storage voltage VCST 2 applied to the second storage voltage line VCSTL 2 in the 2D mode.
[0209] The first and second storage voltages VCST 1 and VCST 2 are alternating-current (“AC”) voltages. The first and second storage voltages VCST 1 and VCST 2 periodically increase and decrease. For example, according to an embodiment, peak to peak amplitudes of the first and second storage voltages VCST 1 and VCST 2 are ΔVC 1 .
[0210] The first storage voltage VCST 1 has a phase different from a phase of the second storage voltage VCST 2 . The first storage voltage VCST 1 has a waveform opposite to the second storage voltage VCST 2 . For example, according to an embodiment, a rising edge of the first storage voltage VCST 1 is the same or substantially the same as a falling edge of the second storage voltage VCST 2 . A falling edge of the first storage voltage VCST 1 is the same or substantially the same as a rising edge of the second storage voltage VCST 2 .
[0211] The DC storage voltage applying line transmits the DC storage voltage VDC. For example, according to an embodiment, the DC storage voltage VDC is the same or substantially equal to the common voltage VCOM.
[0212] The sixth switch SW 6 is selectively connected to an output part of the first storage voltage generating part 610 and the DC storage voltage applying line.
[0213] In the 2D mode, the sixth switch SW 6 is connected to the output part of the first storage voltage generating part 610 . When a gate on voltage of the N-th gate signal GN is applied to the N-th gate line GLN, the first and second switching elements TFTH 4 and TFTL 4 are turned on so that a first voltage is applied to the first subpixel and the second subpixel.
[0214] After a gate off voltage of the N-th gate signal GN is applied to the N-th gate line GLN, the first storage voltage VCST 1 rises so that the first voltage charged to the first subpixel increases due to the first storage capacitor CSTH 4 .
[0215] After the gate off voltage of the N-th gate signal GN is applied to the N-th gate line GLN, the second storage voltage VCST 2 falls so that the first voltage charged to the second subpixel decreases due to the second storage capacitor CSTL 4 decreases. As a result, a voltage charged to the first subpixel is different from a voltage charged to the second subpixel for at least one grayscale.
[0216] In the 3D mode, the sixth switch SW 6 is connected to the DC voltage applying line. When the gate on voltage of the N-th gate signal GN is applied to the N-th gate line GLN, the first and second switching elements TFTH 4 and TFTL 4 are turned on so that a first voltage is applied to the first subpixel and the second subpixel.
[0217] After the gate off voltage of the N-th gate signal GN is applied to the N-th gate line GLN, the DC storage voltage VDC does not change so that the first voltage charged to the first subpixel maintains a uniform or substantially a uniform level due to the first storage capacitor CSTH 4 .
[0218] After the gate off voltage of the N-th gate signal GN is applied to the N-th gate line GLN, the DC storage voltage VDC does not change so that the first voltage charged to the first subpixel maintains a uniform or a substantially uniform level due to the second storage capacitor CSTL 4 . As a result, a voltage charged to the first subpixel is the same or substantially the same as a voltage charged to the second subpixel.
[0219] According to an exemplary embodiment, a data voltage charged to the first subpixel is different from a data voltage charged to the second subpixel in the 2D mode so that side visibility may be improved. The data voltage charged to the first subpixel is the same or substantially the same as the data voltage charged to the second subpixel in the 3D mode so that moiré may be prevented and the luminance of images may be improved. As a consequence, display quality may be improved when the display panel displays 2D images and 3D images.
[0220] FIG. 15 is a circuit diagram illustrating a unit pixel of a display apparatus according to an exemplary embodiment of the present invention.
[0221] The display apparatus is the same or substantially the same as the display apparatus described in connection with FIGS. 1 to 3 except for the structure of the unit pixel.
[0222] Referring to FIG. 15 , the unit pixel includes a first subpixel and a second subpixel. The first subpixel is a high pixel. The second subpixel is a low pixel.
[0223] In the 2D mode, a first voltage is charged to the first subpixel and a second voltage is charged to the second subpixel. The second voltage is different from the first voltage for at least one grayscale. For example, according to an embodiment, the first voltage is greater than the second voltage.
[0224] In the 3D mode, a third voltage is charged to the first subpixel and a fourth voltage is charged to the second subpixel. The fourth voltage is the same or substantially equal to the third voltage. For example, according to an embodiment, the third and fourth voltages may be the same or substantially equal to one of the first and second voltages.
[0225] The first subpixel includes a first switching element TFTH 5 , a first liquid crystal capacitor CLCH 5 and a first storage capacitor CSTH 5 . The second subpixel includes a second switching element TFTL 5 , a second liquid crystal capacitor CLCL 5 and a second storage capacitor CSTL 5 . The second subpixel is adjacent to the first subpixel in an extending direction of the gate line GL.
[0226] The display apparatus further includes a liquid crystal lens (not shown) disposed on the display panel 100 . The liquid crystal lens transmits images from the display panel 100 without being refracted in the 2D mode. The liquid crystal lens refracts images from the display panel 100 and provides a first viewpoint image to a first viewpoint and a second viewpoint image to a second viewpoint in the 3D mode. For example, according to an embodiment, the liquid crystal lens transmits an image on the first subpixel to the first viewpoint and an image on the second subpixel to the second viewpoint.
[0227] Alternatively, the display apparatus further includes a liquid crystal barrier (not shown) disposed on the display panel 100 . The liquid crystal barrier transmits images from the display panel 100 without being blocked in the 2D mode. The liquid crystal barrier selectively blocks images from the display panel 100 and provides a first viewpoint image to the first viewpoint and a second viewpoint image to the second viewpoint in the 3D mode. For example, according to an embodiment, the liquid crystal barrier transmits an image on the first subpixel to the first viewpoint and an image on the second subpixel to the second viewpoint.
[0228] The first switching element TFTH 5 is connected to an N-th gate line GLN and an M-th data line DLM. A gate electrode of the first switching element TFTH 5 is connected to the N-th gate line GLN. A source electrode of the first switching element TFTH 5 is connected to the M-th data line DLM. A drain electrode of the first switching element TFTH 5 is connected to a first end of the first liquid crystal capacitor CLCH 5 and a first end of the first storage capacitor CSTH 5 . A first pixel electrode is disposed at the first end of the first liquid crystal capacitor CLCH 5 . A common voltage VCOM is applied to a second end of the first liquid crystal capacitor CLCH 5 opposite to the first end of the first liquid crystal capacitor CLCH 5 through the common electrode. A storage voltage VCST is applied to a second end of the first storage capacitor CSTH 5 opposite to the first end of the first storage capacitor CSTH 5 . For example, according to an embodiment, the common voltage VCOM is the same or substantially equal to the storage voltage VCST.
[0229] The second switching element TFTL 5 is connected to an (N+1)-th gate line GLN+1 adjacent to the N-th gate line GLN and the M-th data line DLM. A gate electrode of the second switching element TFTL 5 is connected to the (N+1)-th gate line GLN+1. A source electrode of the second switching element TFTL 5 is connected to the M-th data line DLM. A drain electrode of the second switching element TFTL 5 is connected to a first end of the second liquid crystal capacitor CLCL 5 and a first end of the second storage capacitor CSTL 5 . A second pixel electrode is disposed at the first end of the second liquid crystal capacitor CLCL 5 . A common voltage VCOM is applied to a second end of the second liquid crystal capacitor CLCL 5 opposite to the first end of the second liquid crystal capacitor CLCL 5 through the common electrode. A storage voltage VCST is applied to a second end of the second storage capacitor CSTL 5 opposite to the first end of the second storage capacitor CSTL 5 . In an exemplary embodiment, at least one of the first and second storage capacitors CSTH 5 and CSTL 5 is omitted.
[0230] The lookup tables of FIGS. 3 and 4 are employed in the display apparatus described in connection with FIG. 15 .
[0231] According to an exemplary embodiment, a data voltage charged to the first subpixel is different from a data voltage charged to the second subpixel in the 2D mode so that side visibility may be improved. The data voltage charged to the first subpixel is the same or substantially the same as the data voltage charged to the second subpixel in the 3D mode so that moiré may be prevented and the luminance of images may be improved.
[0232] An image on the first subpixel is transmitted to the first viewpoint and an image on the second subpixel is transmitted to the second viewpoint in the 3D mode so that the resolution of 3D images may be prevented from decreasing. As a consequence, display quality may be improved when the display panel displays 2D images and 3D images.
[0233] FIG. 16 is a circuit diagram illustrating a unit pixel of a display apparatus according to an exemplary embodiment of the present invention.
[0234] The display apparatus is the same or substantially the same as the display apparatus described in connection with FIGS. 1 to 3 except for the structure of the unit pixel.
[0235] Referring to FIG. 16 , the unit pixel includes a first subpixel and a second subpixel. The first subpixel is a high pixel. The second subpixel is a low pixel.
[0236] In the 2D mode, a first voltage is charged to the first subpixel and a second voltage is charged to the second subpixel. The second voltage is different from the first voltage for at least one grayscale. For example, according to an embodiment, the first voltage is greater than the second voltage.
[0237] In the 3D mode, a third voltage is charged to the first subpixel and a fourth voltage is charged to the second subpixel. The fourth voltage is the same or substantially equal to the third voltage. For example, according to an embodiment, the third and fourth voltages are the same or substantially equal to one of the first and second voltages.
[0238] The first subpixel includes a first switching element TFTH 6 , a first liquid crystal capacitor CLCH 6 and a first storage capacitor CSTH 6 . The second subpixel includes a second switching element TFTL 6 , a second liquid crystal capacitor CLCL 6 and a second storage capacitor CSTL 6 . The second subpixel is adjacent to the first subpixel in an extending direction of the data line DL.
[0239] The display apparatus further includes a liquid crystal lens (not shown) disposed on the display panel 100 . The liquid crystal lens transmits images from the display panel 100 without being refracted in the 2D mode. The liquid crystal lens refracts images from the display panel 100 and provides a first viewpoint image to a first viewpoint and a second viewpoint image to a second viewpoint in the 3D mode. For example, according to an embodiment, the liquid crystal lens transmits an image on the first subpixel to the first viewpoint and an image on the second subpixel to the second viewpoint.
[0240] Alternatively, the display apparatus further includes a liquid crystal barrier (not shown) disposed on the display panel 100 . The liquid crystal barrier transmits images from the display panel 100 without being blocked in the 2D mode. The liquid crystal barrier selectively blocks images from the display panel 100 and provides a first viewpoint image to the first viewpoint and a second viewpoint image to the second viewpoint in the 3D mode. For example, according to an embodiment, the liquid crystal barrier transmits an image on the first subpixel to the first viewpoint and an image on the second subpixel to the second viewpoint.
[0241] The first switching element TFTH 6 is connected to an N-th gate line GLN and an M-th data line DLM. A gate electrode of the first switching element TFTH 6 is connected to the N-th gate line GLN. A source electrode of the first switching element TFTH 6 is connected to the M-th data line DLM. A drain electrode of the first switching element TFTH 6 is connected to a first end of the first liquid crystal capacitor CLCH 6 and a first end of the first storage capacitor CSTH 6 . A first pixel electrode is disposed at the first end of the first liquid crystal capacitor CLCH 6 . A common voltage VCOM is applied to a second end of the first liquid crystal capacitor CLCH 6 opposite to the first end of the first liquid crystal capacitor CLCH 6 through the common electrode. A storage voltage VCST is applied to a second end of the first storage capacitor CSTH 6 opposite to the first end of the first storage capacitor CSTH 6 . For example, according to an embodiment, the common voltage VCOM is the same or substantially equal to the storage voltage VCST.
[0242] The second switching element TFTL 6 is connected to the N-th gate line GLN and an (M+1)-th data line DLM+1 adjacent to the M-th data line DLM. A gate electrode of the second switching element TFTL 6 is connected to the N-th gate line GLN. A source electrode of the second switching element TFTL 6 is connected to the (M+1)-th data line DLM+1. A drain electrode of the second switching element TFTL 6 is connected to a first end of the second liquid crystal capacitor CLCL 6 and a first end of the second storage capacitor CSTL 6 . A second pixel electrode is disposed at the first end of the second liquid crystal capacitor CLCL 6 . A common voltage VCOM is applied to a second end of the second liquid crystal capacitor CLCL 6 opposite to the first end of the second liquid crystal capacitor CLCL 6 through the common electrode. A storage voltage VCST is applied to a second end of the second storage capacitor CSTL 6 opposite to the first end of the second storage capacitor CSTL 6 . In an exemplary embodiment, at least one of the first and second storage capacitors CSTH 6 and CSTL 6 is omitted.
[0243] The lookup tables of FIGS. 3 and 4 are applied to the display apparatus described in connection with FIG. 16 .
[0244] According to an exemplary embodiment, a data voltage charged to the first subpixel is different from a data voltage charged to the second subpixel in the 2D mode so that side visibility may be improved. The data voltage charged to the first subpixel is the same or substantially the same as the data voltage charged to the second subpixel in the 3D mode so that moiré may be prevented and the luminance of images may be improved.
[0245] An image on the first subpixel is transmitted to the first viewpoint and an image on the second subpixel is transmitted to the second viewpoint in the 3D mode so that the resolution of 3D images may be prevented from decreasing. As a consequence, display quality may be improved when the display panel displays 2D images and 3D images.
[0246] According to the embodiments of the present invention, side visibility may be improved when the display panel displays a 2D image, and a moiré phenomenon may be prevented and the luminance of images may be improved when the display panel displays a 3D image.
[0247] As a consequence, display quality may be improved when the display panel displays 2D images and 3D images.
[0248] The foregoing is illustrative of the embodiments of the present invention and is not to be construed as limiting thereof. Although a few example embodiments of the present invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments. Accordingly, all such modifications are intended to be included within the scope of the embodiments of the present invention as defined in the claims.
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A method of driving a display panel includes determining a driving mode including a two-dimensional (“2D”) mode and a three-dimensional (“3D”) mode and charging a voltage which varies according to the driving mode to at least one subpixel in a unit pixel of the display panel.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional application of Ser. No. 08/815,551, filed Mar. 12, 1997, now U.S. Pat. No. 6,207,602 which is a continuation application of Ser. No. 08/648,201, filed May 14, 1996, now abandoned, which is a continuation application of Ser. No. 08/344,419, filed Nov. 23, 1994, now abandoned.
This invention relates to nonwoven fabrics and to fabric laminates which comprise multiconstituent fibers formed from a select combination of polyolefin polymers. The invention more particularly relates to nonwoven fabrics and laminates of the type described having improved fabric properties and processing characteristics.
Nonwoven fabrics produced from spun polymer materials are used in a variety of different applications. Among other uses, such nonwoven fabrics are employed as the cover sheet for disposable diapers or sanitary products. There is considerable interest in making disposable diapers more comfortable and better fitting to the baby. An important part of the diaper comfort is the softness or hardness of the nonwovens used to make the diaper, including the diaper topsheet, barrier leg cuffs, and in some advanced designs, the fabric laminated to the backsheet film. In some diaper designs, a high degree of fabric elongation is needed to cooperate with elastic components for achieving a soft comfortable fit.
One approach to improved diaper topsheet softness is to use linear low density polyethylene (LLDPE) as the resin instead of polypropylene for producing spunbonded diaper nonwoven fabrics. For example, Fowells U.S. Pat. No. 4,644,045 describes spunbonded nonwoven fabrics having excellent softness properties produced from linear low density polyethylene. However, the above-described softness of LLDPE spunbonded fabric has never been widely utilized because of the difficulty in achieving acceptable abrasion resistance in such products. The bonding of LLDPE filaments into a spunbonded web with acceptable abrasion resistance has proven to be very difficult. Acceptable fiber tie down is observed at a temperature just below the point that the filaments begin to melt and stick to the calender. This very narrow bonding window has made the production of LLDPE spunbond fabrics with acceptable abrasion resistance very difficult. Thus, the softness advantage offered by LLDPE spunbonded fabrics has not been successfully captured in the marketplace.
The present invention is based upon the discovery that blending a relatively small proportion of polypropylene of a select class with the polyethylene imparts greatly increased abrasion resistance to a nonwoven fabric formed from the polymer blend, without significant adverse effect on the fabric softness properties. It is believed that the polyethylene and the polypropylene form distinct phases in the filaments. The lower-melting polyethylene is present as a dominant continuous phase and the higher-melting polypropylene is dispersed in the dominant polyethylene phase.
A number of prior publications describe fibers formed of blends of linear low density polyethylene and polypropylene. For example, U.S. Pat. No. 4,839,228 and EP 394,954 teach that useful fibers are formed from blends which are predominantly polypropylene. WO 90/10672 describes that useful fibers are prepared from blends of polypropylene and polyethylene, especially LLDPE, where the ratio of polypropylene to polyethylene is from 0.6 to 1.5. U.S. Pat. No. 4,874,666 describes fibers formed from a blend of LLDPE and high molecular weight crystalline polypropylene of melt flow rate below 20 g/10 minutes. U.S. Pat. No. 4,632,861 and 4,634,739 describe fibers formed from a blend of a branched low density polyethylene blended with from 5 to 35 percent polypropylene.
SUMMARY OF THE INVENTION
In accordance with the present invention, nonwoven fabrics and nonwoven fabric laminates are formed from fibers of a select blend of specific grades of polyethylene and polypropylene which give improved fabric performance not heretofore recognized or described, such as high abrasion resistance, good tensile properties, excellent softness and the like. Furthermore, these blends have excellent melt spinning and processing properties which permit efficiently producing nonwoven fabrics at high productivity levels.
The nonwoven fabrics of the present invention are comprised of fibrous material in the form of continuous filaments or staple fibers of a size less than 15 dtex/filament formed of a dispersed blend of at least two different polyolefin polymers. The polymers are present as a lower-melting dominant continuous phase and at least one higher-melting noncontinuous phase dispersed therein. The lower-melting continuous phase forms at least 70 percent by weight of the fiber. The physical and rheological behavior of these blends is part of a phenomenon observed by applicants wherein a small amount of a higher modulus polymer reinforces a softer, lower-modulus polymer and gives the blend better spinning, bonding and strength characteristics than the individual constituents. The lower melting, relatively low molulus polyethylene provides desirable properties such as softness, elongation and drape; while the higher-melting, higher modulus polypropylene phase imparts one or more of the following properties to the dominant phase: improved ability to bond the web; improved filament tie-down (reduces fuzz); improved web properties—tensiles, and/or elongation and/or toughness; rheological characteristics which improve spinning performance and/or web formation (filament distribution).
According to one advantageous and important aspect of the present invention, the lower-melting continuous phase comprises a linear low density polyethylene polymer of a melt index of greater than 10 (ASTM D1238-89, 190° C.) and a density of less than 0.945 g/cc (ASTMD-792). At least one higher-melting noncontinuous phase comprises a polypropylene polymer with melt flow rate of greater than 20 g/10 min (ASTM D1238-89, 230° C).
In one of the preferred embodiments of the invention, the lower-melting continuous phase forms at least 80 percent by weight of the fiber and comprises a linear low density polyethylene having a density of 0.90 -0.945 g/cc and a melt index of greater than 25 g/10 minutes.
In another preferred embodiment, said lower-melting polymer phase comprises linear low density polyethylene as described above and said higher-melting polymer phase comprises an isotactic polypropylene with a melt flow rate greater than 30 g/10 minutes.
In still another preferred embodiment said lower-melting polymer phase comprises at least 80 percent by weight low pressure, solution process, linear short chain branched polyethylene with a melt index of greater than 30 and a density of 0.945 g/cc and said higher-melting polymer phase comprises 1 to 20 percent by weight of isotactic polypropylene.
In another embodiment of the invention, said lower-melting polymer phase comprises linear low density polyethylene with a melt index of 27 and said higher-melting polymer phase comprises an isotactic polypropylene with a melt flow rate of 35 g/10 minutes.
According to another aspect of the present invention, the lower-melting dominant continuous phase is blended with a higher-melting noncontinuous phase of propylene co- and/or ter- polymers. When propylene co-and/or ter- polymers are used as the higher-melting noncontinuous phase, the lower melting continuous phase may be comprised of one or more polyethylenes selected from the group consisting of low density polyethylene, high pressure long chain branched polyethylene, linear low density polyethylene, high density polyethylene and copolymers thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings which form a portion of the original disclosure of the invention:
FIG. 1 diagrammatically illustrates one method and apparatus for manufacturing the nonwoven webs according to the invention;
FIG. 2 is a fragmentary plan view of a nonwoven web of the invention;
FIG. 3 is a diagrammatical cross-sectional view of a nonwoven fabric laminate in accordance with the invention; and
FIG. 4 is a diagrammatical cross-sectional view of a laminate of the nonwoven fabric of FIG. 2 with a film.
DETAILED DESCRIPTION
Linear low density polyethylene (LLDPE) is produced in either a solution or a fluid bed process. The polymerization is catalytic. Ziegler Natti and single-site metallocene catalyst systems have been used to produce LLDPE. The resulting polymers are characterized by an essentially linear backbone. Density is controlled by the level of comonomer incorporation into the otherwise linear polymer backbone. Various alpha-olefins are typically copolymerized with ethylene in producing LLDPE. The alpha-olefins which preferably have four to eight carbon atoms, are present in the polymer in an amount up to about 10 percent by weight. The most typical comonomers are butene, hexene, 4-methyl-1-pentene, and octene. The comonomer influences the density of the polymer. Density ranges for LLDPE are relatively broad, typically from 0.87-0.95 g/cc (ASTM D-792).
Linear low density polyethylene melt index is also controlled by the introduction of a chain terminator, such as hydrogen or a hydrogen donator. The melt index for a linear low density polyethylene can range broadly from about 0.1 to about 150 g/10 min. For purposes of the present invention, the LLDPE should have a melt index of greater than 10, and preferably 15 or greater for spunbonded filaments. Particularly preferred are LLDPE polymers having a density of 0.90 to 0.945 g/cc and a melt index of greater than 25.
Examples of suitable commercially available linear low density polyethylene polymers include the linear low density polyethylene polymers available from Dow Chemical Company, such as the ASPUN series of Fibergrade resins, Dow LLDPE 2500 (55 MI, 0.923 density), Dow LLDPE Type 6808A (36 MI, 0.940 density), and the Exact series of linear low density polyethylene polymers from Exxon Chemical Company, such as Exact 2003 (31 MI, density 0.921).
The higher-melting polypropylene component can be an isotactic or syndiotactic polypropylene homopolymer, or can be a copolymer or terpolymer of propylene. The melt flow rate of the polypropylene should be greater than 20 g/10 min., and preferably 25 or greater. Particularly suitable are polypropylene polymers having an MFR of 35 to 65. Examples of commercially available polypropylene polymers which can be used in the present invention include SOLTEX Type 3907 (35 MFR, CR grade), HIMONT Grade X10054-12-1 (65 MFR), Exxon Type 3445 (35 MFR), Exxon Type 3635 (35 MFR) AMOCO Type 10-7956F (35 MFR), and Aristech CP 350 J (melt flow rate approximately 35). Examples of commercially available copolymers of propylene include Exxon 9355 which is a random propylene copolymer with 3% ethylene, 35 melt flow rate; and co- and ter-polymers of propylene from the Catalloy™ series from Himont.
The lower-melting polyethylene component and the higher-melting polypropylene component can be present in proportions ranging from 70 percent by weight polyethylene and 30 percent polypropylene to 99 percent by weight polyethylene and 1 percent polypropylene. In these proportions, the lower-melting polyethylene component is present as a substantially continuous phase and the higher-melting polypropylene is present as a discontinuous phase dispersed in the polyethylene phase.
Appropriate combinations of polymers are combined and blended before being melt-spun into fibers or fibrous webs. A high degree of mixing is used in order to prepare blends in which the polypropylene component is highly dispersed in the polyethylene component. In some cases such mixing may be achieved in the extruder as the polymers are converted to the molten state. However, in other cases it may be preferred to use an extra mixing step. Among the commercially available mixers that can be used are the Barmag 3DD three-dimensional dynamic mixer supplied by Barmag AG of West Germany and the RAPRA CTM cavity-transfer mixer supplied by the Rubber and Plastics Research Association of Great Britain.
The blended polymer dispersion is then either melt-spun into fibers, which may be formed into a web for instance by carding, airlaying, or wetlaying, or melt-spun directly into fibrous webs by a spunbonding or meltblowing process. The web can then be bonded to form a strong, soft biconstituent-fiber nonwoven fabric. Webs of the blended polymer dispersion can be made according to any of the known commercial processes for making nonwoven fabrics, including processes that use mechanical, electrical, pneumatic, or hydrodynamic means for assembling fibers into a web, for example carding, wetlaying, carding/ hydroentangling, wetlaying/hydroentangling, and spunbonding. The webs of the blended polymer dispersion can then be bonded by a multiplicity of thermal bonds to give the webs sufficient strength and abrasion resistance to be useful in, for example, diaper applications. Preferably the bonds are thermal bonds formed by heating the fibers so that via a combination of heat and pressure they become tacky and fuse together at point of contact between the fibers. The thermal bonds may be formed using any of the techniques known in the art for forming discrete thermal bonds, such as calendering. Other thermal bonding techniques, such as through-air bonding and the like, may also be used.
FIG. 1 is a diagrammatical view of an apparatus, indicated generally by the reference number 10 , for producing a spunbonded nonwoven web in accordance with the present invention. Various spunbonding techniques exist, but all typically include the basic steps of extruding continuous filaments, quenching the filaments, drawing or attenuating the filaments by a high velocity fluid, and collecting the filaments on a surface to form a web. The spunbonding apparatus 10 is illustrated as a slotdraw type spunbonding apparatus, although, as will be appreciated by the skilled artisan, other spunbonding apparatus may be used. Spunbonding apparatus 10 includes a melt spinning section including a feed hopper 12 and an extruder 14 for the polymer. The extruder 14 is provided with a generally linear die head or spinneret 16 for melt spinning streams of substantially continuous filaments 18 . The substantially continuous filaments 18 are extruded from the spinneret 16 and typically are quenched by a supply of cooling air 20 . The filaments are directed to an attenuation device 22 , preferably in the form of an elongate slot which includes downwardly moving attenuation air which can be supplied from forced air above the slot, vacuum below the slot, or eductively within the slot, as is known in the art. In the attenuation device 22 , the filaments become entrained in a high velocity stream of attenuation air and are thereby attenuated or drawn. The air and filaments are discharged from the lower end of the attenuation device 22 and the filaments are collected on a forming wire 24 as a nonwoven spunbond web W.
The web W is conveyed to a bonding station 26 to form a coherent bonded nonwoven fabric. In the embodiment shown, the web is thermally bonded using a pair of heated calender rolls 27 and 28 . Thermal bonds are formed by heating the filaments so that they soften and become tacky, and fuse together contacting portions of the filaments. The operating temperature and the compression force of the heated rolls 27 and 28 should be adjusted to a surface temperature and pressure such that the filaments present in nonwoven web soften and bind the fibrous nonwoven web to thereby form a coherent nonwoven fabric. The pattern of the calender rolls may be any of those known in the art, including point bonding patterns, helical bonding patterns, and the like. The term point bonding is used herein to be inclusive of continuous or discontinuous pattern bonding, uniform or random point bonding, or a combination thereof, all as are well known in the art.
Although bonding station 26 has been illustrated in FIG. 1 as heated calender rolls, the rolls can, in other embodiments of the invention, be replaced by other thermal activation zones. For example, the bonding station may be in the form of a through-air bonding oven, a microwave or other RF treatment zone. Other bonding stations, such as ultrasonic welding stations, can also be used in the invention. In addition other bonding techniques known in the art can be used, such as adhesive bonding.
The thermally bonded nonwoven fabric is then wound by conventional means onto roll 29 . The nonwoven fabric can be stored on roll 29 or passed to end use manufacturing processes, for example for use as a component in a disposable personal care article such as diapers and the like, medical fabrics, wipes, and the like.
FIG. 2 illustrates a thermally bonded spunbonded nonwoven fabric W produced in accordance with the present invention. The nonwoven fabric W may be laminated into structures having a variety of desirable end-use characteristics. FIG. 3 is a diagrammatical cross-sectional view of a nonwoven fabric laminate in accordance with one embodiment of the invention. In this embodiment, the laminate, generally indicated at 40 , is a two-ply laminate. Ply 41 comprises a web which may be a meltblown nonwoven web, a spunbonded web, or a web of staple fibers. Ply 42 comprises a nonwoven web formed of a highly dispersed blend of polyolefin polymers, such as the nonwoven fabric W produced as described above.
The plies may be bonded and/or laminated in any of the ways known in the art. Lamination and/or bonding may be achieved, for example, by hydroentanglement of the fibers, spot bonding, through-air bonding and the like. For example, when ply 41 is a fibrous web, lamination and/or bonding may be achieved by hydroentangling, spot bonding, through-air bonding and the like. In the embodiment shown in FIG. 3, plies 41 and 42 are laminated together by passing through a heated patterned calender to form discrete thermal point bonds indicated at 43 . It is also possible to achieve bonding through the use of an appropriate bonding agent, i.e., an adhesive. The term spot bonding is inclusive of continuous or discontinuous pattern bonding, uniform or random point bonding or a combination thereof, all as are well known in the art.
The bonding may be made after assembly of the laminate so as to join all of the plies or it may be used to join only selected of the fabric plies prior to the final assembly of the laminate. Various plies can be bonded by different bonding agents in different bonding patterns. Overall, laminate bonding can also be used in conjunction with individual layer bonding.
Laminates of a spunbond web from the highly blended polymer dispersion as described above with a web of meltblown microfibers have utility as barrier fabrics in medical applications, protective clothing applications, and for hygiene applications such as barrier leg cuffs. Of particular utility for hygiene applications are spunbond/meltblown laminates of reduced basis weight, such as made with a 17 grams per square meter (gsm) spunbonded web of this invention and 2-3 gsm meltblown web. Such barrier laminates could be used, for example, as barrier leg cuffs in diapers.
Another type of nonwoven fabric laminate may be made by combining nonwoven web of this invention with a film, for example a film of a thermoplastic polymer, such as a polyolefin, to make barrier fabrics useful for hygiene applications such as barrier leg cuffs and diaper backsheets. FIG. 4 illustrates one such laminate, which includes a ply or layer 42 ′ comprising a nonwoven web formed of a highly dispersed blend of polyolefin polymers, such as the nonwoven fabric W of FIG. 2, laminated to a polyolefin film layer 44 , such as for example a polyethylene film of a thickness of 0.8 to 1 mil. Lamination and/or bonding of the nonwoven layer 42 ′ to the film layer 44 can be achieved by adhesive lamination using a continuous or discontinuous layer of adhesive. This adhesive approach may yield a diaper backsheet with superior softness and hand. The nonwoven fabric laminate could also be produced by thermal lamination of the nonwoven fabric of this invention and film webs together. This approach has the advantage of eliminating the cost of the adhesive. It may also be desirable to utilize coextruded film webs that include a sealing/bonding layer in combination with a polyolefin layer in the film web that, when combined with the nonwoven fabrics of the invention, maximize softness and good thermal bonding characteristics. The nonwoven fabric laminate could also be produced by direct extrusion of the film layer 44 on ply 42 ′.
EXAMPLE 1
Ninety percent by weight of a linear low density polyethylene (LLDPE) with a melt flow of 27 (Dow 6811 LLDPE) and ten percent by weight of a polypropylene (PP) polymer with a melt flow approximately 35 (Aristech CP 350 J) were dry blended in a rotary mixer. The dry-blended mixture was then introduced to the feed hopper of an extruder of a spunbond nonwoven spinning system. Continuous filaments were meltspun by a slot draw process at a filament speed of approximately 600 m/min and deposited upon a collection surface to form a spunbond nonwoven web, and the web was thermally bonded using a patterned roll with 12% bond area. For comparison purposes, nonwoven spunbond fabrics were produced under similar conditions with the same polymers, using 100% PP and 100% LLDPE.
As shown in table 1, the 100% LLDPE spunbond samples exhibited superior softness (75 and 77.5) compared to the 100% polypropylene spunbond sample (30). However, the abrasion resistance of the 100% LLDPE sample, as seen from the fuzz measurement, was relatively high (12.5 and 2.4) compared to the 100% PP sample (0.3). The nonwoven fabric formed from the 90% LLDPE/ 10% PP blend had a high softness (67.5) only slightly less than the 100% LLDPE fabric, and had abrasion resistance (fuzz value) of 1.0 mg., which is significantly better than the values seen for 100% LLDPE. The blend sample also showed improved CD tensile compared to products made with 100% LLDPE.
TABLE 1
Sample
A
B
C
D
C = comparison I = invention
C
C
C
I
Composition:
% polypropylene
100
0
0
10
% polyethylene
0
100
100
90
filament dia. (microns)
17.5
20.9
20.9
22.5
Basis weight (gsm) 1
23.1
25.2
24.6
24.8
Loft @ 95 g/in 2 (mils) 2
9.8
9.0
7.8
9.3
Fuzz (mg) 3
0.3
12.5
2.4
1.0
Softness 4
30
75
77.5
67.5
Strip Tensile (g/cm) 5
CD
557
139
157
164
MD
1626
757
639
467
Peak Elongation (%)
CD
90
116
129
108
MD
93
142
106
119
TEA (in.g./in
CD
852
297
346
354
MD
2772
2222
1555
1389
1 gsm = grams per square meter
2 Loft was determined by measuring the distance between the top and the bottom surface of the fabric sheet while the sheet was under compression loading of 95 grams per square inch. The measurement is generally the average of 10 measurements.
3 Fuzz is determined by repeatedly rubbing a soft elastomeric surface across the face of the fabric a constant number of times. The fiber abraded from the fabric surface is then weighed. Fuzz is reported as mg weight observed.
4 Softness was evaluated by an organoleptic method wherein an expert panel compared the surface feel of Example Fabrics with that of controls. Results are reported as a softness score with higher values denoting a more pleasing hand. Each reported value is for a single fabric test sample, but reflects the input of several panel members.
5 Tensile, Peak Elongation and TEA were evaluated by breaking a one inch by seven inch long sample generally following ASTM D1682-64, the one-inch cut strip test. The instrument cross-head speed was set at 5 inches per minute and the gauge length was set at 5 inches per minute. The Strip Tensile Strength, reported as grams per centimeter, is generally the average of at least 8 measurements. Peak Elongation is the percent
# increase in length noted at maximum tensile strength. TEA, Total Tensile Energy Absorption, is calculated from the area under the stress-strain curve generated during the Strip Tensile test.
EXAMPLE 2 (Control)
A control fiber was made by introducing 100% Dow LLDPE 2500 (55 MI, 0.923 density) to a feed hopper of a spinning system equipped with an extruder, a gear pump to control polymer flow at 0.75 gram per minute per hole, and a spinneret with 34 holes of L/D=4:1 and a diameter of 0.2 mm. Spinning was carried out using a melt temperature in the extruder of 215° C. and a pack melt temperature of 232° C. After air quench, the resulting filaments were drawn down at a filament speed of approximately 1985 m/min using an air aspiration gun operating at 100 psig to yield a denier of 3.01 and denier standard deviation of 0.41.
EXAMPLE 3
Ninety parts by weight of Dow LLDPE Type 2500 (55 MI, 0.923 density) and ten parts of Himont X 10054-12-1 polypropylene (65 MFR) were dry blended in a rotary mixer and then introduced to the feed hopper of the spinning system described in Example 2. Spinning was carried out using a pack melt temperature of 211° C. After air quench, the resulting filaments were drawn down at a filament speed of approximately 2280 M/Min using an air aspiration gun operating at 100 psig to yield a denier of 2.96 and a denier standard deviation of 1.37.
EXAMPLE 4
Ninety parts by weight of Dow LLDPE Type 2500 (55 MI, 0.923 density) and ten parts of Soltex 3907 polypropylene (35 MFR, 1.74 die swell, CR grade) were dry blended in a rotary mixer and then introduced to the feed hopper of the spinning system described in Example 2. Spinning was carried out using a pack melt temperature of 231° C. and an extruder melt temperature of 216° C. After air quench, the resulting filaments were drawn down at a filament speed of approximately 2557 M/Min using an air aspiration gun operating at 100 psig to yield a denier of 2.64 and a denier standard deviation of 0.38.
EXAMPLE 5
Ninety parts by weight of Dow LLDPE Type 6808A (36 MI, 0.940 density) and ten parts of Soltex 3907 polypropylene (35 MFR, 1.74 die swell, CR grade) were dry blended in a rotary mixer and then introduced to the feed hopper of the spinning system described in Example 2. Spinning was carried out using a pack melt temperature of 231° C. and an extruder melt temperature of 216° C. After air quench, the resulting filaments were drawn down at a filament speed of approximately 2129 M/Min using an air aspiration gun operating at 100 psig to yield a denier of 3.17 and a denier standard deviation of 2.22.
The quality of spinning for a given formulation has been found to roughly correlate with the denier standard deviation. A reduced standard deviation suggests more stable or higher quality spinning. Thus it is unexpected and contrary to the teaching of the prior art that the blend using a 35 MFR polypropylene in Example 4 yielded a more stable spinning than seen with the corresponding LLDPE control in Example 2.
EXAMPLE 6
Eighty parts by weight of a linear low density polyethylene pellets of 55 melt index and 0.925 g/cc density and twenty parts by weight polypropylene pellets of 35 melt flow rate were dry blended in a rotary mixer. The dry-blended mixture was then introduced to the feed hopper of a spinning system equipped with an extruder with a 30:1 l/d ratio, a static mixer, and a gear pump for feeding the molten polymer to a heated melt block fitted with a spinneret. Filaments were extruded from the spinneret and drawn using air aspiration.
EXAMPLE 7
Samples of continuous filament spunbonded nonwoven webs were produced from blends of a linear low density polyethylene with a melt flow rate of 27 (Dow 6811A LLDPE) and a polypropylene homopolymer (Appryl 3250YR1, 27 MFR) in various blend proportions. Control fabrics of 100 percent polypropylene and 100 percent polyethylene were also produced under similar conditions. The fabrics were produced by melt spinning continuous filaments of the various polymers or polymer blends, attenuating the filaments pneumatically by a slot draw process, depositing the filaments on a collection surface to form webs, and thermally bonding the webs using a patterned calender roll with a 12 percent bond area. The fabrics had a basis weight of approximately 25 gsm and the filaments had an average mass/length of 3 dtex. The tensile strength and elongation properties of these fabrics and their abrasion resistance were measured, and these properties are listed in Table 2. As shown, the 100 percent polypropylene control fabric had excellent abrasion resistance, as indicated by no measurable fuzz generation; however the fabrics had relatively low elongation. The 100 percent polyethylene control fabric exhibited good elongation properties, but very poor abrasion resistance (high fuzz values and low Taber abrasion resistance) and relatively low tensile strength. Surprisingly, the fabrics of the invention made of blends of polypropylene and polyethylene exhibited an excellent combination of abrasion resistance, high elongation, and good tensile strength. It is noted that the CD elongation values of the blends actually exceeded that of the 100% polyethylene control. This surprising increase in elongation is believed to be attributable to the better bonding of the filaments of the blend as compared to the bonding achieved in the 100% polyethylene control, which resulted in the fabrics of the invention making good use of the highly elongatable filaments without bond failure.
TABLE 2
MECHANICAL PROPERTIES OF
POLYPROPYLENE (PP)/POLYETHYLENE (PE) BLEND FABRICS
25/75
Fabric
100% PP
PP/PE
15/85 PP/PE
100% PE
MD Tensile (g/cm) 6
925
764
676
296
CD Tensile (g/cm) 6
405
273
277
63
MD Elongation (%) 6
62
170
199
168
CD Elongation (%) 6
70
190
224
131
Fuzz (mg) 7
0.0
0.3
0.5
19.0
Taber Abrasion 8
40
32
22
10
(cycles-rubber wheel)
Taber Abrasion 8
733
200
500
15
(cycles - felt wheel)
6 Tensile and Peak Elongation were evaluated by breaking a one inch by seven inch long sample generally following ASTM D1682-64, the one-inch cut strip test. The instrument cross-head speed was set at 5 inches per minute and the gauge length was set at 5 inches per minute. The Strip Tensile Strength, reported as grams per inch, is generally the average of at least 8 measurements. Peak Elongation is the percent increase in length noted at maximum tensile strength.
7 Fuzz is determined by repeatedly rubbing a soft elastomeric surface across the face of the fabric a constant number of times. The fiber abraded from the surface is then weighed. Fuzz is reported as mg weight observed.
8 Conducted according to ASTM D3884-80 where the number of cycles was counted until failure. Failure was defined as the appearance of a hole of one square millimeter or greater in the surface of the fabric.
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Nonwoven fabrics and fabric laminates are formed from continuous filaments or staple fibers of a select blend of specific grades of polyethylene and polypropylene which give improved fabric performance not heretofore recognized or described, such as high abrasion resistance, good tensile properties, excellent softness and the like. Furthermore, these blends have excellent melt spinning and processing properties which permit efficiently producing nonwoven fabrics at high productivity levels. The polymers are present as a lower-melting dominant continuous phase and at least one higher-melting noncontinuous phase dispersed therein. The lower-melting continuous phase forms at least 70 percent by weight of the fiber and comprises a linear low density polyethylene polymer of a melt index of greater than 10 and a density of less than 0.945 g/cc. At least one higher-melting noncontinuous phase comprises a polypropylene polymer with melt flow rate of greater than 20 g/10 min.
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BACKGROUND OF THE INVENTION
The advantages of controlled release products are well known in the pharmaceutical field and include the ability to maintain a desired blood level of a medicament over a comparatively longer period of time while increasing patient compliance by reducing the number of administrations necessary to achieve the same. These advantages have been attained by a wide variety of methods. For example, different hydrogels have been described for use in controlled release medicines, some of which are synthetic, but most of which are semi-synthetic or of natural origin. A few contain both synthetic and non-synthetic material. However, some of the systems require special process and production equipment, and in addition some of these systems are susceptible to variable drug release.
Oral controlled release delivery systems should ideally be adaptable so that release rates and profiles can be matched to physiological and chronotherapeutic requirements.
Other pharmaceutical dosage forms are known in the art which provide release of a medicament at a local site for absorption into the body. For example, U.S. Pat. No. 4,829,056 (Sugden) describes a buccal tablet consisting of etorphine, at least one monosaccharide, disaccharide or a mixture thereof, and a mixture of xanthan gum and locust bean gum in a weight ratio of 3:1 to 1:1, wherein the total weight of the mono- and/or di-saccharides relative to the combined weight of the xanthan and locust bean gums is in the ratio of 20:1 to 3:1. The buccal tablet of this reference is intended to be placed between the gingival surface of the jaw and the buccal mucosa where it gels to produce a soft hydrated tablet which may be retained in position so as to provide release of etorphine for up to two hours. The buccal tablet is said to provide improved bioavailability.
U.S. Pat. No. 4,948,580 (Browning) describes a bioadhesive composition which may be employed as an oral drug delivery system and includes a freeze-dried polymer mixture formed of the copolymer poly(methyl vinyl ether/maleic anhydride) and gelatin dispersed in an ointment base. This composition is said to be useful to deliver oral mucosa active ingredients such as steroids, antifungal agents, antibacterial agents, etc.
In other instances, the active ingredient is not intended to be absorbed into the body. In such cases, local non-systemic activity is provided by the active ingredient.
For example, U.S. Pat. No. 4,597,959 (Barr) describes a cosmetic breath freshener composition in wafer form which is said to have slow release properties. The composition includes a multiplicity of microencapsulated liquid droplets of flavoring material contained in a base which has an adhesive therein.
U.S. Pat. No. 5,077,051 (Gallopo et al.) describes bioadhesive microcapsules which comprise xanthan gum, locust bean gum, a bulking agent and an active agent. These microcapsules are said to be particularly useful for delivering buffering agents to the oral cavity for anticarious purposes. The microcapsules are prepared by preparing a hot aqueous solution or suspension of the active agent; adding xanthan gum, locust bean gum and a bulking agent to form a viscous solution; and then (a) cooling and then drying the viscous solution to obtain a solid material which is then formed into microcapsules, or (b) spray-drying the viscous solution to form the microcapsules.
U.S. Pat. No. 4,915,948 (Gallopo et al.) describes a tablet which is said to have improved bio-adhesion to mucus membranes. The tablet includes a water soluble biopolymer selected from xanthan gum, a pectin and mixtures thereof, and a solid polyol having a solubility at room temperature in water greater than about 20 g/100 g solution.
U.S. Pat. Nos. 4,994,276, 5,128,143, and 5,135,757, hereby incorporated by reference, reported that a controlled release excipient which is comprised of synergistic heterodisperse polysaccharides (e.g., a heteropolysaccharide such as xanthan gum in combination with a polysaccharide gum capable of cross-linking with the heteropolysaccharide, such as locust bean gum) is capable of processing into oral solid dosage forms using either direct compression, following addition of drug and lubricant powder, conventional wet granulation, or a combination of the two. The release of the medicament from the formulations therein proceeded according to zero-order or first-order mechanisms.
The controlled release excipients disclosed in U.S. Pat. Nos. 4,994,276, 5,128,143, and 5,135,757 are commercially available under the tradename TIMERx™ from Edward Mendell Co., Inc., Patterson, N.Y., which is the assignee of the present invention.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide an excipient and tablet formulation capable of releasing a active ingredient which is substantially not absorbed into the body, but which instead provides a localized effect.
It is a further object of the present invention to provide a bioadhesive tablet formulation which is relatively easy and inexpensive to prepare, and which provides a localized effect of an active ingredient(s) contained therein for an extended amount of time.
It is a further object of the present invention to provide a controlled release excipient which is bioadhesive and which is directly compressible.
The above-mentioned objects and others are achieved by virtue of the present invention, which relates in part to a bioadhesive controlled release excipient which is directly compressible and which comprises a heterodisperse material comprising a heteropolysaccharide gum and a homopolysaccharide gum, and an inert pharmaceutically acceptable diluent. The ratio of diluent to heterodisperse material in the excipient formulation is not critical; however, the ratio of diluent to heterodisperse material in the final controlled release product is preferably from about 21:1 to about 200:1, and more preferably from about 21:1 to about 100:1.
In one preferred embodiment of the present invention, the controlled release excipient further comprises an additional bioadhesive agent(s), for example, carbomer, poly carbophil, poly oxyethylene oxide, and/or other bioadhesive agents known to those skilled in the art.
The present invention further relates to a controlled release solid dosage form, comprising a heterodisperse material comprising a heteropolysaccharide gum and a homopolysaccharide gum capable of cross-linking said heteropolysaccharide gum in the presence of aqueous solutions, the ratio of said heteropolysaccharide gum to said homopolysaccharide gum being from about 1:3 to about 3:1; an inert pharmaceutical diluent selected from the group consisting of monosaccharide, a disaccharide, a polyhydric alcohol, and mixtures thereof, the ratio of said inert diluent to said heterodisperse material being from about 21:1 to about 200:1; and an effective amount of a locally active agent to provide a localized effect in the environment of use, the heterodisperse material causing said solid dosage form to be bioadhesive when exposed to fluids present in the environment of use, e.g., a body cavity. In a preferred embodiment, the formulation of the present invention comprises a tablet. In a further preferred embodiment, the heteropolysaccharide gum is a xanthan gum and the homodisperse gum is locust bean gum.
In one preferred embodiment of the present invention, the controlled release solid dosage form further comprises a desired amount of an additional bioadhesive agent as previously mentioned.
The present invention further relates to a method for preparing an solid dosage form which is directly compressible and which is bioadhesive when placed in contact with a mucous membrane. In the method, a heteropolysaccharide gum is mixed with a homopolysaccharide gum capable of cross-linking said heteropolysaccharide gum in the presence of aqueous solutions, such that the ratio of said heteropolysaccharide gum to said homopolysaccharide gum is from about 1:3 to about 3:1, to obtain a heterodisperse gum matrix. An inert pharmaceutical diluent is added to said heterodisperse gum matrix for providing sufficient bulk for handling, formulation purposes, etc. The inert pharmaceutical diluent may also contain one or more agents which are recognized as having bioadhesive properties, such as sorbitol. The bioadhesive excipient is thereafter combined with a locally active agent and a further amount of inert diluent (optional), such that the ratio of the inert diluent to said heterodisperse gum matrix in the final product is from about 21:1 to about 200:1.
The present invention further relates to a directly compressible slow release excipient which includes a heterodisperse gum matrix comprising a heteropolysaccharide gum and a homopolysaccharide gum capable of cross-linking the heteropolysaccharide gum in the presence of aqueous solutions, a bioadhesive agent selected from the group consisting of carbomer, poly carbophil, poly oxyethylene oxide, and mixtures of any of the foregoing, and an inert pharmaceutical diluent selected from the group consisting of monosaccharide, a disaccharide, a polyhydric alcohol, and mixtures thereof. The ratio of the heteropolysaccharide gum to the homopolysaccharide gum is preferably from about 1:3 to about 3:1. In a preferred embodiment, the controlled release bioadhesive excipient of comprises from about 10 to about 50 percent by weight heterodisperse gum matrix, from about 10 to about 50 percent by weight bioadhesive agent, and from about 40 to about 80 percent inert diluent. More preferably, the controlled release excipient comprises from about 10 to about 30 percent by weight heterodisperse gum matrix, from about 10 to about 30 percent by weight bioadhesive agent, and from about 40 to about 80 percent inert diluent.
DETAILED DESCRIPTION
The term "heteropolysaccharide" as used in the present invention is definedas a water-soluble polysaccharide containing two or more kinds of sugar units, the heteropolysaccharide having a branched or helical configuration, and having excellent water-wicking properties and immense thickening properties. When admixed with an appropriate homopolysaccharidegum capable of cross-linking with the heteropolysaccharide in accordance with the present invention and exposed to an aqueous solution, gastric fluid, etc., the gums pack closely and many intermolecular attachments areformed which make the structure strong and provide a hydrophilic gum matrixhaving high gel strength.
Xanthan gum, the preferred heteropolysaccharide, is produced by microorganisms, for instance, by fermentation with the organism xanthomonas compestris. Most preferred is xanthan gum which is a high molecular weight (>10 6 ) heteropolysaccharide. Xanthan gum contains D-glucose, D-mannose, D-glucuronate in the molar ratio of 2.8:2.0:20, and is partially acetylated with about 4.7% acetyl. Xanthan gum also includes about 3% pyruvate, which is attached to a single unit D-glucopyromosyl side chain as a metal. It dissolves in hot or cold water and the viscosityof aqueous solutions of xanthan gum is only slightly affected by changes inthe pH of a solution between 1 and 11. Xanthan gum is known to possess goodbioadhesive properties.
Other preferred heteropolysaccharides include derivatives of xanthan gum, such as deacylated xanthan gum, the carboxymethyl ether, and the propyleneglycol ester.
The homopolysaccharide gums used in the present invention which are capableof cross-linking with the heteropolysaccharide include the galactomannans, i.e., polysaccharides which are composed solely of mannose and galactose.
A possible mechanism for the interaction between the galactomannan and the heteropolysaccharide involves the interaction between the helical regions of the heteropolysaccharide and the unsubstituted mannose regions of the galactomannan. Galactomannans which have higher proportions of unsubstituted mannose regions have been found to achieve more interaction with the heteropolysaccharide. Hence, locust bean gum, which has a higher ratio of mannose to the galactose, is especially preferred as compared to other galactomannans such as guar and hydroxypropyl guar.
The inert diluent of the excipient preferably comprises a pharmaceutically acceptable saccharide, including a monosaccharide, a disaccharide, and/or mixtures thereof. Examples of suitable inert pharmaceutical diluents include sucrose, dextrose, lactose, microcrystalline cellulose, fructose, xylitol, sorbitol, mannitol, mixtures thereof and the like.
Preferably, the excipient of the present invention has uniform packing characteristics over a range of different particle size distributions and is capable of processing into tablets using either direct compression, following addition of drug and lubricant powder or conventional wet granulation.
The properties and characteristics of a specific excipient system prepared according to the present invention is dependent in part on the individual characteristics of the homo and hetero polysaccharide constituents, in terms of polymer solubility, glass transition temperatures etc., as well as on the synergism both between different homo and heteropolysaccharides and between the homo and heteropolysaccharides and the inert saccharide constituent(s) in modifying dissolution fluid-excipient interactions.
A homodisperse system of a heteropolysaccharide typically produces a highlyordered, helical or double helical molecular conformation which provides high viscosity without gel formation. In contrast, a homodisperse system of a homopolysaccharide typically is only slowly soluble and ungelled at low temperatures. Two steps which are generally required for gelation are the fast hydration of the macromolecules which comprise the hydrodisperse polysaccharide material and thereafter the association of the molecules toform gels. These two important properties which are necessary to achieve a slow release hydrophilic matrix are maximized in the present invention by the particular combination of materials. Prolonged exposure to the dissolution fluid promotes solubilization, which allows molecules to associate and undergo gelation, and may result in intermacromolecular cross-linking in ribbon or helical "smooth" regions.
The heterodisperse excipient of the present invention comprises both hetero- and homo- polysaccharides which exhibit synergism. The heteropolysaccharide component acts to produce a faster gelation of the homopolysaccharide component and the homopolysaccharide acts to cross-linkthe normally free heteropolysaccharide helices. The resultant gel is faster-forming and more rigid. Heteropolysaccharides such as xanthan gum have excellent water wicking properties which provide fast hydration. On the other hand, the combination of xanthan gum with homopolysaccharide gums which are capable of cross-linking the rigid helical ordered structure of the xanthan gum (i.e. with unsubstituted mannose regions in the galactomannans) thereby act synergistically to provide a higher than expected viscosity (i.e., high gel strength) of the matrix. The combination of xanthan gum with locust bean gum with or without the other homopolysaccharide gums is especially preferred. However, the combination of any homopolysaccharide gums known to produce a synergistic effect when exposed to aqueous solutions may be used in accordance with the present invention. By synergistic effect, it is meant that the combination of two or more polysaccharide gums produce a higher viscosity and/or faster hydration than that which would be expected by either of the gums alone.
It is also possible that the type of synergism which is present with regardto the gum combination of the present invention could also occur between two homogeneous or two heteropolysaccharides.
In the present invention, it has been discovered that the controlled release properties of the tablets of the present invention are optimized when the ratio of heteropolysaccharide gum to homopolysaccharide material is about 1:1, although heteropolysaccharide gum in an amount of from about20 to about 80 percent or more by weight of the heterodisperse polysaccharide material provides an acceptable slow release product.
The rate-limiting step for the release of the active agent in the present invention is believed to be dependent to a large extent upon the penetration of water into the tablet to dissolve the polysaccharides and the drug(s).
The combination of the heterodisperse polysaccharide material (e.g., a mixture of xanthan gum and locust beam gum) with the inert diluent provides a ready-to-use excipient product in which a formulator need only blend the desired active medicament, an optional lubricant, and any remaining diluent needed to provide a final ratio of inert diluent to heterodisperse polysaccharide material from about 21:1 to about 200:1.
In one preferred embodiment of the present invention, the final controlled release product contains from about 0.1% to about 20%, and more preferablyfrom about 1% to about 10% of an additional bioadhesive agent. The additional bioadhesive agent may be, for example, carbomer, poly carbophil, poly oxyethylene oxide, and others known to those skilled in the art. Especially preferred are water soluble poly(ethylene oxide) polymers. Such poly(ethylene oxide) polymers are commercially available from Union Carbide Chemicals and Plastics Company, Inc., Bound Brook, N.J., U.S.A. under the tradename Polyox®.
The pharmaceutical excipients prepared in accordance with the present invention may be prepared according to any agglomeration technique to yield an acceptable excipient product.
In wet granulation techniques, the desired amounts of the heteropolysaccharide gum, the homopolysaccharide gum, and the inert saccharide diluent are mixed together and thereafter a moistening agent such as water, propylene glycol, glycerol, alcohol or the like is added toprepare a moistened mass. Next, the moistened mass is dried. The dried massis then milled with conventional equipment into granules. Therefore, the excipient product is ready to use.
The excipient is free-flowing and directly compressible. Accordingly, the excipient may be mixed in the desired proportion with a locally active agent and optional lubricant (dry granulation). Alternatively, all or partof the excipient may be subjected to a wet granulation with the active ingredient and thereafter tableted. The complete mixture, in an amount sufficient to make a uniform batch of tablets, is then subjected to tableting in a conventional production scale tableting machine at normal compression pressure, i.e. about 2000-1600 lbs/sq in. However, the mixtureshould not be compressed to such a degree that there is subsequent difficulty in its hydration when exposed to gastric fluid.
One of the limitations of direct compression as a method of tablet manufacture is the size of the tablet. If the amount of active is high a pharmaceutical formulator may choose to wet granulate the active with other excipients to attain an acceptably sized tablet with the desired compact strength. Usually the amount of filler/binder or excipients neededin wet granulation is less than that in direct compression since the process of wet granulation contributes to some extent toward the desired physical properties of a tablet.
The average tablet size for round tablets is preferably about 50 mg to 500 mg and for capsule-shaped tablets about 200 mg to 2000 mg. However, it is contemplated that for certain uses, e.g., antacid tablets, vaginal tabletsand possibly implants, that the tablet will be larger.
The average particle size of the granulated excipient of the present invention ranges from about 50 microns to about 400 microns and preferablyfrom about 185 microns to about 265 microns. The particle size of the granulation is not narrowly critical, the important parameter being that the average particle size of the granules, must permit the formation of a directly compressible excipient which forms pharmaceutically acceptable tablets. The desired tap and bulk densities of the granulation of the present invention are normally between from about 0.3 to about 0.8 g/ml, with an average density of from about 0.5 to about 0.7 g/ml. For best results, the tablets formed from the granulations of the present inventionare from about 6 to about 8 kg hardness. The average flow of the granulations prepared in accordance with the present invention are from about 25 to about 40 g/sec. Tablets compacted using an instrumented rotarytablet machine have been found to possess strength profiles which are largely independent of the inert saccharide component.
The bioadhesive controlled release formulations of the present invention may be utilized in an environment where they contact mucosa and are exposed to bodily fluids, e.g. the oral cavity. For example, the formulation of the present invention may be suitably shaped to be placed at any convenient place on the palate or on the upper or lower gums and adjacent to the cheek of the user so that saliva in the mouth causes the formulation to adhere to the gum, while the locally active agent is slowlyreleased from the formulation over a desired period of time. Other formulations prepared in accordance with the present invention may be suitably shaped for use in other body cavities, e.g., periodontal pockets,surgical wounds, vaginally. The formulation may be prepared using an appropriate amount of the heterodisperse excipient to provide a release ofthe locally active agent for at least 0.5 hours, and over a period of from about 0.5 to about 3 hours when the active agent is intended for use in the oral cavity, depending upon the active agent and the desired treatmentperiod.
A wide variety of locally active agents can be used in conjunction with thepresent invention, and include both water soluble and water insoluble agents. The locally active agent(s) which may be included in the controlled release formulation of the present invention is intended to exert its effect in the environment of use, e.g., the oral cavity, although in some instances the active agent may also have systemic activity via absorption into the blood via the surrounding mucosa.
The locally active agent(s) include antifungal agents (e.g-, amphotericin B, clotrimazole, nystatin, ketoconazole, miconazol, etc.), antibiotic agents (penicillins, cephalosporins, erythromycin, tetracycline, aminoglycosides, etc.), antiviral agents (e.g, acyclovir, idoxuridine, etc.), breath fresheners (e.g. chlorophyll), antitussive agents (e.g., dextromethorphan hydrochloride), anti-cariogenic compounds (e.g. metallic salts of fluoride, sodium monofluorophosphate, stannous fluoride, amine fluorides), analgesic agents (e.g., methylsalicylate, salicylic acid, etc.), local anesthetics (e.g., benzocaine), oral antiseptics (e.g., chlorhexidine and salts thereof, hexylresorcinol, dequalinium chloride, cetylpyridinium chloride), anti-flammatory agents (e.g., dexamethasone, betamethasone, prednisone, prednisolone, triamcinolone, hydrocortisone, etc.), hormonal agents (oestriol), antiplaque agents (e.g, chlorhexidine and salts thereof, octenidine, and mixtures of thymol, menthol, methysalicylate, eucalyptol), acidity reducing agents (e.g., buffering agents such as potassium phosphate dibasic, calcium carbonate, sodium bicarbonate, sodium and potassium hydroxide, etc.), and tooth desensitizers (e.g., potassium nitrate). This list is not meant to be exclusive.
The amount of the active agent included in the final controlled release product may be determined by one skilled in the art without undue experimentation, and is generally from about 0.1% to about 20% by weight of the final product, and more preferably from about 1% to about 10% by weight of the final product. The particular amount of active agent included will, of course, depend upon the particular agent and its intended use.
The controlled release solid dosage form of the present invention may also include other locally active agents, such as flavorants and sweeteners.
The flavoring agents which may be used in the present invention may be solid or liquid and may be chosen from natural or synthetic flavors. When the flavoring agent is a liquid, it may be sprayed onto the controlled release excipient or onto additional diluent to be added to the controlledrelease excipient.
When the flavoring agent is an oil, it may be sprayed onto dry granules as an alcoholic solution or incorporated in the talcum lubricant. The flavoring agent is preferably not incorporated during wet processing, since the subsequent drying would reduce the concentration of these volatile ingredients.
The flavoring agent may be a common flavorant including wintergreen, peppermint, spearmint, menthol, fruit flavors, vanilla, cinnamon, various spices, or others known in the art.
Generally any flavoring or food additive such as those described in Chemicals Used in Food Processing, pub 1274 by the National Academy of Sciences, pages 63-258 may be used.
The amount of flavoring employed is normally a matter of preference subjectto such factors as flavor type, individual flavor, and strength desired. Generally, the final product may include from about 0.1% to about 5% by weight flavorant.
Some of the sweeteners useful in the present invention include sucrose and aspartame (1-methyl N-L-α-aspartyl-L-phenyl-alanine). In general, sweeteners may be included in an amount from about 0,001% to about 5.0% byweight of the final product.
The tablets of the present invention may also contain effective amounts of coloring agents, (e.g., titanium dioxide, F.D. & C. and D. & C. dyes; see the Kirk-Othmer Encyclopedia of Chemical Technology, Vol. 5, pp. 857-884, hereby incorporated by reference), stabilizers, binders, odor controlling agents, and preservatives.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following examples illustrate various aspects of the present invention.They are not to be construed to limit the claims in any manner whatsoever.
EXAMPLE A
The controlled release excipient is prepared by combining xanthan gum, locust bean gum, and dextrose in the amounts set forth in Table 1 below, and dry blending (Baker Perkin [Machine#5407], blender settings (chopper=1000rpm, impeller=800 rpm)) the mixture for 2 minutes. Thereafter, water (115 ml) is added slowly and the mixture is blended for 1.5 minutes. The mixture is then dried overnight at 50° C. in an oven. Next, the mixture is screened through a 20 mesh screen, with particles larger than 20 mesh being discarded.
TABLE 1______________________________________Excipient GranulationIngredient % g/1000 g______________________________________Xanthan gum 25.0 225.0Locust bean gum 25.0 225.0Dextrose 50.0 450.0Total 100.0% 900 g______________________________________
EXAMPLES 1-3
Oral hygiene/Antitussive Tablets
In Examples 1-3, a locally active agent (in this case, a local anesthetic, oral antiseptic, an anti-cariogenic, an anti-plaque agent) is added to thegranulated controlled release excipient prepared in Example A and the mixture is blended in a conventional 2 quart Hobart V-blender for 10 minutes, as set forth in Table 2 below.
TABLE 2______________________________________Examples 1-3 Percent IncludedIngredient Range % Ex. 1 Ex. 2 Ex. 3______________________________________Controlled Release 90-99% 99 95 90ExcipientActive agent 1-10% 1 5 10Total 100 100 100 100______________________________________
Thereafter, the blended mixture is mixed with the desired amount of diluent(in this case, a mixture of mannitol, dextrose and sucrose) for 10 minutes in the V-blender. Next, about 1% by weight lubricant (hydrogenated vegetable oil) is added with further mixing for 5 minutes. The final composition of Examples 1-3 are set forth in Table 3 below.
TABLE 3______________________________________Examples 1-3 Percent IncludedIngredient Range % Ex. 1 Ex. 2 Ex. 3______________________________________Granulation - CR* 1-9% 1% 5% 9%Excipient + Active AgentDiluent (mannitol, 90-98% 98% 94% 90%dextrose, sucrose)Lubricant 1% 1% 1% 1%(Hyd. Veg. Oil)Total 100% 100% 100% 100%Ratio of diluent:gum** 200:1 40:1 21:1______________________________________*CR = controlled release**Approximate
Finally, the mixture of Examples 1-3 are tableted to provide tablets from 50 mg to 1000 mg. The tablets of Examples 1-3 may be used as, e.g., an oral hygiene product or as cough drops.
EXAMPLE 4
Antacid Tablets
In Example 4, a locally active agent (in this case, an antacid) is added to40-90 parts of the granulated controlled release excipient prepared in Example A and the mixture is granulated by conventional wet-granulation techniques using either water or an acceptable granulating agent in a conventional mixer. Thereafter, the granules are dried at 60° C. ina fluid bed dryer, or in any other fashion known to those skilled in the art.
To 50-80 parts of the dried granules, a diluent of 19-49 parts is added, and the mixture is blended for 10 minutes. Next, 1% lubricant is added andthe mixture is blended for an additional 5 minutes. Finally, the blended mixture is compressed on a tablet press to provide tablets having a weightfrom 250 mg to 2000 mg. The final product of Example 2 is a sustained action antacid tablet.
EXAMPLES 5-8
Inclusion of Bioadhesive Polymer
In Examples 5-8, a locally active agent (in this case, a local anesthetic, oral antiseptic, an anti-cariogenic, an anti-plaque agent) is added to thegranulated controlled release excipient prepared in Example A and the mixture is blended in a conventional 2 quart Hobart V-blender for 10 minutes.
Thereafter, 1-10 parts of the blended mixture is mixed with the diluent (inthis case, a mixture of mannitol, dextrose and sucrose) an 10 parts bio-adhesive agent (in this case either carbomer, poly carbophil, or poly oxyethylene oxide) for 10 minutes in the V-blender. Next, about 1% by weight lubricant (hydrogenated vegetable oil) is added with further mixingfor 5 minutes. (See Table 3).
TABLE 3______________________________________Examples 5-8 Percent IncludedIngredient Range % Ex. 5 Ex. 6 Ex. 7 Ex. 8______________________________________Granulation - CR* 1-8% 1% 5% 5% 8%Excipient +Active AgentBioadhesive 10% 10% 5% 10% 10%AgentDiluent (mannitol, 81-88% 88% 89% 84% 81%dextrose, sucrose)Lubricant 1% 1% 1% 1% 1%(Hyd. Veg. Oil)Total 100% 100% 100% 100% 100%Ratio diluent:gum** 178:1 37:1 35:1 21:1______________________________________*CR = controlled release**Approximate
Finally, the mixture is tableted to provide tablets from 50 mg to 1000 mg. The tablets of Examples 5-8 may be used as, e.g., an oral hygiene product or as cough drops.
The examples provided above are not meant to be exclusive. Many other variations of the present invention would be obvious to those skilled in the art, and are contemplated to be within the scope of the appended claims.
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The present invention relates to a controlled release bioadhesive tablet which includes a locally active agent, a heterodisperse gum matrix, and a pharmaceutically acceptable diluent. In certain preferred embodiments, the tablet further includes an additional bioadhesive agent. The final product adheres to mucous membranes and releases the locally active agent over a desired period of time. Also disclosed is a bioadhesive excipient useful in the preparation of these tablets.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in part of each of the following: U.S. patent application Ser. No. 12/635,025 (“'025”), filed Dec. 10, 2009; U.S. patent application Ser. No. 12/635,064 (“'064”), filed Dec. 10, 2009; U.S. patent application Ser. No. 12/635,124 (“'124”), filed Dec. 10, 2009; U.S. patent application Ser. No. 12/635,143 (“'143”), filed Dec. 10, 2009; and U.S. patent application Ser. No. 12/635,201 (“'201”), filed Dec. 10, 2009. And these parent applications are in turn related to other applications as follows. '025 is a continuation-in-part of U.S. patent application Ser. No. 12/469,312, filed May 20, 2009, which is a continuation-in-part of U.S. patent application Ser. No. 12/469,258, also filed May 20, 2009, which is a continuation-in-part of U.S. patent application Ser. No. 11/829,461, filed Jul. 27, 2007, now U.S. Pat. No. 7,537,530, which is a continuation-in-part of U.S. patent application Ser. No. 11/772,903, filed Jul. 3, 2007, now U.S. Pat. No. 7,537,529; further a continuation-in-part of U.S. patent application Ser. No. 12/492,514, filed Jun. 26, 2009; still further a continuation-in-part of U.S. patent application Ser. Nos. 12/558,732 and 12/558,726, filed Sep. 14, 2009, which are continuations of U.S. patent application Ser. No. 12/186,877, filed Aug. 6, 2008, which is a continuation of U.S. Pat. No. 7,410,429, filed Aug. 1, 2007, which is a continuation-in-part of U.S. Pat. No. 7,537,530, filed Jul. 27, 2007, which is a continuation-in-part of U.S. Pat. No. 7,537,529, filed Jul. 3, 2007. '064 is a continuation-in-part of '025, which is related to other applications as set forth above. '124 is a continuation-in-part of '064, which is related to other applications as set forth above. '143 is a continuation-in-part of '025, which is related to other applications as set forth above. '201 is a continuation-in-part of '143, which is related to other applications as set forth above. The entire disclosure of each of these references is hereby incorporated herein by reference.
FIELD OF THE INVENTION
The present invention generally relates to golf balls and more particularly is directed to golf balls having multi-layered cores comprising a hardness gradient within each core layer as well as from core layer to core layer.
BACKGROUND OF THE INVENTION
Golf balls have conventionally been constructed as either two piece balls or three piece balls. The choice of construction between two and three piece affects the playing characteristics of the golf balls. The differences in playing characteristics resulting from these different types of constructions can be quite significant.
Three piece golf balls, which are also known as wound balls, are typically constructed from a liquid or solid center surrounded by tensioned elastomeric material. Wound balls are generally thought of as performance golf balls and have a good resiliency, spin characteristics and feel when struck by a golf club. However, wound balls are generally difficult to manufacture when compared to solid golf balls.
Two piece balls, which are also known as solid core golf balls, include a single, solid core and a cover surrounding the core. The single solid core is typically constructed of a crosslinked rubber, which is encased by a cover material. For example, the solid core can be made of polybutadiene which is chemically crosslinked with zinc diacrylate or other comparable crosslinking agents. The cover protects the solid core and is typically a tough, cut-proof material such as SURLYN®, which is a trademark for an ionomer resin produced by DuPont. This combination of solid core and cover materials provides a golf ball that is virtually indestructible by golfers. Typical materials used in these two piece golf balls have a flexural modulus of greater than about 40,000 psi. In addition, this combination of solid core and cover produces a golf ball having a high initial velocity, which results in improved distance. Therefore, two piece golf balls are popular with recreational golfers because these balls provide high durability and maximum distance.
The stiffness and rigidity that provide the durability and improved distance, however, also produce a relatively low spin rate in these two piece golf balls. Low spin rates make golf balls difficult to control, especially on shorter shots such as approach shots to greens. Higher spin rates, although allowing a more skilled player to maximize control of the golf ball on the short approach shots, adversely affect driving distance for less skilled players. For example, slicing and hooking the ball are constant obstacles for the lower skill level players. Slicing and hooking result when an unintentional side spin is imparted on the ball as a result of not striking the ball squarely with the face of the golf club. In addition to limiting the distance that the golf ball will travel, unintentional side spin reduces a player's control over the ball. Lowering the spin rate of the golf ball reduces the adverse effects of unintentional side spin. Hence, recreational players typically prefer golf balls that exhibit low spin rate.
Various approaches have been taken to strike a balance between the spin rate and the playing characteristics of golf balls. For example, additional core layers, such as intermediate core and cover layers are added to the solid core golf balls in an attempt to improve the playing characteristics of the ball. These multi-layer solid core balls include multi-layer core constructions, multi-layer cover constructions and combinations thereof. In a golf ball with a multi-layer core, the principal source of resiliency is the multi-layer core. In a golf ball with a multi-layer cover and single-layer core, the principal source of resiliency is the single-layer core.
In addition, varying the materials, density or specific gravity among the multiple layers of the golf ball controls the spin rate. In general, the total weight of a golf ball has to conform to weight limits set by the United States Golf Association (“USGA”). Although the total weight of the golf ball is controlled, the distribution of weight within the ball can vary. Redistributing the weight or mass of the golf ball either toward the center of the ball or toward the outer surface of the ball changes the dynamic characteristics of the ball at impact and in flight. Specifically, if the density is shifted or redistributed toward the center of the ball, the moment of inertia of the golf ball is reduced, and the initial spin rate of the ball as it leaves the golf club increases as a result of the higher resistance from the golf ball's moment of inertia. Conversely, if the density is shifted or redistributed toward the outer surface of the ball, the moment of inertia is increased, and the initial spin rate of the ball as it leaves the golf club would decrease as a result of the higher resistance from the golf ball's moment of inertia.
The redistribution of weight within the golf ball is typically accomplished by adding fillers to one or more of the core or cover layers of the golf ball. Conventional fillers include the high specific gravity fillers, such as metal or metal alloy powders, metal oxide, metal stearates, particulates, and carbonaceous materials and low specific gravity fillers, such as hollow spheres, microspheres and foamed particles. However, the addition of fillers may adversely interfere with the resiliency of the polymers used in golf balls and thereby the coefficient of restitution of the golf balls.
Prior art golf balls have multiple core layers to provide desired playing characteristics. For example, U.S. Pat. No. 5,184,828 claims to provide a golf ball having two core layers configured to provide superior rebound characteristics and carry distance, while maintaining adequate spin rate. More particularly, the patent teaches an inner core and an outer layer and controlling the hardness distribution in the outer layer and in the inner core in such a way that the golf ball has a maximum hardness at the outer site of the inner core. The patent alleges that such a distribution of hardness in the core assembly allows high energy to accumulate at the interface region where the hardness is at a maximum. The patent further claims that the energy of the club face is efficiently delivered to the maximum hardness region and transferred toward the inner core, resulting in a high rebound coefficient. However, since golf balls having hard cores and soft covers provide the most spin, the distribution taught by this patent would result in maximum core hardness at the interface when hit by a driver. Therein the ball has a relatively high driver spin rate and not very good distance. Since the ball in this patent has a softer outer core layer, the ball should have a lower spin rate for shorter shots such as an eight iron, where spin is more desirable. Thus, the ball taught by this patent appears to have many disadvantages.
U.S. Pat. No. 6,786,838 of Sullivan et al. discloses golf balls having at least three core layers (and up to six core layers) wherein the thickness of each core layer is at least twice as thick as an adjacent outer core layer and each core layer having a different hardness. The core layers have either progressively increasing or decreasing hardness from the innermost core layer to the outermost core layer.
However, none of these references discloses a multi-layered core golf ball wherein each core layer has a plurality of hardnesses and a hardness gradient (positive, negative or a combination) within each respective core layer in addition to a hardness gradient as between core layers.
Co-pending related U.S. patent application Ser. Nos. 12/469,258, 12/469,312, 12/492,514 and 12/492,570, incorporated herein by reference, disclose and claim golf balls having single layer cores comprising different regions of varying hardness within the single layer core. The present invention extends this to the multi-layer core golf ball in order to reduce or eliminate the increased manufacturing costs and difficulty which often result when the properties of inner core layers are undesirably altered or deteriorated as outer core layers are cured or otherwise mounted or formed around the inner core layer by applying heat. The inventive plurality of hardnesses and hardness gradient within each layer of the multi-layered golf balls of the present invention therefore provide and optimize all of the benefits of a multi-layer core golf ball meanwhile reducing and minimizing the number of core layers heretofore necessary in order to achieve and optimize those benefits.
SUMMARY OF THE INVENTION
A multi-layered core golf ball wherein each core layer comprises its own hardness gradient (positive, negative or a combination) in addition to an overall hardness gradient from one core layer to the next. The inventive golf balls of the invention may also include at least a cover layer surrounding the multi-layer core.
Section I:
In a first embodiment, the golf ball comprises a two layer core and a cover disposed about the two layer core. The two layer core comprises an inner core layer and an outer core layer disposed about the inner core layer. The inner core layer comprises a geometric center and a first outer surface. The inner core layer is formed from a substantially homogenous formulation, comprises a diameter of about 30 mm or lower, and has a plurality of hardnesses of from about 50 Shore C to about 80 Shore C. The geometric center comprises a first hardness and the first outer surface comprises a second hardness wherein the first hardness is different than the second hardness to define a positive or negative hardness gradient of about 20 Shore C or lower. The outer core layer comprises an inner surface and a second outer surface. The outer core layer is formed from a substantially homogenous formulation, comprises a thickness of about 10 mm or lower and has a plurality of hardnesses of from about 50 Shore C to about 80 Shore C. The inner surface comprises a third hardness and the second outer surface comprises a fourth hardness, wherein the fourth hardness is less than the third hardness to define a negative hardness gradient of about 15 Shore C or lower. The outer core layer further comprises a fifth hardness disposed between the inner surface and the second outer surface in a region extending between about 10% and about 90% of the distance from the inner surface to the second outer surface, wherein the fifth hardness is greater than the third hardness and the fourth hardness. Finally, the fourth hardness is less than the first hardness to define a negative hardness gradient of about 15 Shore C or lower.
As used herein, the phrase “plurality of hardnesses” includes the first, second, third, fourth and/or fifth hardnesses within the inner core and outer core layers as well as any additional hardnesses which may further define regions of varying hardness within each core layer as well as between core layers.
The first embodiment may alternatively include any combination of the following elements: The third hardness may be similar to the first hardness; the third hardness may be different from the second hardness to define a positive or negative hardness gradient; the fifth hardness may be disposed between the inner surface and the second outer surface in a region extending radially from the geometric center about 13 mm to about 20 mm; the diameter of the inner core layer may be about 26 mm or less; the first hardness may be greater than the second hardness to define a negative hardness gradient of about 15 Shore C or lower; the first hardness may be less than the second hardness to define a positive hardness gradient of about 15 Shore C or lower; the fourth hardness may be less than the third hardness to define a negative hardness gradient of about 10 Shore C or lower; the fourth hardness may be less than the first hardness to define a negative hardness gradient of about 10 Shore C or lower; and the plurality of hardnesses of the inner core layer and the outer core layer may range from about 55 Shore C to about 75 Shore C.
In a second embodiment, the dual layer core differs from that of the first embodiment at least in that: the fourth hardness is greater than the third hardness to define a positive hardness gradient of about 15 Shore C or lower or the fourth hardness is greater than the third hardness to define a positive hardness gradient of about 10 Shore C or lower; the fifth hardness is less than the third hardness and the fourth hardness; the fourth hardness is greater than the first hardness to define a positive hardness gradient of about 15 Shore C or lower or the fourth hardness is greater than the first hardness to define a positive hardness gradient of about 10 Shore C or lower.
In a third embodiment, the golf ball comprises a two layer core and a cover disposed about the two layer core. The two layer core comprises an inner core layer and an outer core layer disposed about the inner core layer. The inner core layer comprises a geometric center and a first outer surface. The inner core layer is formed from a substantially homogenous formulation, comprises a diameter of about 30 mm or lower, and has a plurality of hardnesses of from about 30 Shore D to about 60 Shore D. The geometric center comprises a first hardness and the first outer surface comprises a second hardness wherein the first hardness is different than the second hardness to define a positive or negative hardness gradient of about 15 Shore D or lower. The outer core layer comprises an inner surface and a second outer surface. The outer core layer is formed from a substantially homogenous formulation, comprises a thickness of about 10 mm or lower and has a plurality of hardnesses of from about 30 Shore D to about 60 Shore D. The inner surface comprises a third hardness and the second outer surface comprises a fourth hardness, wherein the fourth hardness is less than the third hardness to define a negative hardness gradient of about 15 Shore D or lower. The outer core layer further comprises a fifth hardness disposed between the inner surface and the second outer surface in a region extending between about 10% and about 90% of the distance from the inner surface to the second outer surface, wherein the fifth hardness is greater than the third hardness and the fourth hardness. Finally, the fourth hardness is less than the first hardness to define a negative hardness gradient of about 12 Shore D or lower.
The third embodiment may alternatively include any combination of the following elements: The third hardness may be similar to the first hardness; the third hardness may be different from the second hardness to define a positive or negative hardness gradient; the fifth hardness may be disposed between the inner surface and the second outer surface in a region extending radially from the geometric center about 13 mm to about 20 mm; the diameter of the inner core layer may be about 26 mm or less; the first hardness may be greater than the second hardness to define a negative hardness gradient of about 12 Shore D or lower; the first hardness may be less than the second hardness to define a positive hardness gradient of about 12 Shore D or lower; the fourth hardness may be less than the third hardness to define a negative hardness gradient of about 10 Shore D or lower; the fourth hardness may be less than the first hardness to define a negative hardness gradient of about 10 Shore D or lower; and the plurality of hardnesses of the inner core layer and the outer core layer may range from about 30 Shore D to about 60 Shore D.
In a fourth embodiment, the dual layer core differs from that of the third embodiment at least in that: the fourth hardness is greater than the third hardness to define a positive hardness gradient of about 15 Shore D or lower; the fifth hardness is less than the third hardness and the fourth hardness; and the fourth hardness is greater than the first hardness to define a positive hardness gradient of about 12 Shore D or lower.
In the third and fourth embodiments, the plurality of hardnesses of the inner core layer and the outer core layer may alternatively range from about 25 Shore D to about 45 Shore D.
In embodiments one through four, where the geometric center comprises a first hardness and the first outer surface comprises a second hardness wherein the first hardness is different than the second hardness to define a positive hardness gradient of about 20 Shore C or lower, the inner core layer may comprise zinc diacrylate in an amount of from about 25 phr to about 35 phr. Conversely, where the geometric center comprises a first hardness and the first outer surface comprises a second hardness wherein the first hardness is different than the second hardness to define a negative hardness gradient of about 20 Shore C or lower, the inner core layer may comprise zinc diacrylate in an amount of from about 30 phr to about 40 phr.
In embodiments one through four, the outer core layer may comprise zinc diacrylate in an amount of from about 25 phr to about 40 phr.
In embodiments one through four, the inner core layer may comprise antioxidant in an amount of 1.0 phr or less.
In embodiments one and three, the outer core layer may comprise antioxidant in an amount of from about 0.2 phr to about 1.2 phr. In embodiments two and four, the outer core layer comprises no antioxidant.
In embodiments one through four, where the geometric center comprises a first hardness and the first outer surface comprises a second hardness wherein the first hardness is different than the second hardness to define a positive hardness gradient of about 20 Shore C or lower, the inner core layer may comprise peroxide in an amount of from about 0.5 phr to about 1.0 phr. Alternatively, where the geometric center comprises a first hardness and the first outer surface comprises a second hardness wherein the first hardness is different than the second hardness to define a negative hardness gradient of about 20 Shore C or lower, the inner core layer may comprise peroxide in an amount of from about 0.5 phr to about 1.2 phr.
In embodiments one and three, the outer core layer may comprise peroxide in an amount of from about 0.5 phr to about 1.2 phr. In embodiments two and four, the outer core layer may comprise peroxide in an amount of from about 0.5 phr to about 1.5 phr.
In embodiments one through four, the inner core layer may comprise polybutadiene in an amount of about 100 phr and the outer core layer may comprise polybutadiene in an amount of from about 85 phr to about 100 phr.
In embodiments one through four, where the geometric center comprises a first hardness and the first outer surface comprises a second hardness wherein the first hardness is different than the second hardness to define a positive hardness gradient of about 20 Shore C or lower, the ratio of antioxidant to initiator for the inner core layer may be about 2.5 or less. In embodiments one through four, where the geometric center comprises a first hardness and the first outer surface comprises a second hardness wherein the first hardness is different than the second hardness to define a negative hardness gradient of about 20 Shore C or lower, the ratio of antioxidant to initiator for the inner core layer may be about 4.8 or less.
In embodiments one and three, the ratio of antioxidant to initiator for the outer core layer may be from about 0.33 to about 4.8. In embodiments two and four, there is no ratio of antioxidant to initiator for the outer core layer since the outer core layer does not comprise an antioxidant.
In embodiments one through four above, the inner core layer and outer core layer may each comprise zinc oxide in an amount of from about 5 phr to about 10 phr.
Additionally, the inner core layer and outer core layer may each comprise trans polyisoprene in an amount of about 15 phr or lower. Furthermore, the inner core layer and outer core layer may each comprise zinc pentachlorothiophenol in an amount of about 3 phr or less. Moreover, the inner core layer and outer core layer may each comprise regrind in an amount of from about 10 phr to about 30 phr.
Barium sulfate may be included in each core layer in an amount sufficient to target a desired specific gravity.
Section II:
In a first embodiment, the golf ball comprises a two layer core and a cover disposed about the two layer core. The two layer core comprises an inner core layer and an outer core layer disposed about the inner core layer. The inner core layer comprises a geometric center and a first outer surface. The inner core layer is formed from a substantially homogenous formulation, comprises a diameter of about 30 mm or lower and has a plurality of hardnesses of from about 40 Shore C to about 85 Shore C. The geometric center comprises a first hardness and the first outer surface comprises a second hardness wherein the second hardness is greater than the first hardness to define a positive hardness gradient of about 20 Shore C or greater. The outer core layer comprises an inner surface and a second outer surface. The outer core layer is formed from a substantially homogenous formulation, comprises a thickness of about 10 mm or lower and has a plurality of hardnesses of from about 65 Shore C to about 95 Shore C. The inner surface comprises a third hardness and the second outer surface comprises a fourth hardness wherein the fourth hardness is greater than the third hardness to define a positive hardness gradient of about 20 Shore C or lower. The outer core layer further comprises a fifth hardness disposed between the inner surface and the second outer surface in a region between about 10% and about 90% of the distance from the inner surface to the second outer surface, wherein the fifth hardness is greater than the third hardness and the fourth hardness. Finally, the fourth hardness is greater than the first hardness to define a positive hardness gradient of about 30 Shore C or greater.
The first embodiment may alternatively include the following elements: The third hardness may be similar to the second hardness; the fifth hardness may be disposed between the inner surface and the second outer surface in a region extending radially from about 13 mm to about 20 mm from the geometric center; the diameter of the inner core layer may be about 26 mm or lower; the second hardness is greater than the first hardness to define a positive hardness gradient of about 30 Shore C or greater; the fourth hardness is greater than the third hardness to define a positive hardness gradient of about 10 Shore C or lower; the fourth hardness is greater than the first hardness to define a positive hardness gradient of about 35 Shore C or greater; and the plurality of hardnesses of the inner core layer and outer core layer may also range from about 50 Shore C to about 80 Shore C and from about 75 Shore C to about 95 Shore C, respectively.
In a second embodiment, the dual layer core differs from that of the first embodiment at least in that: the fourth hardness is less than the third hardness to define a negative hardness gradient of about 20 Shore C or lower or the fourth hardness is less than the third hardness to define a negative hardness gradient of about 10 Shore C or lower; the fifth hardness is less than the third hardness and the fourth hardness; the fourth hardness is greater than the first hardness to define a positive hardness gradient of about 20 Shore C or greater or the fourth hardness is greater than the first hardness to define a positive hardness gradient of about 25 Shore C or greater; the second hardness is greater than the first hardness to define a positive hardness gradient of about 30 Shore C or greater.
In a third embodiment, the inner core layer has a plurality hardnesses of from about 25 Shore D to about 60 Shore D and the second hardness is greater than the first hardness to define a positive hardness gradient of about 20 Shore D or greater. The outer core layer in this embodiment has a plurality hardnesses of from about 40 Shore D to about 66 Shore D. The relative outer core layer hardnesses are as follows: the fourth hardness is greater than the third hardness to define a positive hardness gradient of about 15 Shore D or lower; the fifth hardness is greater than the third hardness and the fourth hardness; the third hardness is substantially the same as the second hardness; and the fourth hardness is greater than the first hardness to define a positive hardness gradient of about 25 Shore D or greater.
The third embodiment may alternatively include the following elements: The third hardness may be similar to the second hardness; the fifth hardness may be disposed between the inner surface and the second outer surface in a region extending radially from about 13 mm to about 20 mm from the geometric center; the diameter of the inner core layer may be about 26 mm or lower; the second hardness may be greater than the first hardness to define a positive hardness gradient of about 25 Shore D or greater; the fourth hardness may be greater than the first hardness to define a positive hardness gradient of about 30 Shore D or greater; and the plurality of hardnesses of the inner core layer and the outer core layer may also range from about 20 Shore D to about 50 Shore D and from about 45 Shore D to about 60 Shore D, respectively.
In a fourth embodiment, the dual layer core differs from that of the third embodiment at least that: the fourth hardness is less than the third hardness to define a negative hardness gradient of about 15 Shore D or lower; the fifth hardness is less than the third hardness and the fourth hardness; and the fourth hardness is greater than the first hardness to define a positive hardness gradient of about 20 Shore D or greater or the fourth hardness may be greater than the first hardness to define a positive hardness gradient of about 25 Shore D or greater.
In the first and third embodiments, the inner core layer may comprise zinc diacrylate in an amount of from about 35 phr to about 45 phr and the outer core layer comprises zinc diacrylate in an amount of from about 39 phr to about 45 phr.
In the second and fourth embodiments, the inner core layer may comprise zinc diacrylate in an amount of from about 35 phr to about 45 phr and the outer core layer comprises zinc diacrylate in an amount of from about 35 phr to about 42 phr.
In each embodiment above, the inner core layer does not comprise antioxidant. However, other embodiments are envisioned in which the inner core layer may comprise antioxidant. In each embodiment, the outer core layer may comprise antioxidant in an amount of from about 0.2 phr to about 1.0 phr.
In each embodiment above, the inner core layer may comprise peroxide in an amount of about 1.2 phr or less. In another embodiment, however, the inner core layer may comprise peroxide in an amount of about 2.0 phr or less.
In embodiments one and three above, the outer core may comprise peroxide in an amount of from about 0.8 phr to about 1.5 phr. In embodiments two and four, the outer core layer may comprise peroxide in an amount of from about 0.6 phr to about 1.2 phr.
In each embodiment above, the inner core layer does not have a ratio of antioxidant to initiator since the inner core layer does not comprise an antioxidant. However, embodiments are envisioned wherein the inner core layer does indeed comprise a ratio of antioxidant to initiator.
In embodiments one and three, the ratio of antioxidant to initiator for the outer core layer may be from about 0.27 to about 2.5. In embodiments two and four, the ratio of antioxidant to initiator for the outer core layer may be from about 0.33 to about 3.33.
In embodiments one through four, the inner core layer and the outer core layer may each comprise zinc oxide in an amount of from about 5 phr to about 10 phr. Additionally, the inner core layer may comprise polybutadiene in an amount of about 100 phr and the outer core layer may comprise polybutadiene in an amount of from about 85 phr to about 100 phr. Furthermore, the inner core layer and the outer core layer may each comprise trans polyisoprene in an amount of about 15 phr or lower. Moreover, the inner core layer and the outer core layer may each comprise zinc pentachlorothiophenol in an amount of about 3 phr or less. Meanwhile, the inner core layer and the outer core layer may each comprise regrind in an amount of from about 10 phr to about 30 phr.
In each embodiment, barium sulfate may be included in each core layer in an amount sufficient to target a desired specific gravity.
Examples of additional embodiments are as follows. The outer core layer may comprise antioxidant in an amount of from about 0.2 phr to about 2.0 phr. The inner core layer may comprises peroxide in an amount of from about 0.2 phr to about 2.0 phr and the outer core may comprise peroxide in an amount of from about 0.3 phr to about 2.5 phr. The ratio of antioxidant to peroxide for the outer core layer may be about 2.5 or less.
Section III:
In a first embodiment, the golf ball comprises a two layer core and a cover disposed about the two layer core. The two layer core comprises an inner core layer and an outer core layer disposed about the inner core layer. The inner core layer comprises a geometric center and a first outer surface. The inner core layer is formed from a substantially homogenous formulation, comprises a diameter of about 30 mm or lower, and has a plurality of hardnesses of from about 60 Shore C to about 85 Shore C. The geometric center comprises a first hardness and the first outer surface comprises a second hardness wherein the second hardness is greater than the first hardness to define a positive hardness gradient of from about 5 Shore C to about 20 Shore C.
The outer core layer comprises an inner surface and a second outer surface. The outer core layer is formed from a substantially homogenous formulation, comprises a thickness of about 10 mm or lower, and has a plurality of hardnesses of from about 60 Shore C to about 95 Shore C. The inner surface comprises a third hardness and the second outer surface comprises a fourth hardness wherein the fourth hardness is greater than the third hardness to define a positive hardness gradient of about 20 Shore C or lower. The outer core layer further comprises a fifth hardness disposed between the inner surface and the second outer surface in a region extending between about 10% and about 90% of the distance from the inner surface to the second outer surface, wherein the fifth hardness is greater than the third hardness and the fourth hardness. Finally, the fourth hardness is greater than the first hardness to define a positive hardness gradient of about 30 Shore C or lower.
The first embodiment may alternatively include the following elements: The third hardness may be similar to the second hardness; the fifth hardness may be disposed between the inner surface and the second outer surface in a region extending radially from about 13 mm to about 20 mm from the geometric center; the diameter of the inner core layer may be about 26 mm or lower; the fourth hardness may be greater than the third hardness to define a positive hardness gradient of about 10 Shore C or lower; the fourth hardness may be greater than the first hardness to define a positive hardness gradient of about 25 Shore C or lower; and the inner core layer and outer core layer may have a plurality of hardnesses of from about 65 Shore C to about 75 Shore C and from about 70 shore C to about 85 Shore C, respectively.
In a second embodiment, the dual layer core differs from that of the first embodiment at least in that: the fourth hardness is less than the third hardness to define a negative hardness gradient of about 20 Shore C or lower or the fourth hardness may be less than the third hardness to define a negative hardness gradient of about 10 Shore C or lower; the fifth hardness is less than the third hardness and the fourth hardness; and the fourth hardness is greater than the first hardness to define a positive hardness gradient of about 18 Shore C or lower or the fourth hardness may be greater than the first hardness to define a positive hardness gradient of about 15 Shore C or lower.
In a third embodiment, the inner core layer has a plurality of hardnesses of from about 35 Shore D to about 58 Shore D and the second hardness is greater than the first hardness to define a positive hardness gradient of from about 3 Shore D to about 20 Shore D. The outer core layer has a plurality of hardnesses of from about 40 Shore D to about 69 Shore D, and the relative outer core layer hardnesses are as follows: the fourth hardness is greater than the third hardness to define a positive hardness gradient of about 15 Shore D or lower; the fifth hardness is greater than the third hardness and the fourth hardness; and the fourth hardness is greater than the first hardness to define a positive hardness gradient of about 30 Shore D or lower.
The third embodiment may alternatively include the following elements: The third hardness may be similar to the second hardness; the fifth hardness may be disposed between the inner surface and the second outer surface in a region extending radially from about 13 mm to about 20 mm from the geometric center; the second hardness may be greater than the first hardness to define a positive hardness gradient of from about 5 Shore D to about 15 Shore D; the fourth hardness may be greater than the third hardness to define a positive hardness gradient of about 10 Shore D or lower; the fourth hardness may be greater than the first hardness to define a positive hardness gradient of about 22 Shore D or lower; and the inner core layer and outer core layer may also have a plurality of hardnesses of from about 35 to about 45 Shore D and from about 40 Shore D to about 56 Shore D, respectively.
In a fourth embodiment, the dual layer core differs from that of the third embodiment at least in that: the second hardness is greater than the first hardness to define a positive hardness gradient of from about 5 Shore D to about 15 Shore D; the fourth hardness is less than the third hardness to define a negative hardness gradient of about 15 Shore D or lower or the fourth hardness is less than the third hardness to define a negative hardness gradient of about 10 Shore D or lower; the fifth hardness is less than the third hardness and the fourth hardness; and the fourth hardness is greater than the first hardness to define a positive hardness gradient of about 20 Shore D or lower or the fourth hardness is greater than the first hardness to define a positive hardness gradient of about 18 Shore D or lower.
In the first and third embodiments, the inner core layer may comprise zinc diacrylate in an amount of from about 35 phr to about 45 phr and the outer core layer may comprise zinc diacrylate in an amount of from about 39 phr to about 45 phr.
In the second and fourth embodiments, the inner core layer may comprise zinc diacrylate in an amount of from about 35 phr to about 45 phr and the outer core layer may comprise zinc diacrylate in an amount of from about 35 phr to about 42 phr.
In each of the embodiments above, the inner core layer may comprise antioxidant in an amount of about 1.0 phr or less and the outer core layer may comprise an antioxidant in an amount of from about 0.2 phr to about 1.0 phr.
In each of the embodiments above, the inner core layer may comprise peroxide in an amount of from about 0.5 phr to about 1.0 phr.
In the first and third embodiments, the outer core layer may comprise peroxide in an amount of from about 0.8 phr to about 1.5 phr. In the second and fourth embodiments, the outer core layer may comprise peroxide in an amount of from about 0.6 phr to about 1.2 phr.
In each embodiment above, the ratio of antioxidant to initiator for the inner core layer may be about 2.5 or less.
In the first and third embodiments, the ratio of antioxidant to initiator for the outer core layer may be from about 0.27 to about 2.5. In the second and fourth embodiments, the ratio of antioxidant to initiator for the outer core layer may be from about 0.33 to about 3.33.
In each embodiment, the inner core layer may comprise polybutadiene in an amount of about 100 phr and the outer core layer may comprise polybutadiene in an amount of from about 85 phr to about 100 phr.
In the four embodiments above, the inner core layer and the outer core layer may each comprise zinc oxide in an amount of from about 5 phr to about 10 phr.
In the four embodiments above, the inner core layer and the outer core layer may each comprise trans polyisoprene in an amount of about 15 phr or lower.
In the four embodiments above, the inner core layer and the outer core layer may each comprise zinc pentachlorothiophenol in an amount of about 3 phr or less.
In the four embodiments above, the inner core layer and the outer core layer may each comprise regrind in an amount of from about 10 phr to about 30 phr.
In the four embodiments above, barium sulfate may be included in each core layer in an amount sufficient to target a desired specific gravity.
Examples of other embodiments are as follows. The inner core layer may comprise antioxidant in an amount of about 1.8 phr or less and the outer core layer may comprise antioxidant in an amount of from about 0.2 phr to about 2.0 phr. The inner core layer may comprise peroxide in an amount of from about 0.5 phr to about 2.0 phr and the outer core layer may comprise peroxide in an amount of from about 0.6 phr to about 2.5 phr. The ratio of antioxidant to initiator for the inner core layer may be about 2.5 or lower.
Section IV:
In a first embodiment, the golf ball comprises a two layer core and a cover disposed about the two layer core. The two layer core comprises an inner core layer and an outer core layer disposed about the inner core layer. The inner core layer comprises a geometric center and a first outer surface. The inner core layer is formed from a substantially homogenous formulation, comprises a diameter of about 30 mm or lower, and has a plurality of hardnesses of from about 50 Shore C to about 90 Shore C. The geometric center comprises a first hardness and the first outer surface comprises a second hardness wherein the first hardness is greater than the second hardness to define a negative hardness gradient of about 20 Shore C or greater. The outer core layer comprises an inner surface and a second outer surface. The outer core layer is formed from a substantially homogenous formulation, comprises a thickness of about 10 mm or lower, and has a plurality of hardnesses of from about 50 Shore C to about 95 Shore C. The inner surface comprises a third hardness and the second outer surface comprises a fourth hardness wherein the fourth hardness is greater than the third hardness to define a positive hardness gradient of about 20 Shore C or greater. The outer core layer further comprises a fifth hardness disposed between the inner surface and the second outer surface in a region extending between about 10% and about 90% of the distance from the inner surface to the second outer surface, wherein the fifth hardness is greater than the first hardness, the third hardness and the fourth hardness. Finally, the fourth hardness is similar to or less than the first hardness.
The first embodiment may alternatively include the following elements: The third hardness may be similar to the second hardness; the fifth hardness may be disposed between the inner surface and the second outer surface in a region extending radially from about 13 mm to about 20 mm from the geometric center; the diameter of the inner core layer may be about 26 mm or lower; the first hardness may be greater than the second hardness to define a negative hardness gradient of about 20 Shore C or greater; and the fourth hardness may be greater than the third hardness to define a positive hardness gradient of about 25 Shore C or greater.
In a second embodiment, the dual layer core differs from that of the first embodiment at least in that: the plurality of hardnesses of the outer core layer is from about 50 Shore C to about 80 Shore C; the fifth hardness is similar to or less than the first hardness and is greater than the third hardness; the fourth hardness is greater than the third hardness to define a positive hardness gradient of about 15 Shore C or lower or about 10 Shore C or lower; the fourth hardness is less than the first hardness.
In a third embodiment, the dual layer core differs from that of the first embodiment at least in that: the plurality of hardnesses of the outer core layer is from about 40 Shore C to about 75 Shore C; the fourth hardness is similar to or less than the third hardness; and the fifth hardness is less than the third hardness and the fourth hardness.
Alternatively, in the first embodiment, the plurality of hardnesses of the inner core layer and the outer core layer may range from about 55 Shore C to about 85 Shore C and from about 55 Shore C to about 90 Shore C, respectively. In the second embodiment, the plurality of hardnesses of the inner core layer and the outer core layer may each also range from about 55 Shore C to about 85 Shore C. In the third embodiment, the plurality of hardnesses of the inner core layer and the outer core layer may additionally range from about 55 Shore C to about 85 Shore C and from about 50 Shore C to about 85 Shore C, respectively.
In a fourth embodiment, the golf ball comprises a two layer core and a cover disposed about the two layer core. The two layer core comprises an inner core layer and an outer core layer disposed about the inner core layer. The inner core layer comprises a geometric center and a first outer surface. The inner core layer is formed from a substantially homogenous formulation, comprises a diameter of about 30 mm or lower, and has a plurality of hardnesses of from about 30 Shore D to about 68 Shore D. The geometric center comprises a first hardness and the first outer surface comprises a second hardness, wherein the first hardness is greater than the second hardness to define a negative hardness gradient of about 20 Shore D or greater. The outer core layer comprises an inner surface and a second outer surface. The outer core layer is formed from a substantially homogenous formulation, comprises a thickness of about 10 mm or lower, and has a plurality of hardnesses of from about 30 Shore D to about 68 Shore D. The inner surface comprises a third hardness and the second outer surface comprises a fourth hardness, wherein the fourth hardness is greater than the third hardness to define a positive hardness gradient of about 20 Shore D or greater. The outer core layer further comprises a fifth hardness disposed between the inner surface and the second outer surface in a region extending between about 10% and about 90% of the distance from the inner surface to the second outer surface, wherein the fifth hardness is greater than the first hardness, the third hardness and the fourth hardness. Finally, the fourth hardness is similar to or less than the first hardness.
The fourth embodiment may alternatively include the following elements: The third hardness may be similar to the second hardness; the fifth hardness may be disposed between the inner surface and the second outer surface in a region extending radially from about 13 mm to about 20 mm from the geometric center; the diameter of the inner core layer may be about 26 mm or lower; the first hardness may be greater than the second hardness to define a negative hardness gradient of about 25 Shore D or greater; and the fourth hardness may be greater than the third hardness to define a positive hardness gradient of about 25 Shore D or greater.
In a fifth embodiment, the dual layer core differs from that of the fourth embodiment at least in that: The outer core layer has a plurality of hardnesses of from about 30 Shore D to about 55 Shore D; the fourth hardness is greater than the third hardness to define a positive hardness gradient of about 10 Shore D or lower; the fifth hardness is similar to or less than the first hardness; and the fourth hardness is less than the first hardness.
In a sixth embodiment, the dual layer core differs from that of the fourth and fifth embodiments at least in that: the plurality of hardnesses of the outer core layer is from about 25 Shore D to about 45 Shore D; the fourth hardness is similar to or less than the third hardness; and the fifth hardness is less than the third hardness and the fourth hardness.
Alternatively, in the fourth embodiment, the plurality of hardnesses of the inner core layer and the outer core layer may range from about 25 Shore D to about 56 Shore D and from about 25 Shore D to about 60 Shore D, respectively. In the fifth embodiment, the plurality of hardnesses of the inner core layer and the outer core layer may each also range from about 25 Shore D to about 56 Shore D. In the sixth embodiment, the plurality of hardnesses of the inner core layer and the outer core layer may range from about 25 Shore D to about 56 Shore D and from about 20 Shore D to about 56 Shore D, respectively.
In embodiments one through six, the inner core layer may comprise antioxidant in an amount of from about 0.2 phr to about 1.2 phr. Additionally, the inner core layer may comprise peroxide in an amount of from about 0.5 phr to about 1.2 phr. The resulting ratio of antioxidant to initiator of the inner core layer may be from about 0.33 to about 4.8.
In embodiments one and four, the outer core layer may not comprise any antioxidant. However, it is envisioned that the formulation for embodiments one and four may be modified so that the outer core layer does indeed comprise antioxidant.
In embodiments two and five, the outer core layer may comprise antioxidant in an amount of about 1.0 phr or less.
In embodiments three and six, the outer core layer may comprise antioxidant in an amount of from about 0.2 phr to about 1.2 phr.
The inner and outer core may comprise peroxide as disclosed in Table I herein, including either a single peroxide or a combination of peroxides.
In embodiments one and six, the ratio of antioxidant to initiator of the outer core layer is zero where the outer core layer does not comprise any antioxidant. In embodiments two and five, the ratio of antioxidant to initiator of the outer core layer may be about 10.0 or less. In embodiments three and six, the ratio of antioxidant to initiator of the outer core layer may be from about 0.33 to about 4.8.
In each of embodiments one through six, the inner core layer may comprise polybutadiene in an amount of about 100 phr and the outer core layer may comprise polybutadiene in an amount of from about 85 phr to about 100 phr. Furthermore, the inner core layer may comprise zinc diacrylate in an amount of from about 40 phr to about 50 phr and the outer core layer may comprise zinc diacrylate in an amount of from about 30 phr to about 45 phr. Additionally, the inner core layer and the outer core layer may each comprise zinc oxide in an amount of from about 5 phr to about 10 phr. Moreover, the inner core layer and the outer core layer may each comprise zinc pentachlorothiophenol in an amount of about 3 phr or less. Further, the inner core layer and the outer core layer may each comprise regrind in an amount of from about 10 phr to about 30 phr. In addition, the inner core layer and the outer core layer may each comprise trans polyisoprene in an amount of about 15 phr or less. Barium sulfate may be included in each core layer in an amount sufficient to target a desired specific gravity.
In an alternative embodiment, the inner core layer and the outer core layer each comprises peroxide in an amount of from about 0.2 phr to about 3.0 phr and antioxidant in an amount of about 2.5 phr or less.
Section V:
In a first embodiment, the golf ball comprises a two layer core and a cover disposed about the two layer core. The two layer core comprises an inner core layer and an outer core layer disposed about the inner core layer. The inner core layer comprises a geometric center and a first outer surface. The inner core layer is formed from a substantially homogenous formulation, comprises a diameter of about 30 mm or lower, and has a plurality of hardnesses of from about 50 Shore C to about 80 Shore C. The geometric center comprises a first hardness and the first outer surface comprises a second hardness, wherein the first hardness is greater than the second hardness to define a negative hardness gradient about 20 Shore C or less. The outer core layer comprises an inner surface and a second outer surface. The outer core layer is formed from a substantially homogenous formulation, comprises a thickness of about 10 mm or lower, and has a plurality of hardnesses of from about 50 Shore C to about 90 Shore C. The inner surface comprises a third hardness and the second outer surface comprises a fourth hardness, wherein the fourth hardness is greater than the third hardness. The outer core layer further comprises a fifth hardness disposed between the inner surface and the second outer surface in a region extending between about 10% and about 90% of the distance from the inner surface to the second outer surface, wherein the fifth hardness is greater than the first hardness, the third hardness and the fourth hardness. Finally, the fourth hardness is greater than the first hardness to define a two layer core having a positive hardness gradient of less than about 20 Shore C.
The first embodiment may alternatively include any combination of the following elements: The third hardness may be similar to the first hardness; the fifth hardness may be disposed between the inner surface and the second outer surface in a region extending radially from the geometric center about 13 mm to about 20 mm; the diameter of the inner core layer may be about 26 mm or less; the first hardness may be greater than the second hardness to define a negative hardness gradient of about 15 Shore C or less; the fourth hardness may be greater than the first hardness to define a two layer core having a positive hardness gradient of less than about 15 Shore C.
In a second embodiment, the dual layer core differs from that of the first embodiment at least in that: The outer core has a plurality of hardnesses of from about 50 Shore C to about 80 Shore C, the fifth hardness is greater than the third hardness and the fourth hardness and similar to the first hardness; and the fourth hardness is less than the first hardness to define a two layer core having a negative hardness gradient of less than about 10 Shore C or the fourth hardness is less than the first hardness to define a two layer core having a negative hardness gradient of less than about 7 Shore C.
In a third embodiment, the dual layer core differs from that of the first embodiment at least in that: The outer core layer has a plurality of hardnesses of from about 45 Shore C to about 80 Shore C, the fifth hardness is less than the third hardness and the fourth hardness, and the fourth hardness is less than the first hardness to define a two layer core having a negative hardness gradient of no greater than about 20 Shore C or the fourth hardness is less than the first hardness to define a two layer core having a negative hardness gradient of no greater than about 15 Shore C.
In a fourth embodiment, the dual layer core differs from that of the first embodiment at least in that: The outer core layer has a plurality of hardnesses of from about 50 Shore C to about 80 Shore C; the first hardness is greater than the second hardness to define a negative hardness gradient of about 23 Shore C or less or the first hardness is greater than the second hardness to define a negative hardness gradient of about 18 Shore C or less; the fourth hardness is similar to the first hardness; and there is no fifth hardness as defined in the first embodiment.
In a fifth embodiment, the dual layer core differs from that of the first embodiment at least in that: The outer core layer has a plurality of hardnesses of from about 45 Shore C to about 80 Shore C, the fourth hardness is less than the first hardness to define a two layer core having a negative hardness gradient of no greater than about 15 Shore C or the fourth hardness is greater than the first hardness by 5 Shore C or less; and the fifth hardness is less than the third hardness and the fourth hardness.
Alternatively, in the first embodiment the plurality of hardnesses of the inner core layer and the outer core layer may range from about 45 Shore C to about 75 Shore C and from about 45 Shore C to about 80 Shore C, respectively. In the second and fourth embodiments, the plurality of hardnesses of the inner core layer and the outer core layer may each also range from about 45 Shore C to about 75 Shore C. In the third and fifth embodiments, the plurality of hardnesses of the inner core layer and the outer core layer may additionally range from about 55 Shore C to about 85 Shore C and from about 50 Shore C to about 85 Shore C, respectively.
In a sixth embodiment, the golf ball comprises a two layer core and a cover disposed about the two layer core. The two layer core comprises an inner core layer and an outer core layer disposed about the inner core layer. The inner core layer comprises a geometric center and a first outer surface. The inner core layer is formed from a substantially homogenous formulation, comprises a diameter of about 30 mm or less, and has a plurality of hardnesses of from about 25 Shore D to about 55 Shore D. The geometric center comprises a first hardness and the first outer surface comprises a second hardness, wherein the first hardness is greater than the second hardness to define a negative hardness gradient of about 20 Shore D or less.
The outer core layer comprises an inner surface and a second outer surface. The outer core layer is formed from a substantially homogenous formulation, comprises a thickness of about 10 mm or less and has a plurality of hardnesses of from about 30 Shore D to about 69 Shore D. The inner surface comprises a third hardness and the second outer surface comprises a fourth hardness, wherein the fourth hardness is greater than the third hardness. The outer core layer further comprises a fifth hardness disposed between the inner surface and the second outer surface in a region extending between about 10% and about 90% of the distance from the inner surface to the second outer surface, wherein the fifth hardness is greater than the third hardness and the fourth hardness. Finally, the fourth hardness is greater than the first hardness to define a positive hardness gradient of less than about 45 Shore D.
In a seventh embodiment, the dual layer core differs from that of the first embodiment at least in that: The outer core layer comprises a plurality of hardnesses of from about 30 Shore D to about 52 Shore D, the fifth hardness is greater than the third hardness and the fourth hardness or the fifth hardness is greater than the third hardness and the fourth hardness and similar to the first hardness; and the fourth hardness is less than the first hardness to define a two layer core having a negative hardness gradient of no greater than about 10 Shore D or the fourth hardness is less than the first hardness to define a two layer core having a negative hardness gradient of no greater than about 8 Shore D.
In an eighth embodiment, the dual layer core differs from that of the first embodiment at least in that: The outer core layer comprises a plurality of hardnesses of from about 25 Shore D to about 40 Shore D; the fourth hardness is greater than the third hardness or the fourth hardness is less than the third hardness; and the fourth hardness is less than the first hardness to define a two layer core having a negative hardness gradient of from about 10 Shore D to about 25 Shore D or the fourth hardness is less than the first hardness to define a two layer core having a negative hardness gradient of from about 13 Shore D to about 21 Shore D.
In a ninth embodiment, the dual layer core differs from that of the first embodiment at least in that: The outer core layer comprises a plurality of hardnesses of from about 20 Shore D to about 55 Shore D; the first hardness is greater than the second hardness to define a negative hardness gradient of about 25 Shore D or less; the fourth hardness is similar to the first hardness or the fourth hardness is greater than the third hardness; and there is no fifth hardness as defined in the first embodiment.
In a tenth embodiment, the dual layer core differs from that of the first embodiment at least in that: The outer core layer comprises a plurality of hardnesses of from about 15 Shore D to about 50 Shore D, the fifth hardness is less than the third hardness and the fourth hardness, and the fourth hardness is less than the fourth hardness to define a two layer core having a negative gradient of no greater than about 10 Shore D or the fourth hardness is greater than the first hardness.
Alternatively, in the sixth embodiment, the plurality of hardnesses of the inner core layer and the outer core layer may range from about 25 Shore D to about 45 Shore D and from about 25 Shore D to about 58 Shore D, respectively. In the seventh and ninth embodiments, the plurality of hardnesses of the inner core layer and the outer core layer may instead range from about 25 Shore D to about 45 Shore D. Optionally, in the eighth and tenth embodiments, the plurality of hardnesses of the inner core layer and the outer core layer may range from about 25 Shore D to about 45 Shore D and from about 15 Shore D to about 45 Shore D, respectively.
In embodiments one through ten, the inner core layer may comprise antioxidant in an amount of from about 0.2 phr to about 1.2 phr. Additionally, in embodiments one through ten, the inner core layer may comprise peroxide in an amount of from about 0.5 phr to about 1.2 phr. The resulting ratio of antioxidant to initiator of the inner core layer in these embodiments may be from about 0.33 to about 4.8
In embodiments one and six, the outer core layer may not comprise any antioxidant. However, it is envisioned and appreciated that the formulation for embodiments one and six may be modified such that the outer core layer does indeed comprise antioxidant.
In embodiments two and seven, the outer core layer may comprise antioxidant in an amount of about 1.0 phr or less.
In embodiments three and eight, the outer core layer may comprise antioxidant in an amount of from about 0.2 phr to about 1.2 phr.
In embodiments four and nine, the outer core layer may comprise antioxidant in an amount of 0.5 phr or less.
In embodiments five and ten, the outer core layer may comprise antioxidant in an amount of 1.0 phr or less.
In embodiments one and six, the outer core layer may comprise peroxide in an amount of from about 0.5 phr to about 1.0 phr.
In embodiments two and seven, the outer core layer may comprise peroxide in an amount of from about 0.2 phr to about 0.8 phr. Alternatively, in embodiments two and seven, the outer core layer may comprise peroxide in an amount of about 1.0 phr or less.
In embodiments three and eight, the outer core layer may comprise peroxide in an amount of from about 0.5 phr to about 1.2 phr.
In embodiments four, five, nine and ten, the outer core layer may comprise peroxide in an amount of 1.5 phr or less.
Accordingly, in embodiments one and six, the ratio of antioxidant to initiator of the outer core layer may be about 0. In embodiments two and seven, the ratio of antioxidant to initiator of the outer core layer may be about 10.0 or less. In embodiments three and eight, the ratio of antioxidant to initiator of the outer core layer may be about 0.33 to about 4.8. In embodiments four and nine, the ratio of antioxidant to initiator of the outer core layer may be 1.0 or less. Finally, in embodiments five and ten, the ratio of antioxidant to initiator of the outer core layer may be about 2.0 or less.
In each of embodiments one through ten, the inner core layer may comprise polybutadiene in an amount of about 100 phr and the outer core layer may comprise polybutadiene in an amount of from about 85 phr to about 100 phr. Additionally, for each embodiment one through ten, the inner core layer may comprise zinc diacrylate in an amount of from about 25 phr to about 35 phr and the outer core layer may comprise zinc diacrylate in an amount of from about 30 phr to about 45 phr. Furthermore, the inner core layer and the outer core layer may each comprise trans polyisoprene in an amount of about 15 phr or less. Moreover, the inner core layer and the outer core layer may each comprise zinc oxide in an amount of from about 5 phr to about 10 phr. In addition, the inner core layer and the outer core layer each comprises zinc pentachlorothiophenol in an amount of about 3 phr or less. Further, the inner core layer and the outer core layer may each comprise regrind in an amount of from about 10 phr to about 30 phr. Barium sulfate may be included in each core layer in an amount sufficient to target a desired specific gravity.
Examples of other embodiments are as follows. The inner core layer may comprise antioxidant in an amount of from about 0.2 phr to about 2.5 phr and the outer core layer may comprise antioxidant in an amount of about 1.2 phr or less. The inner core layer may comprise peroxide in an amount of from about 0.5 phr to about 2.0 phr and the outer core may comprise peroxide in an amount of from about 0.6 phr to about 2.5 phr. The ratio of antioxidant to peroxide for the inner core layer may be about 2.5 or less. The ratio of antioxidant to peroxide for the outer core layer may be about 2.0 or less.
It is preferred that the golf ball of the present invention comprise two core layers and a cover in order to maximize the benefits achieved from such a golf ball construction—namely reducing or eliminating the increased manufacturing costs and difficulty which often result when the properties of inner core layers are undesirably altered or deteriorated as outer core layers are cured or otherwise mounted or formed around the inner core layer by applying heat. However, it is recognized and envisioned that the inventive golf ball may comprise and extend to any number of core layers, intermediate layers, and/or cover layers having regions of varying hardness within and between each layer.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings which forms a part of the specification and is to be read in conjunction therewith:
FIG. 1 is a cross-sectional view of a golf ball formed according to one embodiment of the present invention;
FIG. 2 is a graph of the Shore C hardness of an inventive multi-layer core as a function of the distance from its center according to illustrative embodiments;
FIG. 3 is a graph of the Shore D hardness of an inventive multi-layer core as a function of the distance from its center according to illustrative embodiments;
FIG. 4 is a graph of the Shore C hardness of an inventive multi-layer core as a function of the distance from its center according to illustrative embodiments;
FIG. 5 is a graph of the Shore D hardness of an inventive multi-layer core as a function of the distance from its center according to illustrative embodiments;
FIG. 6 is a graph of the Shore C hardness of an inventive multi-layer core as a function of the distance from its center according to illustrative embodiments;
FIG. 7 is a graph of the Shore D hardness of an inventive multi-layer core as a function of the distance from its center according to illustrative embodiments;
FIG. 8 is a graph of the Shore C hardness of an inventive multi-layer core as a function of the distance from its center according to illustrative embodiments;
FIG. 9 is a graph of the Shore D hardness of an inventive multi-layer core as a function of the distance from its center according to illustrative embodiments;
FIGS. 10A and 11A are graphs of the Shore C hardness of an inventive multi-layer core as a function of the distance from its center according to illustrative embodiments; and
FIGS. 10B and 11B are graphs of the Shore D hardness of an inventive multi-layer core as a function of the distance from its center according to illustrative embodiments.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As briefly discussed above, each inventive core layer may have a hardness gradient defined by hardness measurements made at the surface of the inner core (or outer core layer) and radially inward toward the center of the inner core, typically at 2-mm increments. As used herein, the terms “negative” and “positive” refer to the result of subtracting the hardness value at the innermost portion of the component being measured from the hardness value at the outer surface of the component being measured. For example, if the outer surface of a core layer has a greater hardness value than its innermost surface, the hardness gradient will be deemed a “positive” gradient. Alternatively, if the inner surface of one layer of a multi-layer core has a greater hardness value than its inner surface, the hardness gradient for that core layer will be deemed a “negative” gradient.
Each region of a core layer (inner core region, or outer core region or intermediate core region) may be made from a composition including at least one thermoset base rubber, such as a polybutadiene rubber, cured with at least one peroxide and at least one reactive co-agent, which can be a metal salt of an unsaturated carboxylic acid, such as acrylic acid or methacrylic acid, a non-metallic coagent, or mixtures thereof. Preferably, a suitable antioxidant is included in the composition. An optional soft and fast agent (and sometimes a cis-to-trans catalyst), such as an organosulfur or metal-containing organosulfur compound, can also be included in the core formulation.
Other ingredients that are known to those skilled in the art may be used, and are understood to include, but not be limited to, density-adjusting fillers, process aides, plasticizers, blowing or foaming agents, sulfur accelerators, and/or non-peroxide radical sources.
The base thermoset rubber, which can be blended with other rubbers and polymers, typically includes a natural or synthetic rubber. A preferred base rubber is 1,4-polybutadiene having a cis structure of at least 40%, preferably greater than 80%, and more preferably greater than 90%.
Examples of desirable polybutadiene rubbers include BUNA® CB22 and BUNA® CB23, TAKTENE® 1203G1, 220, 221, and PETROFLEX® BRNd-40, commercially available from LANXESS Corporation; BR-1220 available from BST Elastomers Co. LTD; UBEPOL® 360L and UBEPOL® 150L and UBEPOL-BR rubbers, commercially available from UBE Industries, Ltd. of Tokyo, Japan; KINEX® 7245 and KINEX® 7265, commercially available from Goodyear of Akron, Ohio; SE BR-1220, commercially available from Dow Chemical Company; Europrene® NEOCIS® BR 40 and BR 60, commercially available from Polimeri Europa; and BR 01, BR 730, BR 735, BR 11, and BR 51, commercially available from Japan Synthetic Rubber Co., Ltd; and KARBOCHEM® ND40, ND45, and ND60, commercially available from Karbochem.
The base rubber may also comprise high or medium Mooney viscosity rubber, or blends thereof. The measurement of Mooney viscosity is defined according to ASTM D-1646.
The Mooney viscosity range is preferably greater than about 30, more preferably in the range from about 35 to about 75 and more preferably in the range from about 40 to about 60. Polybutadiene rubber with higher Mooney viscosity may also be used, so long as the viscosity of the polybutadiene does not reach a level where the high viscosity polybutadiene clogs or otherwise adversely interferes with the manufacturing machinery. It is contemplated that polybutadiene with viscosity less than about 75 Mooney can be used with the present invention.
In one embodiment of the present invention, golf ball cores made with mid- to high-Mooney viscosity polybutadiene material exhibit increased resiliency (and, therefore, distance) without increasing the hardness of the ball.
Commercial sources of suitable mid- to high-Mooney viscosity polybutadiene include Lanxess Buna CB23 (Nd-catalyzed), which has a Mooney viscosity of around 50 and is a highly linear polybutadiene, and Dow SE BR-1220 (Co-catalyzed). If desired, the polybutadiene can also be mixed with other elastomers known in the art, such as other polybutadiene rubbers, natural rubber, styrene butadiene rubber, and/or isoprene rubber in order to further modify the properties of the core. When a mixture of elastomers is used, the amounts of other constituents in the core composition are typically based on 100 parts by weight of the total elastomer mixture.
In one preferred embodiment, the base rubber comprises a transition metal polybutadiene, a rare earth-catalyzed polybutadiene rubber, or blends thereof. If desired, the polybutadiene can also be mixed with other elastomers known in the art such as natural rubber, polyisoprene rubber and/or styrene-butadiene rubber in order to modify the properties of the core. Other suitable base rubbers include thermosetting materials such as, ethylene propylene diene monomer rubber, ethylene propylene rubber, butyl rubber, halobutyl rubber, hydrogenated nitrile butadiene rubber, nitrile rubber, and silicone rubber.
Thermoplastic elastomers (TPE) many also be used to modify the properties of the core layers, or the uncured core layer stock by blending with the base thermoset rubber. These TPEs include natural or synthetic balata, or high trans-polyisoprene, high trans-polybutadiene, or any styrenic block copolymer, such as styrene ethylene butadiene styrene, styrene-isoprene-styrene, etc., a metallocene or other single-site catalyzed polyolefin such as ethylene-octene, or ethylene-butene, or thermoplastic polyurethanes (TPU), including copolymers, e.g. with silicone. Other suitable TPEs for blending with the thermoset rubbers of the present invention include PEBAX®, which is believed to comprise polyether amide copolymers, HYTREL®, which is believed to comprise polyether ester copolymers, thermoplastic urethane, and KRATON®, which is believed to comprise styrenic block copolymers elastomers. Any of the TPEs or TPUs above may also contain functionality suitable for grafting, including maleic acid or maleic anhydride.
Additional polymers may also optionally be incorporated into the base rubber. Examples include, but are not limited to, thermoset elastomers such as core regrind, thermoplastic vulcanizate, copolymeric ionomer, terpolymeric ionomer, polycarbonate, polyamides, copolymeric polyamides, polyesters, polyvinyl alcohols, acrylonitrile-butadiene-styrene copolymers, polyarylate, polyacrylate, polyphenylene ether, impact-modified polyphenylene ether, high impact polystyrene, diallyl phthalate polymer, styrene-acrylonitrile polymer (SAN) (including olefin-modified SAN and acrylonitrile-styrene-acrylonitrile polymer), styrene-maleic anhydride copolymer, styrenic copolymer, functionalized styrenic copolymer, functionalized styrenic terpolymer, styrenic terpolymer, cellulose polymer, liquid crystal polymer, ethylene-vinyl acetate copolymers, polyurea, and polysiloxane or any metallocene-catalyzed polymers of these species.
Suitable polyamides for use as an additional polymeric material in compositions within the scope of the present invention also include resins obtained by: (1) polycondensation of (a) a dicarboxylic acid, such as oxalic acid, adipic acid, sebacic acid, terephthalic acid, isophthalic acid, or 1,4-cyclohexanedicarboxylic acid, with (b) a diamine, such as ethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, or decamethylenediamine, 1,4-cyclohexanediamine, or m-xylylenediamine; (2) a ring-opening polymerization of cyclic lactam, such as ε-caprolactam or Ω-laurolactam; (3) polycondensation of an aminocarboxylic acid, such as 6-aminocaproic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, or 12-aminododecanoic acid; or (4) copolymerization of a cyclic lactam with a dicarboxylic acid and a diamine. Specific examples of suitable polyamides include NYLON 6, NYLON 66, NYLON 610, NYLON 11, NYLON 12, copolymerized NYLON, NYLON MXD6, and NYLON 46.
Suitable peroxide initiating agents include dicumyl peroxide; 2,5-dimethyl-2,5-di(t-butylperoxy)hexane; 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne; 2,5-dimethyl-2,5-di(benzoylperoxy)hexane; 2,2-bis(t-butylperoxy)-di-iso-propylbenzene; 1,1-bis(t-butylperoxy)-3,3,5-trimethyl cyclohexane; n-butyl 4,4-bis(t-butyl-peroxy)valerate; t-butyl perbenzoate; benzoyl peroxide; n-butyl 4,4′-bis(butylperoxy)valerate; di-t-butyl peroxide; or 2,5-di-(t-butylperoxy)-2,5-dimethyl hexane, lauryl peroxide, t-butyl hydroperoxide, α-αbis(t-butylperoxy)diisopropylbenzene, di(2-t-butyl-peroxyisopropyl)benzene, di-t-amyl peroxide, di-t-butyl peroxide. Commercially-available peroxide initiating agents include DICUP™ family of dicumyl peroxides (including DICUP™ R, DICUP™ 40C and DICUP™ 40KE) available from Crompton (Geo Specialty Chemicals). Similar initiating agents are available from AkroChem, Lanxess, Flexsys/Harwick and R.T. Vanderbilt. Another commercially-available and preferred initiating agent is TRIGONOX™ 265-50B from Akzo Nobel, which is a mixture of 1,1-di(t-butylperoxy)-3,3,5-trimethylcyclohexane and di(2-t-butylperoxyisopropyl)benzene. TRIGONOX™ peroxides are generally sold on a carrier compound. Additionally or alternatively, VAROX ANS may be used. Herein, the terms “peroxide initiating agents”, peroxide(s), initiating agent(s) and initiator(s) are used interchangeably.
Suitable reactive co-agents include, but are not limited to, metal salts of diacrylates, dimethacrylates, and monomethacrylates suitable for use in this invention include those wherein the metal is zinc, magnesium, calcium, barium, tin, aluminum, lithium, sodium, potassium, iron, zirconium, and bismuth. Zinc diacrylate (ZDA) is preferred, but the present invention is not limited thereto. ZDA provides golf balls with a high initial velocity. The ZDA can be of various grades of purity. For the purposes of this invention, the lower the quantity of zinc stearate present in the ZDA the higher the ZDA purity. ZDA containing less than about 20% zinc stearate is preferable. More preferable is ZDA containing about 4-8% zinc stearate. Suitable, commercially available zinc diacrylates include those from Sartomer Co. The ZDA amount can be varied to suit the desired compression, spin and feel of the resulting golf ball.
Additional preferred co-agents that may be used alone or in combination with those mentioned above include, but are not limited to, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, and the like. It is understood by those skilled in the art, that in the case where these co-agents may be liquids at room temperature, it may be advantageous to disperse these compounds on a suitable carrier to promote ease of incorporation in the rubber mixture.
Antioxidants are compounds that inhibit or prevent the oxidative breakdown of elastomers, and/or inhibit or prevent reactions that are promoted by oxygen radicals. Some exemplary antioxidants that may be used in the present invention include, but are not limited to, quinoline type antioxidants, amine type antioxidants, and phenolic type antioxidants. A preferred antioxidant is 2,2′-methylene-bis-(4-methyl-6-t-butylphenol) available as VANOX® MBPC from R.T. Vanderbilt. Other polyphenolic antioxidants include VANOX® T, VANOX® L, VANOX® SKT, VANOX® SWP, VANOX® 13 and VANOX® 1290.
Suitable antioxidants include, but are not limited to, alkylene-bis-alkyl substituted cresols, such as 4,4′-methylene-bis(2,5-xylenol); 4,4′-ethylidene-bis-(6-ethyl-m-cresol); 4,4′-butylidene-bis-(6-t-butyl-m-cresol); 4,4′-decylidene-bis-(6-methyl-m-cresol); 4,4′-methylene-bis-(2-amyl-m-cresol); 4,4′-propylidene-bis-(5-hexyl-m-cresol); 3,3′-decylidene-bis-(5-ethyl-p-cresol); 2,2′-butylidene-bis-(3-n-hexyl-p-cresol); 4,4′-(2-butylidene)-bis-(6-t-butyl-m-cresol); 3,3′-4(decylidene)-bis-(5-ethyl-p-cresol); (2,5-dimethyl-4-hydroxyphenyl)(2-hydroxy-3,5-dimethylphenyl)methane; (2-methyl-4-hydroxy-5-ethylphenyl)(2-ethyl-3-hydroxy-5-methylphenyl)methane; (3-methyl-5-hydroxy-6-t-butylphenyl)(2-hydroxy-4-methyl-5-decylphenyl)-n-butyl methane; (2-hydroxy-4-ethyl-5-methylphenyl)(2-decyl-3-hydroxy-4-methylphenyl)butylamylmethane; (3-ethyl-4-methyl-5-hydroxyphenyl)-(2,3-dimethyl-3-hydroxy-phenyl)nonylmethane; (3-methyl-2-hydroxy-6-ethylphenyl)-(2-isopropyl-3-hydroxy-5-methyl-phenyl)cyclohexylmethane; (2-methyl-4-hydroxy-5-methylphenyl)(2-hydroxy-3-methyl-5-ethylphenyl)dicyclohexyl methane; and the like.
Other suitable antioxidants include, but are not limited to, substituted phenols, such as 2-tert-butyl-4-methoxyphenol; 3-tert-butyl-4-methoxyphenol; 3-tert-octyl-4-methoxyphenol; 2-methyl-4-methoxyphenol; 2-stearyl-4-n-butoxyphenol; 3-t-butyl-4-stearyloxyphenol; 3-lauryl-4-ethoxyphenol; 2,5-di-t-butyl-4-methoxyphenol; 2-methyl-4-methoxyphenol; 2-(1-methycyclohexyl)-4-methoxyphenol; 2-t-butyl-4-dodecyloxyphenol; 2-(1-methylbenzyl)-4-methoxyphenol; 2-t-octyl-4-methoxyphenol; methyl gallate; n-propyl gallate; n-butyl gallate; lauryl gallate; myristyl gallate; stearyl gallate; 2,4,5-trihydroxyacetophenone; 2,4,5-trihydroxy-n-butyrophenone; 2,4,5-trihydroxystearophenone; 2,6-ditert-butyl-4-methylphenol; 2,6-ditert-octyl-4-methylphenol; 2,6-ditert-butyl-4-stearylphenol; 2-methyl-4-methyl-6-tert-butylphenol; 2,6-distearyl-4-methylphenol; 2,6-dilauryl-4-methylphenol; 2,6-di(n-octyl)-4-methylphenol; 2,6-di(n-hexadecyl)-4-methylphenol; 2,6-di(1-methylundecyl)-4-methylphenol; 2,6-di(1-methylheptadecyl)-4-methylphenol; 2,6-di(trimethylhexyl)-4-methylphenol; 2,6-di(1,1,3,3-tetramethyloctyl)-4-methylphenol; 2-n-dodecyl-6-tert butyl-4-methylphenol; 2-n-dodecyl-6-(1-methylundecyl)-4-methylphenol; 2-n-dodecyl-6-(1,1,3,3-tetramethyloctyl)-4-methylphenol; 2-n-dodecyl-6-n-octadecyl-4-methylphenol; 2-n-dodecyl-6-n-octyl-4-methylphenol; 2-methyl-6-n-octadecyl-4-methylphenol; 2-n-dodecyl-6-(1-methylheptadecyl)-4-methylphenol; 2,6-di(1-methylbenzyl)-4-methylphenol; 2,6-di(1-methylcyclohexyl)-4-methylphenol; 2,6-(1-methylcyclohexyl)-4-methylphenol; 2-(1-methylbenzyl)-4-methylphenol; and related substituted phenols.
More suitable antioxidants include, but are not limited to, alkylene bisphenols, such as 4,4′-butylidene bis(3-methyl-6-t-butyl phenol); 2,2-butylidene bis(4,6-dimethyl phenol); 2,2′-butylidene bis(4-methyl-6-t-butyl phenol); 2,2′-butylidene bis(4-t-butyl-6-methyl phenol); 2,2′-ethylidene bis(4-methyl-6-t-butylphenol); 2,2′-methylene bis(4,6-dimethyl phenol); 2,2′-methylene bis(4-methyl-6-t-butyl phenol); 2,2′-methylene bis(4-ethyl-6-t-butyl phenol); 4,4′-methylene bis(2,6-di-t-butyl phenol); 4,4′-methylene bis(2-methyl-6-t-butyl phenol); 4,4′-methylene bis(2,6-dimethyl phenol); 2,2′-methylene bis(4-t-butyl-6-phenyl phenol); 2,2′-dihydroxy-3,3′,5,5′-tetramethylstilbene; 2,2′-isopropylidene bis(4-methyl-6-t-butyl phenol); ethylene bis(beta-naphthol); 1,5-dihydroxy naphthalene; 2,2′-ethylene bis(4-methyl-6-propyl phenol); 4,4′-methylene bis(2-propyl-6-t-butyl phenol); 4,4′-ethylene bis(2-methyl-6-propyl phenol); 2,2′-methylene bis(5-methyl-6-t-butyl phenol); and 4,4′-butylidene bis(6-t-butyl-3-methyl phenol).
Suitable antioxidants further include, but are not limited to, alkylene trisphenols, such as 2,6-bis(2′-hydroxy-3′-t-butyl-5′-methyl benzyl)-4-methyl phenol; 2,6-bis(2′-hydroxy-3′-t-ethyl-5′-butyl benzyl)-4-methyl phenol; and 2,6-bis(2′-hydroxy-3′-t-butyl-5′-propyl benzyl)-4-methyl phenol.
The thermoset rubber composition of the present invention may also include an optional soft and fast agent. As used herein, “soft and fast agent” means any compound or a blend thereof that that is capable of making a core 1) be softer (lower compression) at constant COR or 2) have a higher COR at equal compression, or any combination thereof, when compared to a core equivalently prepared without a soft and fast agent.
Suitable soft and fast agents include, but are not limited to, organosulfur or metal-containing organosulfur compounds, an organic sulfur compound, including mono, di, and polysulfides, a thiol, or mercapto compound, an inorganic sulfide compound, a Group VIA compound, or mixtures thereof. The soft and fast agent component may also be a blend of an organosulfur compound and an inorganic sulfide compound.
Suitable soft and fast agents of the present invention include, but are not limited to those having the following general formula:
where R 1 -R 5 can be C 1 -C 8 alkyl groups; halogen groups; thiol groups (—SH), carboxylated groups; sulfonated groups; and hydrogen; in any order; and also pentafluorothiophenol; 2-fluorothiophenol; 3-fluorothiophenol; 4-fluorothiophenol; 2,3-fluorothiophenol; 2,4-fluorothiophenol; 3,4-fluorothiophenol; 3,5-fluorothiophenol 2,3,4-fluorothiophenol; 3,4,5-fluorothiophenol; 2,3,4,5-tetrafluorothiophenol; 2,3,5,6-tetrafluorothiophenol; 4-chlorotetrafluorothiophenol; pentachlorothiophenol; 2-chlorothiophenol; 3-chlorothiophenol; 4-chlorothiophenol; 2,3-chlorothiophenol; 2,4-chlorothiophenol; 3,4-chlorothiophenol; 3,5-chlorothiophenol; 2,3,4-chlorothiophenol; 3,4,5-chlorothiophenol; 2,3,4,5-tetrachlorothiophenol; 2,3,5,6-tetrachlorothiophenol; pentabromothiophenol; 2-bromothiophenol; 3-bromothiophenol; 4-bromothiophenol; 2,3-bromothiophenol; 2,4-bromothiophenol; 3,4-bromothiophenol; 3,5-bromothiophenol; 2,3,4-bromothiophenol; 3,4,5-bromothiophenol; 2,3,4,5-tetrabromothiophenol; 2,3,5,6-tetrabromothiophenol; pentaiodothiophenol; 2-iodothiophenol; 3-iodothiophenol; 4-iodothiophenol; 2,3-iodothiophenol; 2,4-iodothiophenol; 3,4-iodothiophenol; 3,5-iodothiophenol; 2,3,4-iodothiophenol; 3,4,5-iodothiophenol; 2,3,4,5-tetraiodothiophenol; 2,3,5,6-tetraiodothiophenol and; and their zinc salts. Preferably, the halogenated thiophenol compound is pentachlorothiophenol, which is commercially available in neat form or under the tradename STRUKTOL®, a clay-based carrier containing the sulfur compound pentachlorothiophenol loaded at 45 percent (correlating to 2.4 parts PCTP). STRUKTOL® is commercially available from Struktol Company of America of Stow, Ohio. PCTP is commercially available in neat form from eChinachem of San Francisco, Calif. and in the salt form from eChinachem of San Francisco, Calif. Most preferably, the halogenated thiophenol compound is the zinc salt of pentachlorothiophenol, which is commercially available from eChinachem of San Francisco, Calif.
As used herein when referring to the invention, the term “organosulfur compound(s)” refers to any compound containing carbon, hydrogen, and sulfur, where the sulfur is directly bonded to at least 1 carbon. As used herein, the term “sulfur compound” means a compound that is elemental sulfur, polymeric sulfur, or a combination thereof. It should be further understood that the term “elemental sulfur” refers to the ring structure of S 8 and that “polymeric sulfur” is a structure including at least one additional sulfur relative to elemental sulfur.
Additional suitable examples of soft and fast agents (that are also believed to be cis-to-trans catalysts) include, but are not limited to, 4,4′-diphenyl disulfide; 4,4′-ditolyl disulfide; 2,2′-benzamido diphenyl disulfide; bis(2-aminophenyl)disulfide; bis(4-aminophenyl)disulfide; bis(3-aminophenyl)disulfide; 2,2′-bis(4-aminonaphthyl)disulfide; 2,2′-bis(3-aminonaphthyl)disulfide; 2,2′-bis(4-aminonaphthyl)disulfide; 2,2′-bis(5-aminonaphthyl)disulfide; 2,2′-bis(6-aminonaphthyl)disulfide; 2,2′-bis(7-aminonaphthyl)disulfide; 2,2′-bis(8-aminonaphthyl) disulfide; 1,1′-bis(2-aminonaphthyl)disulfide; 1,1′-bis(3-aminonaphthyl)disulfide; 1,1′-bis(3-aminonaphthyl)disulfide; 1,1′-bis(4-aminonaphthyl)disulfide; 1,1′-bis(5-aminonaphthyl) disulfide; 1,1′-bis(6-aminonaphthyl)disulfide; 1,1′-bis(7-aminonaphthyl)disulfide; 1,1′-bis(8-aminonaphthyl)disulfide; 1,2′-diamino-1,2′-dithiodinaphthalene; 2,3′-diamino-1,2′-dithiodinaphthalene; bis(4-chlorophenyl)disulfide; bis(2-chlorophenyl)disulfide; bis(3-chlorophenyl)disulfide; bis(4-bromophenyl)disulfide; bis(2-bromophenyl)disulfide; bis(3-bromophenyl)disulfide; bis(4-fluorophenyl)disulfide; bis(4-iodophenyl)disulfide; bis(2,5-dichlorophenyl)disulfide; bis(3,5-dichlorophenyl)disulfide; bis(2,4-dichlorophenyl)disulfide; bis(2,6-dichlorophenyl)disulfide; bis(2,5-dibromophenyl)disulfide; bis(3,5-dibromophenyl)disulfide; bis(2-chloro-5-bromophenyl)disulfide; bis(2,4,6-trichlorophenyl)disulfide; bis(2,3,4,5,6-pentachlorophenyl)disulfide; bis(4-cyanophenyl)disulfide; bis(2-cyanophenyl)disulfide; bis(4-nitrophenyl)disulfide; bis(2-nitrophenyl)disulfide; 2,2′-dithiobenzoic acid ethylester; 2,2′-dithiobenzoic acid methylester; 2,2′-dithiobenzoic acid; 4,4′-dithiobenzoic acid ethylester; bis(4-acetylphenyl)disulfide; bis(2-acetylphenyl)disulfide; bis(4-formylphenyl)disulfide; bis(4-carbamoylphenyl)disulfide; 1,1′-dinaphthyl disulfide; 2,2′-dinaphthyl disulfide; 1,2′-dinaphthyl disulfide; 2,2′-bis(1-chlorodinaphthyl)disulfide; 2,2′-bis(1-bromonaphthyl) disulfide; 1,1′-bis(2-chloronaphthyl)disulfide; 2,2′-bis(1-cyanonaphthyl)disulfide; 2,2′-bis(1-acetylnaphthyl)disulfide; and the like; or a mixture thereof. Preferred organosulfur components include 4,4′-diphenyl disulfide, 4,4′-ditolyl disulfide, or 2,2′-benzamido diphenyl disulfide, or a mixture thereof. A more preferred organosulfur component includes 4,4′-ditolyl disulfide. In another embodiment, metal-containing organosulfur components can be used according to the invention. Suitable metal-containing organosulfur components include, but are not limited to, cadmium, copper, lead, and tellurium analogs of diethyldithiocarbamate, diamyldithiocarbamate, and dimethyldithiocarbamate, or mixtures thereof.
Suitable substituted or unsubstituted aromatic organic components that do not include sulfur or a metal include, but are not limited to, 4,4′-diphenyl acetylene, azobenzene, or a mixture thereof. The aromatic organic group preferably ranges in size from C 6 to C 20 , and more preferably from C 6 to C 10 . Suitable inorganic sulfide components include, but are not limited to titanium sulfide, manganese sulfide, and sulfide analogs of iron, calcium, cobalt, molybdenum, tungsten, copper, selenium, yttrium, zinc, tin, and bismuth.
A substituted or unsubstituted aromatic organic compound is also suitable as a soft and fast agent. Suitable substituted or unsubstituted aromatic organic components include, but are not limited to, components having the formula (R 1 ) x —R 3 -M-R 4 —(R 2 ) y , wherein R 1 and R 2 are each hydrogen or a substituted or unsubstituted C 1-20 linear, branched, or cyclic alkyl, alkoxy, or alkylthio group, or a single, multiple, or fused ring C 6 to C 24 aromatic group; x and y are each an integer from 0 to 5; R 3 and R 4 are each selected from a single, multiple, or fused ring C 6 to C 24 aromatic group; and M includes an azo group or a metal component. R 3 and R 4 are each preferably selected from a C 6 to C 10 aromatic group, more preferably selected from phenyl, benzyl, naphthyl, benzamido, and benzothiazyl. R 1 and R 2 are each preferably selected from a substituted or unsubstituted C 1-10 linear, branched, or cyclic alkyl, alkoxy, or alkylthio group or a C 6 to C 10 aromatic group. When R 1 , R 2 , R 3 , or R 4 , are substituted, the substitution may include one or more of the following substituent groups: hydroxy and metal salts thereof; mercapto and metal salts thereof; halogen; amino, nitro, cyano, and amido; carboxyl including esters, acids, and metal salts thereof; silyl; acrylates and metal salts thereof; sulfonyl or sulfonamide; and phosphates and phosphites. When M is a metal component, it may be any suitable elemental metal available to those of ordinary skill in the art. Typically, the metal will be a transition metal, although preferably it is tellurium or selenium. In one embodiment, the aromatic organic compound is substantially free of metal, while in another embodiment the aromatic organic compound is completely free of metal.
The soft and fast agent can also include a Group VIA component. Elemental sulfur and polymeric sulfur are commercially available from Elastochem, Inc. of Chardon, Ohio. Exemplary sulfur catalyst compounds include PB(RM-S)-80 elemental sulfur and PB(CRST)-65 polymeric sulfur, each of which is available from Elastochem, Inc. An exemplary tellurium catalyst under the tradename TELLOY® and an exemplary selenium catalyst under the tradename VANDEX® are each commercially available from RT Vanderbilt.
Other suitable soft and fast agents include, but are not limited to, hydroquinones, benzoquinones, quinhydrones, catechols, and resorcinols.
Suitable hydroquinone compounds include compounds represented by the following formula, and hydrates thereof:
wherein each R 1 , R 2 , R 3 , and R 4 are hydrogen; halogen; alkyl; carboxyl; metal salts thereof, and esters thereof; acetate and esters thereof; formyl; acyl; acetyl; halogenated carbonyl; sulfo and esters thereof; halogenated sulfonyl; sulfino; alkylsulfinyl; carbamoyl; halogenated alkyl; cyano; alkoxy; hydroxy and metal salts thereof; amino; nitro; aryl; aryloxy; arylalkyl; nitroso; acetamido; or vinyl.
Other suitable hydroquinone compounds include, but are not limited to, hydroquionone; tetrachlorohydroquinone; 2-chlorohydroquionone; 2-bromohydroquinone; 2,5-dichlorohydroquinone; 2,5-dibromohydroquinone; tetrabromohydroquinone; 2-methylhydroquinone; 2-t-butylhydroquinone; 2,5-di-t-amylhydroquinone; and 2-(2-chlorophenyl)hydroquinone hydrate.
More suitable hydroquinone compounds include compounds represented by the following formula, and hydrates thereof:
wherein each R 1 , R 2 , R 3 , and R 4 are a metal salt of a carboxyl; acetate and esters thereof; hydroxy; a metal salt of a hydroxy; amino; nitro; aryl; aryloxy; arylalkyl; nitroso; acetamido; or vinyl.
Suitable benzoquinone compounds include compounds represented by the following formula, and hydrates thereof:
wherein each R 1 , R 2 , R 3 , and R 4 are hydrogen; halogen; alkyl; carboxyl; metal salts thereof, and esters thereof; acetate and esters thereof; formyl; acyl; acetyl; halogenated carbonyl; sulfo and esters thereof; halogenated sulfonyl; sulfino; alkylsulfinyl; carbamoyl; halogenated alkyl; cyano; alkoxy; hydroxy and metal salts thereof; amino; nitro; aryl; aryloxy; arylalkyl; nitroso; acetamido; or vinyl.
Other suitable benzoquinone compounds include one or more compounds represented by the following formula, and hydrates thereof:
wherein each R 1 , R 2 , R 3 , and R 4 are a metal salt of a carboxyl; acetate and esters thereof; hydroxy; a metal salt of a hydroxy; amino; nitro; aryl; aryloxy; arylalkyl; nitroso; acetamido; or vinyl.
Suitable quinhydrones include one or more compounds represented by the following formula, and hydrates thereof:
wherein each R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , and R 8 are hydrogen; halogen; alkyl; carboxyl; metal salts thereof, and esters thereof; acetate and esters thereof; formyl; acyl; acetyl; halogenated carbonyl; sulfo and esters thereof; halogenated sulfonyl; sulfino; alkylsulfinyl; carbamoyl; halogenated alkyl; cyano; alkoxy; hydroxy and metal salts thereof; amino; nitro; aryl; aryloxy; arylalkyl; nitroso; acetamido; or vinyl.
Other suitable quinhydrones include those having the above formula, wherein each R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , and R 8 are a metal salt of a carboxyl; acetate and esters thereof; hydroxy; a metal salt of a hydroxy; amino; nitro; aryl; aryloxy; arylalkyl; nitroso; acetamido; or vinyl.
Suitable catechols include one or more compounds represented by the following formula, and hydrates thereof:
wherein each R 1 , R 2 , R 3 , and R 4 are hydrogen; halogen; alkyl; carboxyl; metal salts thereof, and esters thereof; acetate and esters thereof; formyl; acyl; acetyl; halogenated carbonyl; sulfo and esters thereof; halogenated sulfonyl; sulfino; alkylsulfinyl; carbamoyl; halogenated alkyl; cyano; alkoxy; hydroxy and metal salts thereof; amino; nitro; aryl; aryloxy; arylalkyl; nitroso; acetamido; or vinyl.
Suitable resorcinols include one or more compounds represented by the following formula, and hydrates thereof:
wherein each R 1 , R 2 , R 3 , and R 4 are hydrogen; halogen; alkyl; carboxyl; metal salts thereof, and esters thereof; acetate and esters thereof; formyl; acyl; acetyl; halogenated carbonyl; sulfo and esters thereof; halogenated sulfonyl; sulfino; alkylsulfinyl; carbamoyl; halogenated alkyl; cyano; alkoxy; hydroxy and metal salts thereof; amino; nitro; aryl; aryloxy; arylalkyl; nitroso; acetamido; or vinyl.
Fillers may also be added to the thermoset rubber composition of the core to adjust the density of the composition, up or down. Typically, fillers include materials such as tungsten, zinc oxide, barium sulfate, silica, calcium carbonate, zinc carbonate, metals, metal oxides and salts, regrind (recycled core material typically ground to about 30 mesh particle), high-Mooney-viscosity rubber regrind, trans-regrind core material (recycled core material containing high trans-isomer of polybutadiene), and the like. When trans-regrind is present, the amount of trans-isomer is preferably between about 10% and about 60%. In a preferred embodiment of the invention, the core comprises polybutadiene having a cis-isomer content of greater than about 95% and trans-regrind core material (already vulcanized) as a filler. Any particle size trans-regrind core material is sufficient, but is preferably less than about 125 μm.
Fillers added to one or more portions of the golf ball typically include processing aids or compounds to affect rheological and mixing properties, density-modifying fillers, tear strength, or reinforcement fillers, and the like. The fillers are generally inorganic, and suitable fillers include numerous metals or metal oxides, such as zinc oxide and tin oxide, as well as barium sulfate, zinc sulfate, calcium carbonate, barium carbonate, clay, tungsten, tungsten carbide, an array of silicas, and mixtures thereof. Fillers may also include various foaming agents or blowing agents which may be readily selected by one of ordinary skill in the art. Fillers may include polymeric, ceramic, metal, and glass microspheres may be solid or hollow, and filled or unfilled. Fillers are typically also added to one or more portions of the golf ball to modify the density thereof to conform to uniform golf ball standards. Fillers may also be used to modify the weight of the center or at least one additional layer for specialty balls, e.g., a lower weight ball is preferred for a player having a low swing speed.
Materials such as tungsten, zinc oxide, barium sulfate, silica, calcium carbonate, zinc carbonate, metals, metal oxides and salts, and regrind (recycled core material typically ground to about 30 mesh particle) are also suitable fillers.
The polybutadiene and/or any other base rubber or elastomer system may also be foamed, or filled with hollow microspheres or with expandable microspheres which expand at a set temperature during the curing process to any low specific gravity level. Other ingredients such as sulfur accelerators, e.g., tetra methylthiuram di, tri, or tetrasulfide, and/or metal-containing organosulfur components may also be used according to the invention. Suitable metal-containing organosulfur accelerators include, but are not limited to, cadmium, copper, lead, and tellurium analogs of diethyldithiocarbamate, diamyldithiocarbamate, and dimethyldithiocarbamate, or mixtures thereof. Other ingredients such as processing aids e.g., fatty acids and/or their metal salts, processing oils, dyes and pigments, as well as other additives known to one skilled in the art may also be used in the present invention in amounts sufficient to achieve the purpose for which they are typically used.
The ratio of antioxidant to initiator and the cure cycle temperatures and durations are some factors which control the surface hardness of each core layer and provide the inventive regions of varying hardness within each core layer.
Referring to FIG. 1 , golf ball 10 in accordance with the present invention is constructed to provide the desired spin profile and playing characteristics. In an embodiment as illustrated, golf ball 10 includes core 16 having core layers 17 and 18 and cover layer 15 surrounding core 16 . In one embodiment, the diameter of core 16 is greater than about 1.58 inches. Preferably, the diameter of core 16 is greater than about 1.6 inches. Core layers 17 and 18 represent the inner core layer and outer core layer, respectively, as disclosed and claimed herein.
Examples of suitable formulations for several embodiments of golf ball 10 as discussed in SECTION I are summarized in the following TABLE I:
TABLE I
Ranges
Ranges
Components
Inner Core
Outer Core
(phr)
A
B
C
D
ZDA
25-35
30-40
25-40
25-40
ZnO
5-10
5-10
5-10
5-10
BaSO 4
Vary to achieve targeted specific gravity
VANOX MBPC*
0-1.0
0-1.0
0.2-1.2
0
(Antioxidant)
TRIGONOX**
0.5-1.0
0.5-1.2
0.5-1.2
0
PERKADOX
—
—
0
0.5-1.5
BC-FF***
Polybutadiene
100
100
85-100
85-100
Trans polyisoprene
0-15
0-15
0-15
0-15
ZnPCTP
0-3
0-3
0-3
0-3
Regrind
10-30
10-30
10-30
10-30
antioxidant/
0-2.5
0-4.8
0.33-4.8
—
initiator ratio
Cure Temp. (° F.)
325-350
290-315
100-150
100-150
Cure Time T 1 (min)
10-15
15-20
3-7
3-7
Cure Temp. (° F.)
—
—
290-315
330-350
Cure Time T 2 (min)
—
—
5-10
5-10
Layer Diameter/
0.75-1.25
0.75-1.25
0.14-0.415
0.14-0.415
Thickness (in)
Atti compression
—
—
75-100
75-100
COR @ 125 ft/s
—
—
0.795
0.795
The invention cores of the invention may also additional materials as disclosed herein.
FIGS. 2 and 3 illustrate several golf balls according to the invention. The inner core layer may have a hardness gradient represented by slope A, while the outer core layer meanwhile having a hardness gradient represented by either curve C or curve D. Alternatively, the inner core layer may a hardness gradient represented by slope B, the outer core layer meanwhile having a hardness gradient represented by either curve C or curve D. In each of these cases, the first hardness is located at the geometric center (0 mm from the center), the second and third hardnesses are located on the first outer surface and inner surface, respectively, about the vertical dotted line 10 mm to 15 mm from the geometric center. In FIGS. 2 and 3 , the second and third hardnesses are different from each other. However, the second and third hardnesses may alternatively be substantially similar to each other. The fourth hardness is located about 20 mm from the geometric center in FIGS. 2 and 3 . The fifth hardness appears between the third and fourth hardnesses in a region extending between about 10% and about 90% of the distance from the inner surface to the second outer surface. As discussed more fully throughout, each embodiment defines particular examples of possible hardness relationships between the first, second third, fourth and fifth hardnesses.
Examples of suitable formulations for several embodiments of golf ball 10 as discussed in SECTION II are summarized in the following TABLE II:
TABLE II
Ranges
Component
Ranges
Outer Core
(phr)
Inner Core
A
B
ZDA
35-45
39-45
35-42
ZnO
5-10
5-10
5-10
BaSO 4
Vary to achieve targeted specific gravity
VANOX
0
0.2-1.0
0.2-1.0
MBPC*
(Antioxidant)
TRIGONOX
0
0.8-1.5
0.6-1.2
265**
PERKADOX
0.6-1.2
—
—
BC-FF***
Polybutadiene
100
85-100
85-100
Trans
0-15
0-15
0-15
polyisoprene
ZnPCTP
0-3
0-3
0-3
Regrind
10-30
10-30
10-30
antioxidant/
—
0.27-2.5
0.33-3.33
initiator ratio
Cure Temp.
340° F.-365° F.
100° F.-150° F.
100° F.-150° F.
(° F.)
Cure Time T 1
10-15
2-7
2-7
(min)
Cure Temp.
—
320° F.-330° F.
300° F.-320° F.
(° F.)
Cure Time T 2
—
10-15
15-20
(min)
Layer
0.75-1.25
0.14-0.415
0.14-0.415
Diameter/
Thickness (in)
Atti
—
80-100
90-120
compression
COR @ 125
—
0.795-0.820
0.800-0.825
ft/s
The inventive cores of the invention may also include additional materials as disclosed herein.
FIGS. 4 and 5 illustrate several golf balls according to the invention. The inner core layer may have a hardness gradient represented by slope A, the outer core layer meanwhile having a hardness gradient represented by either curve B or curve C. In each of these cases, the first hardness is located at the geometric center (0 mm from the center), the second and third hardnesses are located on the first outer surface and inner surface, respectively, about the vertical dotted line 10 mm to 15 mm from the geometric center. In FIGS. 4 and 5 , the second and third hardnesses are similar. The fourth hardness is located about 20 mm from the geometric center, and the fifth hardness appears between the third and fourth hardnesses in a region extending between about 10% and about 90% of the distance from the inner surface to the second outer surface. As discussed more fully throughout, each embodiment defines particular examples of possible hardness relationships between the first, second third, fourth and fifth hardnesses.
Examples of suitable formulations for several embodiments of golf ball 10 as discussed in SECTION III are summarized in the following table:
TABLE III
Ranges
Component
Ranges
Outer Core
(phr)
Inner Core
A
B
ZDA
35-45
39-45
35-42
ZnO
5-10
5-10
5-10
BaSO 4
Vary to achieve targeted specific gravity
VANOX MBPC*
0-1.0
0.2-1.0
0.2-1.0
(Antioxidant)
TRIGONOX**
0.5-1.0
0.8-1.5
0.6-1.2
Polybutadiene
100
85-100
85-100
Trans polyisoprene
0-15
0-15
0-15
ZnPCTP
0-3
0-3
0-3
Regrind
10-30
10-30
10-30
antioxidant/initiator
0-2.5
0.27-2.5
0.33-3.33
ratio
Cure Temp. (° F.)
325-250
100° F.-150° F.
100° F.-150° F.
Cure Time T 1 (min)
10-15
2-7
2-7
Cure Temp. (° F.)
—
320° F.-330° F.
300° F.-320° F.
Cure Time T 2 (min)
—
10-15
15-20
Layer Diameter/
0.75-1.25
0.14-0.415
0.14-0.415
Thickness (in)
Atti compression
—
80-100
90-120
COR @ 125 ft/s
—
0.795-0.820
0.800-0.825
The inventive cores of the invention may also include additional materials as disclosed herein.
FIGS. 6 and 7 illustrate several golf balls according to the invention. The inner core layer may have a hardness gradient represented by slope A, the outer core layer meanwhile having a hardness gradient represented by either curve B or curve C. In each of these cases, the first hardness is located at the geometric center (0 mm from the center), the second and third hardnesses are located on the first outer surface and inner surface, respectively, about the vertical dotted line 10 mm to 15 mm from the geometric center. In FIGS. 6 and 7 , the second and third hardnesses are similar. The fourth hardness is located about 20 mm from the geometric center, and the fifth hardness appears between the third and fourth hardnesses in a region extending between about 10% and about 90% of the distance from the inner surface to the second outer surface. As discussed more fully throughout, each embodiment defines particular examples of possible hardness relationships between the first, second third, fourth and fifth hardnesses.
Examples of suitable formulations for several embodiments of golf ball 10 as discussed in SECTION IV are summarized in the following TABLE IV:
TABLE IV
Ranges
Components
Ranges
Outer Core
(phr)
Inner Core
A
B
C
ZDA
40-50
30-45
30-45
30-45
ZnO
5-10
5-10
5-10
5-10
BaSO 4
Vary to achieve targeted specific gravity
VANOX MBPC*
0.2-1.2
0
0-1.0
0.2-1.2
(Antioxidant)
TRIGONOX**
0.5-1.2
0
0.2-0.8
0.5-1.2
PERKADOX BC-FF***
—
0.5-1.0
0-1.0
0
Polybutadiene
100
100
100
100
Trans polyisoprene
0-15
0-15
0-15
0-15
ZnPCTP
0-3
0-3
0-3
0-3
Regrind
10-30
10-30
10-30
10-30
antioxidant/initiator ratio
0.33-4.8
0
0-10
0.33-4.8
Cure Temp. (° F.)
290° F.-315° F.
100° F.-150° F.
100° F.-150° F.
100° F.-150° F.
Cure Time T 1 (min)
15-25
1-3
1-3
1-3
Cure Temp. (° F.)
290° F.-315° F.
335° F.-365° F.
335° F.-365° F.
335° F.-365° F.
Cure Time T 2 (min)
—
9-14
9-14
9-14
Layer Diameter/Thickness(in)
0.75-1.25
0.14-0.415
0.14-0.415
0.14-0.415
Atti compression
—
75-100
75-100
75-100
COR @ 125 ft/s
—
0.795-0.825
0.795-0.825
0.795-0.825
The inventive cores of the invention may also include additional materials as disclosed herein.
FIGS. 8 and 9 illustrate several golf balls according to the invention. The inner core layer may have a hardness gradient represented by slope A, the outer core layer meanwhile having a hardness gradient represented by either of curves B, C or D. In each of these cases, the first hardness is located at the geometric center (0 mm from the center), the second and third hardnesses are located on the first outer surface and inner surface, respectively, about the vertical dotted line 10 mm to 15 mm from the geometric center. In FIGS. 8 and 9 , the second and third hardnesses are similar. The fourth hardness is located about 20 mm from the geometric center, and the fifth hardness appears between the third and fourth hardnesses in a region extending between about 10% and about 90% of the distance from the inner surface to the second outer surface. As discussed more fully throughout, each embodiment defines particular examples of possible hardness relationships between the first, second third, fourth and fifth hardnesses.
Examples of suitable formulations for several embodiments of golf ball 10 as discussed in SECTION V are summarized in the following TABLES V and VI:
TABLE V
Ranges
Ranges
Outer Core
Components (phr)
Inner Core
A
B
C
ZDA
25-35
30-45
30-45
30-45
ZnO
5-10
5-10
5-10
5-10
BaSO 4
Vary to achieve targeted specific gravity
VANOX MBPC
0.2-1.2
0
0-1.0
0.2-1.2
(Antioxidant)
TRIGONOX 265
0.5-1.2
0
0.2-0.8
0.5-1.2
PERKADOX BC-FF
—
0.5-1.0
0-1.0
0
Polybutadiene
100
85-100
85-100
85-100
Trans polyisoprene
0-15
0-15
0-15
0-15
ZnPCTP
0-3
0-3
0-3
0-3
Regrind
10-30
10-30
10-30
10-30
antioxidant/initiator ratio
0.33-4.8
0
0-10
0.33-4.8
Cure Temp. (° F.)
285° F.-310° F.
100° F.-150° F.
100° F.-150° F.
100° F.-150° F.
Cure Time T 1 (min)
15-20
1-3
1-3
1-3
Cure Temp. (° F.)
285° F.-310° F.
335° F.-365° F.
335° F.-365° F.
335° F.-365° F.
Cure Time T 2 (min)
—
9-14
9-14
9-14
Layer Diameter/Thickness(in)
0.25-1.25
0.14-0.415
0.14-0.415
0.14-0.415
Atti compression
—
75-100
75-100
75-100
COR @ 125 ft/s
—
0.795-0.825
0.795-0.825
0.795-0.825
TABLE VI
Ranges
Ranges Outer Core
Components (phr)
Inner Core
D
E
ZDA
25-35
25-35
25-35
ZnO
5-10
5-10
5-10
BaSO 4
Vary to achieve targeted specific gravity
VANOX MBPC
0.2-1.2
0-0.5
0-1.0
(Antioxidant)
TRIGONOX 265
0.5-1.2
0
0
PERKADOX BC-FF
—
0.5-1.5
0.5-1.5
Polybutadiene
100
100
100
Trans polyisoprene
0-15
0-15
0-15
ZnPCTP
0-3
0-3
0-3
Regrind
10-30
10-30
10-30
antioxidant/initiator ratio
0.33-4.8
0-1.0
0-2.0
Cure Temp. (° F.)
285° F.-310° F.
330-360
330-360
Cure Time T 1 (min)
15-20
8-15
8-15
Layer Diameter/Thickness(in)
0.25-1.25
The inventive cores of the invention may also include additional materials as disclosed herein.
FIGS. 10A, 10B and 11A, 11B illustrate several golf balls according to the invention. The inner core layer may have a hardness gradient represented by slope A, the outer core layer meanwhile having a hardness gradient represented by either of curves B, C, D, E or F. In each of these cases, the first hardness is located at the geometric center (0 mm from the center), the second and third hardnesses are located on the first outer surface and inner surface, respectively, about the vertical dotted line 10 mm to 15 mm from the geometric center. In FIGS. 10A, 10B and 11A, 11B , the second and third hardnesses are similar. The fourth hardness is located about 20 mm from the geometric center, and the fifth hardness appears between the third and fourth hardnesses in a region extending between about 10% and about 90% of the distance from the inner surface to the second outer surface. As discussed more fully throughout, each embodiment defines particular examples of possible hardness relationships between the first, second third, fourth and fifth hardnesses.
The surface hardness of a core is obtained from the average of a number of measurements taken from opposing hemispheres of a core, taking care to avoid making measurements on the parting line of the core or on surface defects, such as holes or protrusions. Hardness measurements are made pursuant to ASTM D-2240 “Indentation Hardness of Rubber and Plastic by Means of a Durometer.” Because of the curved surface of a core, care must be taken to insure that the core is centered under the durometer indentor before a surface hardness reading is obtained. A calibrated, digital durometer, capable of reading to 0.1 hardness units is used for all hardness measurements and is set to take the peak hardness reading. The digital durometer must be attached to, and its foot made parallel to, the base of an automatic stand, such that the weight on the durometer and attack rate conform to ASTM D-2240.
To prepare a core for hardness gradient measurements, the core is gently pressed into a hemispherical holder having an internal diameter approximately slightly smaller than the diameter of the core, such that the core is held in place in the hemispherical portion of the holder while concurrently leaving the geometric central plane of the core exposed. The core is secured in the holder by friction, such that it will not move during the cutting and grinding steps, but the friction is not so excessive that distortion of the natural shape of the core would result. The core is secured such that the parting line of the core is roughly parallel to the top of the holder. The diameter of the core is measured 90 degrees to this orientation prior to securing. A measurement is also made from the bottom of the holder to the top of the core to provide a reference point for future calculations. A rough cut, made slightly above the exposed geometric center of the core using a band saw or other appropriate cutting tool, making sure that the core does not move in the holder during this step. The remainder of the core, still in the holder, is secured to the base plate of a surface grinding machine. The exposed ‘rough’ core surface is ground to a smooth, flat surface, revealing the geometric center of the core, which can be verified by measuring the height of the bottom of the holder to the exposed surface of the core, making sure that exactly half of the original height of the core, as measured above, has been removed to within ±0.004 inches.
Leaving the core in the holder, the center of the core is found with a center square and carefully marked and the hardness is measured at the center mark. Hardness measurements at any distance from the center of the core may be measured by drawing a line radially outward from the center mark, and measuring and marking the distance from the center, typically in 2-mm increments. All hardness measurements performed on the plane passing through the geometric center are performed while the core is still in the holder and without having disturbed its orientation, such that the test surface is constantly parallel to the bottom of the holder. The hardness difference from any predetermined location on the core (e.g., first outer surface, second outer surface, etc.) is calculated as the average hardness at the predetermined location minus the hardness at a chosen reference point at or closer to the geometric center than the predetermined location. For example, if the predetermined location is the second outer surface and is softer than its reference point, the inner surface, a negative hardness gradient results between the two points. Conversely, if inner surface is harder than the second outer surface, a positive hardness gradient results.
Golf ball compression remains an important factor to consider in maximizing playing performance. It affects the ball's spin rate off the driver as well as the feel. Initially, compression was referred to as the tightness of the windings around a golf ball. Today, compression refers to how much a ball will deform under a compressive force when a driver hits the ball. A ball actually tends to flatten out when a driver meets the ball; it deforms out of its round shape and then returns to its round shape, all in a second or two. Compression ratings of from about 70 to about 120 are common. The lower the compression rating, the more the ball will compress or deform upon impact.
People with a slower swing or slower club head speed will desire a ball having a lower compression rating. While the compression of a ball alone does not determine whether a ball flies farther—the club head speed actually determines that—compression can nevertheless influence or contribute to overall distance. For example, a golfer with a slower club head speed who uses a high compression ball will indeed lose yardage that would otherwise be achieved if that golfer used a low compression (or softer) ball. Accordingly, it is desirable to match golf ball compression rating with a player's swing speed in maximizing a golfer's performance on the green.
Several different methods can be used to measure compression, including Atti compression, Riehle compression, load/deflection measurements at a variety of fixed loads and offsets, and effective modulus. See, e.g., Compression by Any Other Name, Science and Golf IV, Proceedings of the World Scientific Congress of Golf (Eric Thain ed., routledge, 2002) (“ J. Dalton ”) The term compression, as used herein, refers to Atti compression and is measured using an Atti compression test device. A piston compresses a ball against a spring and the piston remains fixed while deflection of the spring is measured at 1.25 mm (0.05 inches). Where a core has a very low stiffness, the compression measurement will be zero at 1.25 mm. In order to measure the compression of a core using an Atti compression tester, the core must be shimmed to a diameter of 1.680 inches because these testers are designed to measure objects having that diameter. Atti compression units can be converted to Riehle (cores), Riehle (balls), 100 kg deflection, 130-10 kg deflection or effective modulus using the formulas set forth in J. Dalton.
According to one aspect of the present invention, the golf ball is formulated to have a compression of between about 50 and about 120. In one embodiment, the compression of core 16 is greater than about 50. In another embodiment, the compression of core 16 is greater than about 70. In yet another embodiment, the compression of core 16 is from about 80 to about 100.
The distance that a golf ball would travel upon impact is a function of the coefficient of restitution (COR) and the aerodynamic characteristics of the ball. For golf balls, COR has been approximated as a ratio of the velocity of the golf ball after impact to the velocity of the golf ball prior to impact. The COR varies from 0 to 1.0. A COR value of 1.0 is equivalent to a perfectly elastic collision, that is, all the energy is transferred in the collision. A COR value of 0.0 is equivalent to a perfectly inelastic collision—that is, all of the energy is lost in the collision.
COR, as used herein, is determined by firing a golf ball or golf ball subassembly (e.g., a golf ball core) from an air cannon at two given velocities and calculating the COR at a velocity of 125 ft/s. Ball velocity is calculated as a ball approaches ballistic light screens which are located between the air cannon and a steel plate at a fixed distance. As the ball travels toward the steel plate, each light screen is activated, and the time at each light screen is measured. This provides an incoming transit time period inversely proportional to the ball's incoming velocity. The ball impacts the steel plate and rebounds through the light screens, which again measure the time period required to transit between the light screens. This provides an outgoing transit time period inversely proportional to the ball's outgoing velocity. COR is then calculated as the ratio of the outgoing transit time period to the incoming transit time period, COR=V out /V in =T in /T out . Preferably, a golf ball according to the present invention has a COR of at least about 0.78, more preferably, at least about 0.80.
The spin rate of a golf ball also remains an important golf ball characteristic. High spin rate allows skilled players more flexibility in stopping the ball on the green if they are able to control a high spin ball. On the other hand, recreational players often prefer a low spin ball since they do not have the ability to intentionally control the ball, and lower spin balls tend to drift less off the green.
Golf ball spin is dependent on variables including, for example, distribution of the density or specific gravity within a golf ball. For example, when the density or specific gravity is located in the golf ball center, a lower moment of inertia results which increases spin rate. Alternatively, when the density or specific gravity is concentrated in the outer regions of the golf ball, a higher moment of inertia results with a lower spin rate. The moment of inertia for a one piece ball that is 1.62 ounces and 1.68 inches in diameter is approximately 0.4572 oz-in 2 , which is the baseline moment of inertia value.
Accordingly, by varying the materials and the hardness of the regions of each core layer, different moments of inertia may be achieved for the golf ball of the present invention. In one embodiment, the resulting golf ball has a moment of inertia of from about to 0.440 to about 0.455 oz-in 2 . In another embodiment, the golf balls of the present invention have a moment of inertia of from about 0.456 oz-in 2 to about 0.470 oz-in 2 . In yet another embodiment, the golf ball has a moment of inertia of from about 0.450 oz-in 2 to about 0.460 oz-in 2 .
While the inventive golf ball may be formed from a variety of differing and conventional cover materials (both intermediate layer(s) and outer cover layer), preferred cover materials include, but are not limited to:
(1) Polyurethanes, such as those prepared from polyols or polyamines and diisocyanates or polyisocyanates and/or their prepolymers, and those disclosed in U.S. Pat. Nos. 5,334,673 and 6,506,851;
(2) Polyureas, such as those disclosed in U.S. Pat. Nos. 5,484,870 and 6,835,794; and (3) Polyurethane-urea hybrids, blends or copolymers comprising urethane or urea segments.
Suitable polyurethane compositions comprise a reaction product of at least one polyisocyanate and at least one curing agent. The curing agent can include, for example, one or more polyamines, one or more polyols, or a combination thereof. The polyisocyanate can be combined with one or more polyols to form a prepolymer, which is then combined with the at least one curing agent. Thus, the polyols described herein are suitable for use in one or both components of the polyurethane material, i.e., as part of a prepolymer and in the curing agent. Suitable polyurethanes are described in U.S. Patent Application Publication No. 2005/0176523, which is incorporated by reference in its entirety.
Any polyisocyanate available to one of ordinary skill in the art is suitable for use according to the invention. Exemplary polyisocyanates include, but are not limited to, 4,4′-diphenylmethane diisocyanate (MDI); polymeric MDI; carbodiimide-modified liquid MDI; 4,4′-dicyclohexylmethane diisocyanate (H 12 MDI); p-phenylene diisocyanate (PPDI); m-phenylene diisocyanate (MPDI); toluene diisocyanate (TDI); 3,3′-dimethyl-4,4′-biphenylene diisocyanate; isophoronediisocyanate; 1,6-hexamethylene diisocyanate (HDI); naphthalene diisocyanate; xylene diisocyanate; p-tetramethylxylene diisocyanate; m-tetramethylxylene diisocyanate; ethylene diisocyanate; propylene-1,2-diisocyanate; tetramethylene-1,4-diisocyanate; cyclohexyl diisocyanate; dodecane-1,12-diisocyanate; cyclobutane-1,3-diisocyanate; cyclohexane-1,3-diisocyanate; cyclohexane-1,4-diisocyanate; 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane; methyl cyclohexylene diisocyanate; triisocyanate of HDI; triisocyanate of 2,4,4-trimethyl-1,6-hexane diisocyanate; tetracene diisocyanate; napthalene diisocyanate; anthracene diisocyanate; isocyanurate of toluene diisocyanate; uretdione of hexamethylene diisocyanate; and mixtures thereof. Polyisocyanates are known to those of ordinary skill in the art as having more than one isocyanate group, e.g., di-isocyanate, tri-isocyanate, and tetra-isocyanate. Preferably, the polyisocyanate includes MDI, PPDI, TDI, or a mixture thereof, and more preferably, the polyisocyanate includes MDI. It should be understood that, as used herein, the term MDI includes 4,4′-diphenylmethane diisocyanate, polymeric MDI, carbodiimide-modified liquid MDI, and mixtures thereof and, additionally, that the diisocyanate employed may be “low free monomer,” understood by one of ordinary skill in the art to have lower levels of “free” monomer isocyanate groups, typically less than about 0.1% free monomer isocyanate groups. Examples of “low free monomer” diisocyanates include, but are not limited to Low Free Monomer MDI, Low Free Monomer TDI, and Low Free Monomer PPDI.
The at least one polyisocyanate should have less than about 14% unreacted NCO groups. Preferably, the at least one polyisocyanate has no greater than about 8.0% NCO, more preferably no greater than about 7.8%, and most preferably no greater than about 7.5% NCO with a level of NCO of about 7.2 or 7.0, or 6.5% NCO commonly used.
Any polyol available to one of ordinary skill in the art is suitable for use according to the invention. Exemplary polyols include, but are not limited to, polyether polyols, hydroxy-terminated polybutadiene (including partially/fully hydrogenated derivatives), polyester polyols, polycaprolactone polyols, and polycarbonate polyols. In one preferred embodiment, the polyol includes polyether polyol. Examples include, but are not limited to, polytetramethylene ether glycol (PTMEG), polyethylene propylene glycol, polyoxypropylene glycol, and mixtures thereof. The hydrocarbon chain can have saturated or unsaturated bonds and substituted or unsubstituted aromatic and cyclic groups. Preferably, the polyol of the present invention includes PTMEG.
In another embodiment, polyester polyols are included in the polyurethane material. Suitable polyester polyols include, but are not limited to, polyethylene adipate glycol; polybutylene adipate glycol; polyethylene propylene adipate glycol; o-phthalate-1,6-hexanediol; poly(hexamethylene adipate)glycol; and mixtures thereof. The hydrocarbon chain can have saturated or unsaturated bonds, or substituted or unsubstituted aromatic and cyclic groups.
In another embodiment, polycaprolactone polyols are included in the materials of the invention. Suitable polycaprolactone polyols include, but are not limited to, 1,6-hexanediol-initiated polycaprolactone, diethylene glycol initiated polycaprolactone, trimethylol propane initiated polycaprolactone, neopentyl glycol initiated polycaprolactone, 1,4-butanediol-initiated polycaprolactone, and mixtures thereof. The hydrocarbon chain can have saturated or unsaturated bonds, or substituted or unsubstituted aromatic and cyclic groups.
In yet another embodiment, polycarbonate polyols are included in the polyurethane material of the invention. Suitable polycarbonates include, but are not limited to, polyphthalate carbonate and poly(hexamethylene carbonate)glycol. The hydrocarbon chain can have saturated or unsaturated bonds, or substituted or unsubstituted aromatic and cyclic groups. In one embodiment, the molecular weight of the polyol is from about 200 to about 4000.
Polyamine curatives are also suitable for use in the polyurethane composition of the invention and have been found to improve cut, shear, and impact resistance of the resultant balls. Preferred polyamine curatives include, but are not limited to, 3,5-dimethylthio-2,4-toluenediamine and isomers thereof; 3,5-diethyltoluene-2,4-diamine and isomers thereof, such as 3,5-diethyltoluene-2,6-diamine; 4,4′-bis-(sec-butylamino)-diphenylmethane; 1,4-bis-(sec-butylamino)-benzene, 4,4′-methylene-bis-(2-chloroaniline); 4,4′-methylene-bis-(3-chloro-2,6-diethylaniline); polytetramethyleneoxide-di-p-aminobenzoate; N,N′-dialkyldiamino diphenyl methane; p,p′-methylene dianiline; m-phenylenediamine; 4,4′-methylene-bis-(2-chloroaniline); 4,4′-methylene-bis-(2,6-diethylaniline); 4,4′-methylene-bis-(2,3-dichloroaniline); 4,4′-diamino-3,3′-diethyl-5,5′-dimethyl diphenylmethane; 2,2′, 3,3′-tetrachloro diamino diphenylmethane; trimethylene glycol di-p-aminobenzoate; and mixtures thereof. Preferably, the curing agent of the present invention includes 3,5-dimethylthio-2,4-toluenediamine and isomers thereof, such as ETHACURE® 300, commercially available from Albermarle Corporation of Baton Rouge, La. Suitable polyamine curatives, which include both primary and secondary amines, preferably have molecular weights ranging from about 64 to about 2000.
At least one of a diol, triol, tetraol, or hydroxy-terminated curatives may be added to the aforementioned polyurethane composition. Suitable diol, triol, and tetraol groups include ethylene glycol; diethylene glycol; polyethylene glycol; propylene glycol; polypropylene glycol; lower molecular weight polytetramethylene ether glycol; 1,3-bis(2-hydroxyethoxy)benzene; 1,3-bis-[2-(2-hydroxyethoxy)ethoxy]benzene; 1,3-bis-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}benzene; 1,4-butanediol; 1,5-pentanediol; 1,6-hexanediol; resorcinol-di-(β-hydroxyethyl)ether; hydroquinone-di-(β-hydroxyethyl)ether; and mixtures thereof. Preferred hydroxy-terminated curatives include 1,3-bis(2-hydroxyethoxy)benzene; 1,3-bis-[2-(2-hydroxyethoxy)ethoxy]benzene; 1,3-bis-{2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}benzene; 1,4-butanediol, and mixtures thereof. Preferably, the hydroxy-terminated curatives have molecular weights ranging from about 48 to 2000. It should be understood that molecular weight, as used herein, is the absolute weight average molecular weight and would be understood as such by one of ordinary skill in the art.
Both the hydroxy-terminated and amine curatives can include one or more saturated, unsaturated, aromatic, and cyclic groups. Additionally, the hydroxy-terminated and amine curatives can include one or more halogen groups. The polyurethane composition can be formed with a blend or mixture of curing agents. If desired, however, the polyurethane composition may be formed with a single curing agent.
In a preferred embodiment of the present invention, saturated polyurethanes are used to form one or more of the cover layers, preferably the outer cover layer, and may be selected from among both castable thermoset and thermoplastic polyurethanes.
In this embodiment, the saturated polyurethanes of the present invention are substantially free of aromatic groups or moieties. Saturated polyurethanes suitable for use in the invention are a product of a reaction between at least one polyurethane prepolymer and at least one saturated curing agent. The polyurethane prepolymer is a product formed by a reaction between at least one saturated polyol and at least one saturated diisocyanate. As is well known in the art, that a catalyst may be employed to promote the reaction between the curing agent and the isocyanate and polyol, or the curing agent and the prepolymer.
Saturated diisocyanates which can be used include, without limitation, ethylene diisocyanate; propylene-1,2-diisocyanate; tetramethylene-1,4-diisocyanate; 1,6-hexamethylene-diisocyanate (HDI); 2,2,4-trimethylhexamethylene diisocyanate; 2,4,4-trimethylhexamethylene diisocyanate; dodecane-1,12-diisocyanate; dicyclohexylmethane diisocyanate; cyclobutane-1,3-diisocyanate; cyclohexane-1,3-diisocyanate; cyclohexane-1,4-diisocyanate; 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane; isophorone diisocyanate; methyl cyclohexylene diisocyanate; triisocyanate of HDI; triisocyanate of 2,2,4-trimethyl-1,6-hexane diisocyanate. The most preferred saturated diisocyanates are 4,4′-dicyclohexylmethane diisocyanate and isophorone diisocyanate.
Saturated polyols which are appropriate for use in this invention include without limitation polyether polyols such as polytetramethylene ether glycol and poly(oxypropylene) glycol. Suitable saturated polyester polyols include polyethylene adipate glycol, polyethylene propylene adipate glycol, polybutylene adipate glycol, polycarbonate polyol and ethylene oxide-capped polyoxypropylene diols. Saturated polycaprolactone polyols which are useful in the invention include diethylene glycol-initiated polycaprolactone, 1,4-butanediol-initiated polycaprolactone, 1,6-hexanediol-initiated polycaprolactone; trimethylol propane-initiated polycaprolactone, neopentyl glycol initiated polycaprolactone, and polytetramethylene ether glycol-initiated polycaprolactone. The most preferred saturated polyols are polytetramethylene ether glycol and PTMEG-initiated polycaprolactone.
Suitable saturated curatives include 1,4-butanediol, ethylene glycol, diethylene glycol, polytetramethylene ether glycol, propylene glycol; trimethanolpropane; tetra-(2-hydroxypropyl)-ethylenediamine; isomers and mixtures of isomers of cyclohexyldimethylol, isomers and mixtures of isomers of cyclohexane bis(methylamine); triisopropanolamine; ethylene diamine; diethylene triamine; triethylene tetramine; tetraethylene pentamine; 4,4′-dicyclohexylmethane diamine; 2,2,4-trimethyl-1,6-hexanediamine; 2,4,4-trimethyl-1,6-hexanediamine; diethyleneglycol di-(aminopropyl)ether; 4,4′-bis-(sec-butylamino)-dicyclohexylmethane; 1,2-bis-(sec-butylamino)cyclohexane; 1,4-bis-(sec-butylamino)cyclohexane; isophorone diamine; hexamethylene diamine; propylene diamine; 1-methyl-2,4-cyclohexyl diamine; 1-methyl-2,6-cyclohexyl diamine; 1,3-diaminopropane; dimethylamino propylamine; diethylamino propylamine; imido-bis-propylamine; isomers and mixtures of isomers of diaminocyclohexane; monoethanolamine; diethanolamine; triethanolamine; monoisopropanolamine; and diisopropanolamine. The most preferred saturated curatives are 1,4-butanediol, 1,4-cyclohexyldimethylol and 4,4′-bis-(sec-butylamino)-dicyclohexylmethane.
Alternatively, other suitable polymers include partially or fully neutralized ionomer, metallocene, or other single-site catalyzed polymer, polyester, polyamide, non-ionomeric thermoplastic elastomer, copolyether-esters, copolyether-amides, polycarbonate, polybutadiene, polyisoprene, polystryrene block copolymers (such as styrene-butadiene-styrene), styrene-ethylene-propylene-styrene, styrene-ethylene-butylene-styrene, and the like, and blends thereof. Thermosetting polyurethanes or polyureas are suitable for the outer cover layers of the golf balls of the present invention.
Additionally, polyurethane can be replaced with or blended with a polyurea material. Polyureas are distinctly different from polyurethane compositions, but also result in desirable aerodynamic and aesthetic characteristics when used in golf ball components. The polyurea-based compositions are preferably saturated in nature.
Without being bound to any particular theory, it is now believed that substitution of the long chain polyol segment in the polyurethane prepolymer with a long chain polyamine oligomer soft segment to form a polyurea prepolymer, improves shear, cut, and resiliency, as well as adhesion to other components. Thus, the polyurea compositions of this invention may be formed from the reaction product of an isocyanate and polyamine prepolymer crosslinked with a curing agent. For example, polyurea-based compositions of the invention may be prepared from at least one isocyanate, at least one polyether amine, and at least one diol curing agent or at least one diamine curing agent.
Any polyamine available to one of ordinary skill in the art is suitable for use in the polyurea prepolymer. Polyether amines are particularly suitable for use in the prepolymer. As used herein, “polyether amines” refer to at least polyoxyalkyleneamines containing primary amino groups attached to the terminus of a polyether backbone. Due to the rapid reaction of isocyanate and amine, and the insolubility of many urea products, however, the selection of diamines and polyether amines is limited to those allowing the successful formation of the polyurea prepolymers. In one embodiment, the polyether backbone is based on tetramethylene, propylene, ethylene, trimethylolpropane, glycerin, and mixtures thereof.
Suitable polyether amines include, but are not limited to, methyldiethanolamine; polyoxyalkylenediamines such as, polytetramethylene ether diamines, polyoxypropylenetriamine, and polyoxypropylene diamines; poly(ethylene oxide capped oxypropylene) ether diamines; propylene oxide-based triamines; triethyleneglycoldiamines; trimethylolpropane-based triamines; glycerin-based triamines; and mixtures thereof. In one embodiment, the polyether amine used to form the prepolymer is JEFFAMINE® D2000 (manufactured by Huntsman Chemical Co. of Austin, Tex.).
The molecular weight of the polyether amine for use in the polyurea prepolymer may range from about 100 to about 5000. In one embodiment, the polyether amine molecular weight is about 200 or greater, preferably about 230 or greater. In another embodiment, the molecular weight of the polyether amine is about 4000 or less. In yet another embodiment, the molecular weight of the polyether amine is about 600 or greater. In still another embodiment, the molecular weight of the polyether amine is about 3000 or less. In yet another embodiment, the molecular weight of the polyether amine is between about 1000 and about 3000, and more preferably is between about 1500 to about 2500. Because lower molecular weight polyether amines may be prone to forming solid polyureas, a higher molecular weight oligomer, such as JEFFAMINE® D2000, is preferred.
As briefly discussed above, some amines may be unsuitable for reaction with the isocyanate because of the rapid reaction between the two components. In particular, shorter chain amines are fast reacting. In one embodiment, however, a hindered secondary diamine may be suitable for use in the prepolymer. Without being bound to any particular theory, it is believed that an amine with a high level of stearic hindrance, e.g., a tertiary butyl group on the nitrogen atom, has a slower reaction rate than an amine with no hindrance or a low level of hindrance. For example, 4,4′-bis-(sec-butylamino)-dicyclohexylmethane (CLEARLINK® 1000) may be suitable for use in combination with an isocyanate to form the polyurea prepolymer.
Any isocyanate available to one of ordinary skill in the art is suitable for use in the polyurea prepolymer. Isocyanates for use with the present invention include aliphatic, cycloaliphatic, araliphatic, aromatic, any derivatives thereof, and combinations of these compounds having two or more isocyanate (NCO) groups per molecule. The isocyanates may be organic polyisocyanate-terminated prepolymers. The isocyanate-containing reactable component may also include any isocyanate-functional monomer, dimer, trimer, or multimeric adduct thereof, prepolymer, quasi-prepolymer, or mixtures thereof. Isocyanate-functional compounds may include monoisocyanates or polyisocyanates that include any isocyanate functionality of two or more.
Suitable isocyanate-containing components include diisocyanates having the generic structure: O═C═N—R—N═C═O, where R is preferably a cyclic, aromatic, or linear or branched hydrocarbon moiety containing from about 1 to about 20 carbon atoms. The diisocyanate may also contain one or more cyclic groups or one or more phenyl groups. When multiple cyclic or aromatic groups are present, linear and/or branched hydrocarbons containing from about 1 to about 10 carbon atoms can be present as spacers between the cyclic or aromatic groups. In some cases, the cyclic or aromatic group(s) may be substituted at the 2-, 3-, and/or 4-positions, or at the ortho-, meta-, and/or para-positions, respectively. Substituted groups may include, but are not limited to, halogens, primary, secondary, or tertiary hydrocarbon groups, or a mixture thereof.
Examples of diisocyanates that can be used with the present invention include, but are not limited to, substituted and isomeric mixtures including 2,2′-, 2,4′-, and 4,4′-diphenylmethane diisocyanate; 3,3′-dimethyl-4,4′-biphenylene diisocyanate; toluene diisocyanate; polymeric MDI; carbodiimide-modified liquid 4,4′-diphenylmethane diisocyanate; para-phenylene diisocyanate; meta-phenylene diisocyanate; triphenyl methane-4,4′- and triphenyl methane-4,4′-triisocyanate; naphthylene-1,5-diisocyanate; 2,4′-, 4,4′-, and 2,2-biphenyl diisocyanate; polyphenyl polymethylene polyisocyanate; mixtures of MDI and PMDI; mixtures of PMDI and TDI; ethylene diisocyanate; propylene-1,2-diisocyanate; tetramethylene-1,2-diisocyanate; tetramethylene-1,3-diisocyanate; tetramethylene-1,4-diisocyanate; 1,6-hexamethylene-diisocyanate; octamethylene diisocyanate; decamethylene diisocyanate; 2,2,4-trimethylhexamethylene diisocyanate; 2,4,4-trimethylhexamethylene diisocyanate; dodecane-1,12-diisocyanate; cyclobutane-1,3-diisocyanate; cyclohexane-1,2-diisocyanate; cyclohexane-1,3-diisocyanate; cyclohexane-1,4-diisocyanate; methyl-cyclohexylene diisocyanate; 2,4-methylcyclohexane diisocyanate; 2,6-methylcyclohexane diisocyanate; 4,4′-dicyclohexyl diisocyanate; 2,4′-dicyclohexyl diisocyanate; 1,3,5-cyclohexane triisocyanate; isocyanatomethylcyclohexane isocyanate; 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane; isocyanatoethylcyclohexane isocyanate; bis(isocyanatomethyl)-cyclohexane diisocyanate; 4,4′-bis(isocyanatomethyl)dicyclohexane; 2,4′-bis(isocyanatomethyl)dicyclohexane; isophorone diisocyanate; triisocyanate of HDI; triisocyanate of 2,2,4-trimethyl-1,6-hexane diisocyanate; 4,4′-dicyclohexylmethane diisocyanate; 2,4-hexahydrotoluene diisocyanate; 2,6-hexahydrotoluene diisocyanate; 1,2-, 1,3-, and 1,4-phenylene diisocyanate; aromatic aliphatic isocyanate, such as 1,2-, 1,3-, and 1,4-xylene diisocyanate; meta-tetramethylxylene diisocyanate; para-tetramethylxylene diisocyanate; trimerized isocyanurate of any polyisocyanate, such as isocyanurate of toluene diisocyanate, trimer of diphenylmethane diisocyanate, trimer of tetramethylxylene diisocyanate, isocyanurate of hexamethylene diisocyanate, isocyanurate of isophorone diisocyanate, and mixtures thereof; dimerized uredione of any polyisocyanate, such as uretdione of toluene diisocyanate, uretdione of hexamethylene diisocyanate, and mixtures thereof; modified polyisocyanate derived from the above isocyanates and polyisocyanates; and mixtures thereof.
Examples of saturated diisocyanates that can be used with the present invention include, but are not limited to, ethylene diisocyanate; propylene-1,2-diisocyanate; tetramethylene diisocyanate; tetramethylene-1,4-diisocyanate; 1,6-hexamethylene-diisocyanate; octamethylene diisocyanate; decamethylene diisocyanate; 2,2,4-trimethylhexamethylene diisocyanate; 2,4,4-trimethylhexamethylene diisocyanate; dodecane-1,12-diisocyanate; cyclobutane-1,3-diisocyanate; cyclohexane-1,2-diisocyanate; cyclohexane-1,3-diisocyanate; cyclohexane-1,4-diisocyanate; methyl-cyclohexylene diisocyanate; 2,4-methylcyclohexane diisocyanate; 2,6-methylcyclohexane diisocyanate; 4,4′-dicyclohexyl diisocyanate; 2,4′-dicyclohexyl diisocyanate; 1,3,5-cyclohexane triisocyanate; isocyanatomethylcyclohexane isocyanate; 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane; isocyanatoethylcyclohexane isocyanate; bis(isocyanatomethyl)-cyclohexane diisocyanate; 4,4′-bis(isocyanatomethyl)dicyclohexane; 2,4′-bis(isocyanatomethyl)dicyclohexane; isophorone diisocyanate; triisocyanate of HDI; triisocyanate of 2,2,4-trimethyl-1,6-hexane diisocyanate; 4,4′-dicyclohexylmethane diisocyanate; 2,4-hexahydrotoluene diisocyanate; 2,6-hexahydrotoluene diisocyanate; and mixtures thereof. Aromatic aliphatic isocyanates may also be used to form light stable materials. Examples of such isocyanates include 1,2-, 1,3-, and 1,4-xylene diisocyanate; meta-tetramethylxylene diisocyanate; para-tetramethylxylene diisocyanate; trimerized isocyanurate of any polyisocyanate, such as isocyanurate of toluene diisocyanate, trimer of diphenylmethane diisocyanate, trimer of tetramethylxylene diisocyanate, isocyanurate of hexamethylene diisocyanate, isocyanurate of isophorone diisocyanate, and mixtures thereof; dimerized uredione of any polyisocyanate, such as uretdione of toluene diisocyanate, uretdione of hexamethylene diisocyanate, and mixtures thereof; modified polyisocyanate derived from the above isocyanates and polyisocyanates; and mixtures thereof. In addition, the aromatic aliphatic isocyanates may be mixed with any of the saturated isocyanates listed above for the purposes of this invention.
The number of unreacted NCO groups in the polyurea prepolymer of isocyanate and polyether amine may be varied to control such factors as the speed of the reaction, the resultant hardness of the composition, and the like. For instance, the number of unreacted NCO groups in the polyurea prepolymer of isocyanate and polyether amine may be less than about 14 percent. In one embodiment, the polyurea prepolymer has from about 5 percent to about 11 percent unreacted NCO groups, and even more preferably has from about 6 to about 9.5 percent unreacted NCO groups. In one embodiment, the percentage of unreacted NCO groups is about 3 percent to about 9 percent. Alternatively, the percentage of unreacted NCO groups in the polyurea prepolymer may be about 7.5 percent or less, and more preferably, about 7 percent or less. In another embodiment, the unreacted NCO content is from about 2.5 percent to about 7.5 percent, and more preferably from about 4 percent to about 6.5 percent.
When formed, polyurea prepolymers may contain about 10 percent to about 20 percent by weight of the prepolymer of free isocyanate monomer. Thus, in one embodiment, the polyurea prepolymer may be stripped of the free isocyanate monomer. For example, after stripping, the prepolymer may contain about 1 percent or less free isocyanate monomer. In another embodiment, the prepolymer contains about 0.5 percent by weight or less of free isocyanate monomer.
The polyether amine may be blended with additional polyols to formulate copolymers that are reacted with excess isocyanate to form the polyurea prepolymer. In one embodiment, less than about 30 percent polyol by weight of the copolymer is blended with the saturated polyether amine. In another embodiment, less than about 20 percent polyol by weight of the copolymer, preferably less than about 15 percent by weight of the copolymer, is blended with the polyether amine. The polyols listed above with respect to the polyurethane prepolymer, e.g., polyether polyols, polycaprolactone polyols, polyester polyols, polycarbonate polyols, hydrocarbon polyols, other polyols, and mixtures thereof, are also suitable for blending with the polyether amine. The molecular weight of these polymers may be from about 200 to about 4000, but also may be from about 1000 to about 3000, and more preferably are from about 1500 to about 2500.
The polyurea composition can be formed by crosslinking the polyurea prepolymer with a single curing agent or a blend of curing agents. The curing agent of the invention is preferably an amine-terminated curing agent, more preferably a secondary diamine curing agent so that the composition contains only urea linkages. In one embodiment, the amine-terminated curing agent may have a molecular weight of about 64 or greater. In another embodiment, the molecular weight of the amine-curing agent is about 2000 or less. As discussed above, certain amine-terminated curing agents may be modified with a compatible amine-terminated freezing point depressing agent or mixture of compatible freezing point depressing agents.
Suitable amine-terminated curing agents include, but are not limited to, ethylene diamine; hexamethylene diamine; 1-methyl-2,6-cyclohexyl diamine; tetrahydroxypropylene ethylene diamine; 2,2,4- and 2,4,4-trimethyl-1,6-hexanediamine; 4,4′-bis-(sec-butylamino)-dicyclohexylmethane; 1,4-bis-(sec-butylamino)-cyclohexane; 1,2-bis-(sec-butylamino)-cyclohexane; derivatives of 4,4′-bis-(sec-butylamino)-dicyclohexylmethane; 4,4′-dicyclohexylmethane diamine; 1,4-cyclohexane-bis-(methylamine); 1,3-cyclohexane-bis-(methylamine); diethylene glycol di-(aminopropyl)ether; 2-methylpentamethylene-diamine; diaminocyclohexane; diethylene triamine; triethylene tetramine; tetraethylene pentamine; propylene diamine; 1,3-diaminopropane; dimethylamino propylamine; diethylamino propylamine; dipropylene triamine; imido-bis-propylamine; monoethanolamine, diethanolamine; triethanolamine; monoisopropanolamine, diisopropanolamine; isophoronediamine; 4,4′-methylenebis-(2-chloroaniline); 3,5; dimethylthio-2,4-toluenediamine; 3,5-dimethylthio-2,6-toluenediamine; 3,5-diethylthio-2,4-toluenediamine; 3,5; diethylthio-2,6-toluenediamine; 4,4′-bis-(sec-butylamino)-diphenylmethane and derivatives thereof; 1,4-bis-(sec-butylamino)-benzene; 1,2-bis-(sec-butylamino)-benzene; N,N′-dialkylamino-diphenylmethane; N,N,N′,N′-tetrakis(2-hydroxypropyl)ethylene diamine; trimethyleneglycol-di-p-aminobenzoate; polytetramethyleneoxide-di-p-aminobenzoate; 4,4′-methylenebis-(3-chloro-2,6-diethyleneaniline); 4,4′-methylenebis-(2,6-diethylaniline); meta-phenylenediamine; paraphenylenediamine; and mixtures thereof. In one embodiment, the amine-terminated curing agent is 4,4′-bis-(sec-butylamino)-dicyclohexylmethane.
Suitable saturated amine-terminated curing agents include, but are not limited to, ethylene diamine; hexamethylene diamine; 1-methyl-2,6-cyclohexyl diamine; tetrahydroxypropylene ethylene diamine; 2,2,4- and 2,4,4-trimethyl-1,6-hexanediamine; 4,4′-bis-(sec-butylamino)-dicyclohexylmethane; 1,4-bis-(sec-butylamino)-cyclohexane; 1,2-bis-(sec-butylamino)-cyclohexane; derivatives of 4,4′-bis-(sec-butylamino)-dicyclohexylmethane; 4,4′-dicyclohexylmethane diamine; 4,4′-methylenebis-(2,6-diethylaminocyclohexane; 1,4-cyclohexane-bis-(methylamine); 1,3-cyclohexane-bis-(methylamine); diethylene glycol di-(aminopropyl)ether; 2-methylpentamethylene-diamine; diaminocyclohexane; diethylene triamine; triethylene tetramine; tetraethylene pentamine; propylene diamine; 1,3-diaminopropane; dimethylamino propylamine; diethylamino propylamine; imido-bis-propylamine; monoethanolamine, diethanolamine; triethanolamine; monoisopropanolamine, diisopropanolamine; isophoronediamine; triisopropanolamine; and mixtures thereof. In addition, any of the polyether amines listed above may be used as curing agents to react with the polyurea prepolymers.
Cover layers of the inventive golf ball may also be formed from ionomeric polymers, preferably highly-neutralized ionomers (HNP). In a preferred embodiment, at least one intermediate layer of the golf ball is formed from an HNP material or a blend of HNP materials. The acid moieties of the HNP's, typically ethylene-based ionomers, are preferably neutralized greater than about 70%, more preferably greater than about 90%, and most preferably at least about 100%. The HNP's can be also be blended with a second polymer component, which, if containing an acid group, may be neutralized in a conventional manner, by the organic fatty acids of the present invention, or both. The second polymer component, which may be partially or fully neutralized, preferably comprises ionomeric copolymers and terpolymers, ionomer precursors, thermoplastics, polyamides, polycarbonates, polyesters, polyurethanes, polyureas, thermoplastic elastomers, polybutadiene rubber, balata, metallocene-catalyzed polymers (grafted and non-grafted), single-site polymers, high-crystalline acid polymers, cationic ionomers, and the like. HNP polymers typically have a material hardness of between about 20 and about 80 Shore D, and a flexural modulus of between about 3,000 psi and about 200,000 psi.
In one embodiment of the present invention the HNP's are ionomers and/or their acid precursors that are preferably neutralized, either filly or partially, with organic acid copolymers or the salts thereof. The acid copolymers are preferably α-olefin, such as ethylene, C 3-8 α,β-ethylenically unsaturated carboxylic acid, such as acrylic and methacrylic acid, copolymers. They may optionally contain a softening monomer, such as alkyl acrylate and alkyl methacrylate, wherein the alkyl groups have from 1 to 8 carbon atoms.
The acid copolymers can be described as E/X/Y copolymers where E is ethylene, X is an α,β-ethylenically unsaturated carboxylic acid, and Y is a softening comonomer. In a preferred embodiment, X is acrylic or methacrylic acid and Y is a C 1-8 alkyl acrylate or methacrylate ester. X is preferably present in an amount from about 1 to about 35 weight percent of the polymer, more preferably from about 5 to about 30 weight percent of the polymer, and most preferably from about 10 to about 20 weight percent of the polymer. Y is preferably present in an amount from about 0 to about 50 weight percent of the polymer, more preferably from about 5 to about 25 weight percent of the polymer, and most preferably from about 10 to about 20 weight percent of the polymer.
Specific acid-containing ethylene copolymers include, but are not limited to, ethylene/acrylic acid/n-butyl acrylate, ethylene/methacrylic acid/n-butyl acrylate, ethylene/methacrylic acid/iso-butyl acrylate, ethylene/acrylic acid/iso-butyl acrylate, ethylene/methacrylic acid/n-butyl methacrylate, ethylene/acrylic acid/methyl methacrylate, ethylene/acrylic acid/methyl acrylate, ethylene/methacrylic acid/methyl acrylate, ethylene/methacrylic acid/methyl methacrylate, and ethylene/acrylic acid/n-butyl methacrylate. Preferred acid-containing ethylene copolymers include, ethylene/methacrylic acid/n-butyl acrylate, ethylene/acrylic acid/n-butyl acrylate, ethylene/methacrylic acid/methyl acrylate, ethylene/acrylic acid/ethyl acrylate, ethylene/methacrylic acid/ethyl acrylate, and ethylene/acrylic acid/methyl acrylate copolymers. The most preferred acid-containing ethylene copolymers are, ethylene/(meth) acrylic acid/n-butyl, acrylate, ethylene/(meth)acrylic acid/ethyl acrylate, and ethylene/(meth) acrylic acid/methyl acrylate copolymers.
Ionomers are typically neutralized with a metal cation, such as Li, Na, Mg, K, Ca, or Zn. It has been found that by adding sufficient organic acid or salt of organic acid, along with a suitable base, to the acid copolymer or ionomer, however, the ionomer can be neutralized, without losing processability, to a level much greater than for a metal cation. Preferably, the acid moieties are neutralized greater than about 80%, preferably from 90-100%, most preferably 100% without losing processability. This accomplished by melt-blending an ethylene α,β-ethylenically unsaturated carboxylic acid copolymer, for example, with an organic acid or a salt of organic acid, and adding a sufficient amount of a cation source to increase the level of neutralization of all the acid moieties (including those in the acid copolymer and in the organic acid) to greater than 90%, (preferably greater than 100%).
The organic acids of the present invention are aliphatic, mono- or multi-functional (saturated, unsaturated, or multi-unsaturated) organic acids. Salts of these organic acids may also be employed. The salts of organic acids of the present invention include the salts of barium, lithium, sodium, zinc, bismuth, chromium, cobalt, copper, potassium, strontium, titanium, tungsten, magnesium, cesium, iron, nickel, silver, aluminum, tin, or calcium, salts of fatty acids, particularly stearic, behenic, erucic, oleic, linoelic or dimerized derivatives thereof. It is preferred that the organic acids and salts of the present invention be relatively non-migratory (they do not bloom to the surface of the polymer under ambient temperatures) and non-volatile (they do not volatilize at temperatures required for melt-blending).
The ionomers of the invention may also be more conventional ionomers, i.e., partially-neutralized with metal cations. The acid moiety in the acid copolymer is neutralized about 1 to about 90%, preferably at least about 20 to about 75%, and more preferably at least about 40 to about 70%, to form an ionomer, by a cation such as lithium, sodium, potassium, magnesium, calcium, barium, lead, tin, zinc, aluminum, or a mixture thereof.
A moisture vapor barrier layer, such as disclosed in U.S. Pat. Nos. 6,632,147; 6,932,720; 7,004,854; and 7,182,702, all of which are incorporated by reference herein in their entirety, are optionally employed between the cover layer and the core. The moisture barrier layer may be disposed between the outer core layer and the cover layer. The moisture vapor barrier protects the inner and outer cores from degradation due to exposure to moisture, for example water, and extends the usable life of the golf ball. The moisture vapor transmission rate of the moisture barrier layer is selected to be less than the moisture vapor transmission rate of the cover layer. The moisture barrier layer has a specific gravity of from about 1.1 to about 1.2 and a thickness of less than about 0.03 inches. Suitable materials for the moisture barrier layer include a combination of a styrene block copolymer and a flaked metal, for example aluminum flake.
Unless otherwise expressly specified, all of the numerical ranges, amounts, values and percentages such as those for amounts of materials, and others in the specification may be read as if prefaced by the word “about” even though the term “about” may not expressly appear with the value, amount or range. Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements. Furthermore, when numerical ranges of varying scope are set forth herein, it is contemplated that any combination of these values inclusive of the recited values may be used.
While it is apparent that the illustrative embodiments of the invention disclosed herein fulfill the preferred embodiments of the present invention, it is appreciated that numerous modifications and other embodiments may be devised by those skilled in the art. Examples of such modifications include reasonable variations of the numerical values and/or materials and/or components discussed above. Hence, the numerical values stated above and claimed below specifically include those values and the values that are approximate to those stated and claimed values. Therefore, it will be understood that the appended claims are intended to cover all such modifications and embodiments, which would come within the spirit and scope of the present invention.
The invention described and claimed herein is not to be limited in scope by the specific embodiments herein disclosed, since these embodiments are intended as illustrations of several aspects of the invention. Any equivalent embodiments are intended to be within the scope of this invention. Indeed, various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description. For example, the compositions of the present invention may be used in a variety of equipment. Such modifications are also intended to fall within the scope of the appended claims.
While any of the embodiments herein may have any known dimple number and pattern, a preferred number of dimples is 252 to 456, and more preferably is 330 to 392. The dimples may comprise any width, depth, and edge angle disclosed in the prior art and the patterns may comprises multitudes of dimples having different widths, depths and edge angles. The parting line configuration of said pattern may be either a straight line or a staggered wave parting line (SWPL). Most preferably the dimple number is 330, 332, or 392 and comprises 5 to 7 dimples sizes and the parting line is a SWPL.
In any of these embodiments the single-layer core may be replaced with a 2 or more layer core wherein at least one core layer has a negative hardness gradient. Other than in the operating examples, or unless otherwise expressly specified, all of the numerical ranges, amounts, values and percentages such as those for amounts of materials and others in the specification may be read as if prefaced by the word “about” even though the term “about” may not expressly appear with the value, amount or range.
Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.
While it is apparent that the illustrative embodiments of the invention disclosed herein fulfill the objective stated above, it is appreciated that numerous modifications and other embodiments may be devised by those skilled in the art. Therefore, it will be understood that the appended claims are intended to cover all such modifications and embodiments, which would come within the spirit and scope of the present invention.
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The present invention is directed to an improved multi-layered core golf ball wherein each core layer comprises its own specific hardness gradient (positive, negative or a combination) in addition to an overall specific hardness gradient from one core layer to the next.
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CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This patent application claims the benefit of U.S. Provisional Patent Application No. 60/602,062, filed Aug. 17, 2004, the teachings and disclosure of which are incorporated herein, in their entireties, by reference.
FIELD OF THE INVENTION
[0002] This invention relates to control systems in buildings, and more particularly to connecting a controller to a wiring circuit of a building.
BACKGROUND OF THE INVENTION
[0003] Modern buildings typically include a plurality of controllers, located throughout the building, for providing de-centralized control of building subsystems, such as heating, ventilating and air conditioning (HVAC) systems. Such controllers typically are connected, via an electrical circuit external to the controller, to control panels and/or computers located remotely from the controller which supply electrical power and control signals to the controller, which, in turn, redirects the power and control signals to the equipment connected to the controller.
[0004] Such controllers typically include active and passive electrical and/or electronic components for performing localized signal conditioning and control functions.
[0005] Such controllers are susceptible to being damaged during construction of the building, and/or installation of the control system into a building. It is desirable, therefore, to provide an apparatus and method for progressively installing the controller, during initial rough-in of the building and sequential finishing operations, to limit exposure of the controller, and associated interconnection equipment, to potential damage during construction. It is further desirable, that such an improved method and apparatus provide a compact overall package of the controller, and its related interconnecting elements, which is preferably relatively flat and accessible from one side of a wall upon which the controller is mounted, and in a form which minimizes the projection of the controller and its related interconnecting devices away from the wall.
[0006] Prior apparatuses and methods for mounting controllers in buildings through utilization of traditional methods, such as plugging circuit cards into connectors extending axially from a back plane, are not entirely satisfactory in meeting the desires laid out above.
BRIEF SUMMARY OF THE INVENTION
[0007] The invention provides an improved apparatus and method for operatively connecting a controller to an external circuit, by connecting the external circuit to a circuit board mounted for slideable movement into operative engagement with a connection element disposed on a side surface of the controller. The circuit card may be slideably supported in a receiver adapted for positioning the controller with respect to the circuit card. By making the connections between the controller and the external circuit with a slideably movable circuit card engaging a connection element disposed on a side surface of the controller, rather than making such a connection with a connector on a rear surface of the controller, as was often done in the past, the invention provides an overall package which is relatively flat, and readily attachable to a mounting surface, such as the wall of an electrical enclosure.
[0008] An apparatus and method, according to the invention, allow for sequentially installing the controller through the steps of: attaching a receiver, according to the invention, to a support structure; slideably attaching the circuit card to the receiver; attaching conductor elements of the external circuit to the circuit card; positioning the controller on the receiver; and sliding the circuit card simultaneously with respect to both the controller and the receiver, to thereby provide operative connection with the connection element on the side of the controller.
[0009] Through such a sequence, the receiver may be installed very early in the building construction when rough-in operations, such as installation of conduit and pulling wires and/or fiber optic or other power and signal carriers through the conduit, are being accomplished. Once the building has been further completed, to an intermediate state of completion, the circuit card may be attached to the receiver and the wires and/or fiber optic or other power and control carriers connected to the circuit card. When construction of the building has been largely completed, the controller may be installed by positioning it on the receiver, and sliding the circuit card into operative connection with the controller.
[0010] Engagement of the circuit card with the controller may serve to at least partially retain the controller on the receiver. The receiver may also be configured for holding the controller in position thereon, prior to engagement of the circuit card with the controller. The receiver may engage and hold the controller in position through gravitational force acting on the controller, or alternatively, the receiver and controller may engage one another through a snap-together connection.
[0011] In the form of the invention, an apparatus for operatively connecting a controller, having a connection element through an external circuit, uses a slideably movable circuit card, defining a card plane and having a mating connection element configured for engagement with the connection element of the controller along a connection axis extending substantially parallel to the card plane. The apparatus may include a receiver for slideably supporting the circuit card, positioning the controller with respect to the card plane, and guiding the circuit card in such a manner that the mating connection element of the circuit card moves substantially along the connection axis between an engaged and a disengaged position of the connection element and mating connection element, as the circuit card is slidingly moved with respect to both the receiver and controller while being supported by the receiver. The apparatus may further include the circuit card and/or the controller. The apparatus may further include a cable support adapted for operative attachment thereto of the receiver. The cable support may take the form of a chassis for enclosing the receiver, controller, and circuit card.
[0012] In some forms of an apparatus, according to the invention, the controller may also include a second connection element, and the apparatus may further include a second circuit card defining a second card plane and having a second mating connection element configured for engagement with the second connection element of the controller along a second connection axis extending substantially parallel to the second card plane. The receiver may slidingly support the second circuit card, position the controller simultaneously with respect to the first and second card planes, and guide the second circuit card in such a manner that the second mating connection element of the second circuit card moves substantially along the second connection axis between an engaged and a disengaged position of the second connection element and the second mating connection element as the second circuit card is slidingly moved with respect to both the receiver and the controller while being supported by the receiver. The receiver may slidingly support the first and second circuit cards in a common sliding plane, with the first and second circuit cards disposed on opposite sides of the controller, with the first and second connection elements of the controller facing in substantially opposite directions, such that the first and second connections of the controller are engaged by moving the first and second circuit cards toward the controller, and such that the first and second connections of the controller are disengaged by moving the circuit cards away from the controller.
[0013] A receiver, according to the invention, may further include one or more tracks for receiving and retaining one or more circuit cards therein. An apparatus, according to the invention, may further include one or more retainers for securing the circuit cards in the tracks.
[0014] The invention may take the form of a method for constructing and/or installing and/or repairing or maintaining an apparatus according to the invention.
[0015] An apparatus, according to the invention, may also be provided in the form of a kit including one or more of a receiver, circuit card, controller, circuit card retainer, and cable support according to the invention.
[0016] Other aspects, objects and advantages of the invention will be apparent from the following detailed description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention. In the drawings:
[0018] FIG. 1 is an exploded perspective view of a first exemplary embodiment of a controller connection apparatus, according to the invention;
[0019] FIG. 2 is a perspective view of the exemplary embodiment of the controller connection apparatus of FIG. 1 , with various components thereof shown in an assembled position;
[0020] FIGS. 3, 4 , 6 , and 8 sequentially illustrate the manner in which the first exemplary embodiment of the invention, as shown in FIGS. 1 and 2 , may be progressively installed and connected into a control circuit in a building, according to a method of the invention.
[0021] FIG. 5 is an enlarged perspective view of a portion of the first exemplary embodiment of the invention, illustrating the manner in which a circuit card, according to the invention, is connected to a receiver according to the invention.
[0022] FIG. 7 is an enlarged perspective view of a portion of the first exemplary embodiment of the invention, illustrating the manner in which a controller, of the first exemplary embodiment, is positioned and supported by a receiver of the first exemplary embodiment.
[0023] FIG. 9 is a perspective illustration of a second exemplary embodiment of a control connection apparatus, according to the invention.
[0024] FIG. 10 is a schematic cross-sectional illustration of a snap-together connection between a controller and a receiver of the second exemplary embodiment of the invention.
[0025] FIG. 11 is an enlarged perspective view illustrating handles, according to the invention, for facilitating engagement and disengagement of connection elements, according to the invention.
[0026] FIG. 12 is a cross-sectional view taken along line 12 - 12 in FIG. 10 .
[0027] While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.
DETAILED DESCRIPTION OF THE INVENTION
[0028] FIG. 1 shows a first exemplary embodiment of a controller connection apparatus 100 , according to the invention. The first exemplary embodiment of the controller apparatus 100 includes the controller 102 , a receiver 104 , first and second control cards 106 , 108 , four circuit card retainers 110 , and a two-part enclosure having a cable-supporting housing 112 and a cover 114 .
[0029] As shown in FIGS. 1, 2 , 6 and 8 , the controller 102 , of the exemplary embodiment of the controller connection apparatus 100 , includes first and second connection elements, in the form of multi-pin electrical connector halves 116 , 118 , extending in opposite directions, from opposite sides of the controller 102 .
[0030] The first circuit card 106 includes a printed circuit board which defines a card plane 120 of the first circuit card, and includes a mating connection element, in the form of a multi-pin connector half 122 , which is configured for engagement with the first connection element 116 of the controller 102 , along a first connection axis 124 which extends substantially parallel to the first card plane 120 , when the controller 102 and first circuit card 106 are operatively connected to the receiver 104 , in the manner described below in more detail.
[0031] In similar fashion, the second circuit card 108 includes a printed circuit board defining a second card plane 126 , and also includes a second mating connection element 128 , in the form of a multi-pin electrical connector half configured for engagement with the second connection element 118 of the controller 102 along a second connection axis 130 , which extends substantially parallel to the second card plane 126 , when the second circuit card 108 and controller 102 are operatively installed in the receiver 104 , in the manner described in more detail below.
[0032] As shown in FIG. 3 , during rough-in construction of a building, the cable supporting housing 112 , of the enclosure, of the exemplary embodiment, is attached to a substantially vertical wall or support structure of the building. The cable support housing 112 includes a plurality of knock-outs 132 (see FIG. 2 ), which can be removed to allow attachment of conduit runs 134 to the cable support housing 112 . Power and signal conductors 136 , such as electrical wires and/or fiber optic cables, may then be pulled through the conduit runs 134 into the cable support housing 112 , prior to closing in the walls of the building through which the conduit may need to be run. The receiver 104 may also be installed at the same time as the cable support housing 112 , using a single set of fasteners (not shown) for attaching both the receiver 104 and the cable support housing 112 to the support structure of the building. Alternatively, the receiver 104 may be installed at a later stage of the construction.
[0033] As shown in FIG. 4 , after the walls of the building are closed in, or at another appropriate intermediate stage of the construction of the building, the first and second control cards 106 , 108 may be installed in the receiver 104 , and the power and/or signal conducting elements 136 may be trimmed to length and connected to terminal strips and connectors 138 , 139 which are part of the first and second control cards 106 , 108 .
[0034] As illustrated in FIGS. 1 and 5 , the receiver 104 , of the first exemplary embodiment of a controller connection apparatus 100 , according to the invention, includes an upper and a lower track rails 140 , 142 each having respective track portions 144 , 146 for receiving and retaining within the tracks 144 , 146 the upper and lower ends respectively of the first and second circuit cards 106 , 108 . Threaded studs 148 project outward from the track rails 140 , 142 , through U-shaped slots 150 in the circuit cards 106 , 108 , adjacent the upper and lower ends thereof, for threaded engagement with the circuit card retainers 110 , which take the form of elongated thumb-screws in the exemplary embodiment.
[0035] The tracks 144 , 146 and the upper and lower ends of the circuit cards 106 , 108 are cooperatively configured in such a manner that, with the circuit card retainers 110 removed, the circuit cards 106 , 108 can be inserted at an angle into the tracks 144 , 146 and then moved to a non-angled position with respect to the tracks 144 , 146 , in which the circuit cards 106 , 108 are retained within the tracks 144 , 146 . When the retainers 110 are threaded onto the studs 148 , to a position of close proximity to the first and second circuit cards 106 , 108 , when the circuit cards 106 , 108 are positioned within the tracks 144 , 146 , the retainers 110 prevent the circuit cards 106 , 108 , from being tilted enough with respect to the tracks 144 , 146 to allow removal of the circuit cards 106 , 108 .
[0036] The tracks 144 , 146 in the receiver 104 of the first exemplary embodiment of the controller connection apparatus 100 , according to the invention, are configured and oriented to slidingly support the first and second circuit cards 106 , 108 , and guide the circuit cards 106 , 108 in such a manner that the second mating connection elements 122 , 128 move substantially and respectively along the first and second connection axes 124 , 130 between respective engaged positions, when the circuit cards 106 , 108 are moved inward toward an innermost extent of their travel within the tracks 144 , 146 , and respective disengaged positions when the circuit cards 106 , 108 are moved outward from the controller to an outermost extent of their respective travels within the tracks 144 , 146 .
[0037] As shown in FIG. 1 , a handle 152 , in the form of an L-shaped fin, is attached to each of the first and second mating connection elements 122 , 128 , to facilitate movement of the circuit cards 106 , 108 toward and away from the controller 102 , for engagement and disengagement of the first and second mating connection elements 122 , 128 , with the first and second connection elements 116 , 118 , respectively, of the controller 102 .
[0038] As shown in FIG. 7 , the upper track rail 140 also includes a pair of hooks 154 for engaging corresponding D-shaped openings 156 in the rear surface of the controller 102 , in such a manner that the receiver 104 positions the controller simultaneously with respect to the first and second card planes 120 , 126 and the first and second connection axes 124 , 130 . The hooks 154 , of the first exemplary embodiment of the invention, are configured for engaging and holding the controller 102 in position on the receiver 104 , when the connection elements 116 , 118 and mating connection elements 122 , 128 are not engaged, through gravitational force acting on the controller 102 .
[0039] As shown in FIG. 6 , when construction on the building has progressed to a point where it is desirable and safe to do so, the first and second circuit cards 106 , 108 are moved outward toward the outermost extent of their travel in the tracks 144 , 146 , and the controller 102 is placed in position between the circuit cards 106 , 108 on the receiver 104 . The first and second circuit cards 106 , 108 are then moved inward, as shown in FIG. 8 , toward the controller 102 , to thereby engage the first and second mating connector elements 122 , 128 on the first and second control cards 106 , 108 with the first and second connection elements 116 , 118 , respectively, on the controller 102 , to thereby complete installation and connection of the controller 102 into the external circuit of the building.
[0040] FIGS. 9 and 10 show a second exemplary embodiment of a controller connection apparatus 200 , according to the invention. The second exemplary embodiment of the controller connection apparatus 200 embodies may of the same aspects and elements of the invention described above with regard to the first exemplary embodiment 100 of the invention, except that the controller 202 and receiver 204 of the second embodiment engage one another through a snap-together connection, as illustrated at 206 , rather than using the hooks 154 and D-shaped openings 156 of the first exemplary embodiment of the controller connection apparatus 100 , described above. The snap-together connection 206 provides an alternate means of securing the controller 202 in position on the receiver 204 , prior to engagement of the controller 202 by circuit boards 208 , 210 , without reliance upon gravitational force acting on the controller 202 . As a result of this configuration, the second embodiment of the invention 200 may be preferable where the support structure to which the receiver 204 is attached is not substantially vertical.
[0041] As shown in FIG. 11 , the circuit cards 208 , 210 of the second exemplary embodiment of the invention 200 also include handles 212 , in the form of an L-shaped fin, attached to the mating connection elements 214 to facilitate movement of the circuit cards 208 , 210 toward and away from the controller 202 , for electrically connecting the circuit cards 208 , 210 with the controller 202 .
[0042] Although the invention has been described herein with reference to the first and second exemplary embodiments thereof, it will be understood, by those having skill in the art, that the invention may be practiced in many other forms. For example, in some embodiments of the invention, a receiver, one or more circuit cards, and a controller, according to the invention, may be attached directly to a support structure, or installed inside of an electrical cabinet, for example, without utilizing an enclosure 112 , 114 according to the invention.
[0043] As illustrated in FIG. 5 , it is further contemplated, that in practicing the invention, circuit cards, according to the invention, may include electrical and/or electronic circuit components 158 , 160 , in addition to external circuit connectors, such as the terminal strips 138 and connectors 139 utilized in the exemplary embodiments described herein. For clarity of illustration in the drawings, the electronic and/or electronic circuit components 158 , 160 are only shown in the enlarged view of FIG. 5 . It is understood, however, that in many embodiments of the invention, including the two exemplary embodiments 100 , 200 described herein, the slidable circuit cards 106 , 108 , 208 , 210 , for example, may include electrical and/or electronic circuit components in the manner illustrated in FIG. 5 specifically with regard to the circuit card 106 of the first exemplary embodiment 100 described herein.
[0044] The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) is to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.
[0045] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.
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A method and apparatus are provided for operatively connecting a controller to an external circuit, by connecting the external circuit to a circuit card mounted for slidable movement into operative engagement with a connection element disposed on a side surface of the controller. The circuit card is slidably supported in a receiver adapted for positioning the controller with respect to the circuit card.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of U.S. application Ser. No. 10/401,224, filed Mar. 26, 2003, the contents of the entirety of which are herein incorporated by this reference.
TECHNICAL FIELD
[0002] This invention relates generally to medical devices and associated methods such as measuring glucose for ongoing diabetes management. The invention described herein can also be used for enzymatic determination of other analytes. This invention provides a particularly useful implantable biosensor.
BACKGROUND OF THE INVENTION
[0003] Heretofore, treatment and management of diabetes has been undertaken through many and varied techniques. Formerly, glucose in urine was measured, though recognized as less than adequate due to the time delay inherent in the metabolism and voiding process. Currently, the approach predominantly used for self-monitoring of blood glucose requires periodic pricks of the skin with a needle, whereby a blood sample is obtained and tested directly to provide information about blood glucose levels. This information is then utilized as a basis from which to schedule the administration of insulin to maintain glucose equilibrium within the patient. Direct measurement of glucose levels in periodic blood samples from diabetes patients provides reasonably useful information about insulin levels at certain selected points in time. However, the dynamic nature of blood glucose chemistry and the complexity of factors influencing blood sugar levels render such periodic information less than optimal.
[0004] The glucose level in the subcutaneous interstitial fluid very closely approximates the glucose level in the blood, with a negligible time lag. The variables of patient food selection, physical activity and insulin dosage, regime and protocol for a person with diabetes each have a dynamic impact on physiologic balance within the patient's body that can change dramatically over a short period of time. If the net result of changes in these variables and dynamics results in disequilibrium expressed as too much glucose (“hyperglycemia”), then more insulin is required, whereas too little glucose (“hypoglycemia”) requires immediate intervention to raise the glucose levels. A deleterious impact on physiology follows either such disequilibrium.
[0005] Hyperglycemia is the source of most of the long-term consequences of diabetes, such as blindness, nerve degeneration, and kidney failure. Hypoglycemia, on the other hand, poses the more serious short-term danger. Hypoglycemia can occur at any time of the day or night and can cause the patient to lose consciousness. Guarding against hypoglycemia may require frequent monitoring of blood glucose levels and render the skin-prick approach tedious, painful and, in some cases, impractical. Even diligent patients who perform finger-sticking procedures many times each day achieve only a poor approximation of continuous monitoring. Accordingly, extensive attention has been given to development of improved means of monitoring patient glucose levels for treatment of diabetes.
[0006] Many efforts to continuously monitor glucose levels have involved implantable electrochemical biosensors. These amperometric sensors utilize an immobilized form of the enzyme glucose oxidase to catalyze the conversion of oxygen and glucose to gluconic acid and hydrogen peroxide. Such sensors may be used to measure hydrogen peroxide resulting from the enzymatic reaction. Alternatively, these glucose oxidase-based biosensors measure oxygen consumption to infer glucose concentrations.
[0007] Typical implantable, subcutaneous needle-type biosensors are disclosed in various publications, such as the following examples: “An Amperometric Needle-type Glucose Sensor Tested in Rats and Man,” by D. R. Matthews, E. Bown, T. W. Beck, E. Plotkin, L. Lock, E. Gosden, and M. Wickham, which discloses an amperometric glucose-measuring 25-gauge (0.5 mm diameter) needle-type sensor using a glucose oxidase and dimethyl ferrocene paste behind a semipermeable membrane situated over a window in the needle, “Performance of Subcutaneously Implanted Needle-Type Glucose Sensors Employing a Novel Trilayer Coating,” by Francis Moussy, D. Jed Harrison, Darryl W. O'Brien, and Ray V. Rajotte, which teaches a miniature, needle-type glucose sensor utilizing a perfluorinated ionomer, Nafion, as a protective, biocompatible, outer coating, and poly(o-phenylenediamine) as an inner coating to reduce interference by small, electroactive compounds. Glucose oxidase immobilized in a bovine serum albumin matrix was sandwiched between these coatings. The entire assembly of a platinum working electrode and an Ag/AgCl reference electrode was 0.5 mm in diameter and could be inserted subcutaneously through an 18-gauge needle. Other examples include, “Needle Enzyme Electrodes for Biological Studies,” by S. J. Churchouse, C. M. Battersby, W. H. Mullen and P. M. Vadgama, which presents yet another needle enzyme electrode characterized as the most promising approach to miniaturization for invasive use, “A Miniaturized Nafion-based Glucose Sensor,” by F. Moussy, D. J. Harrison, and R. V. Rajotte, which, while teaching a high sensitivity (due in part to greater surface area of the electrode) needle-type sensor with a spear-shaped point, acknowledges the need for more protection against abrasion, “Design and In Vitro Studies of a Needle-Type Glucose Sensor for Subcutaneous Monitoring,” by Dilbir S. Bindra, Yanan Zhang, George S. Wilson, Robert Sternberg, Daniel R. Thevenot, Dinah Moatti and Gerard Reach, which sets forth yet another needle-type glucose microsensor having a 26-gauge (0.45-mm) outside diameter.
[0008] Additional needle-type implantable biosensors are disclosed in certain United States patent documents. Relevant documents include: “Subcutaneous Glucose Electrode” to Heller et al., U.S. Pat. No. 6,329,161 B1; “Subcutaneous Implantable Sensor Set Having the Capability to Remove Deliver Fluids to an Insertion Site” to Mastrototaro et al., U.S. Pat. No. 5,951,521; “Transcutaneous Sensor Insertion Set” to Halili et al., U.S. Pat. No. 5,586,553; “Transcutaneous Sensor Insertion Set” to Cheney, II et al., U.S. Pat. No. 5,568,806; “Transcutaneous Sensor Insertion Set” to Lord et. al., U.S. Pat. No. 5,390,671; and “Implantable Glucose Sensor” to Wilson et al., U.S. Pat. No. 5,165,407.
[0009] To provide continuous measurement, biosensors can be placed for extended periods of time in various locations within the body. One method of placement is percutaneously with an indwelling sensor having an attached external wire associated with a readout device. A risk of infection is associated with percutaneous biosensors, and they must typically be replaced at regular intervals because of the risk of infection at the insertion site.
[0010] Another problem with implanted sensors is irritation of the tissues surrounding the implanted biosensors. Such irritation is typically due, in part, to the lateral rigidity of prior art biosensors. Related to this problem is the scarring of surrounding tissue due not only to rigidity but also to abrupt edges associated with the implants. Scar tissue surrounding reference electrodes of the prior art is not desirable, but may be tolerated in some cases. However, scar tissue can be materially detrimental to the sensor function in the vicinity of the working electrode because it impedes the diffusion of oxygen and glucose.
[0011] Further, to protect itself against a perceived invader, the body commonly experiences a foreign body reaction by encapsulating the implanted biosensors with protein, which may shorten the life of the implant and adversely affect the accuracy of information provided. The size of the sensor may also be regarded as a problem; smaller is better for comfort. Further yet, interfering compounds, such as, for example, ascorbic acid, and acetaminophen, can reduce the accuracy of prior art amperometric glucose sensors given the membranes selected historically to envelop such sensors. Additionally, the quantity of dissolved oxygen is limited at high glucose concentrations, thus leading to nonlinear output of sensor signals at high glucose concentrations.
[0012] A need remains for a sensor including a miniaturized probe of suitable materials and characteristics that may facilely be placed percutaneously. A need exists for a miniaturized, albeit durable, implantable biosensor percutaneously deployable wherein irritation to tissues surrounding the biosensor is minimized. A need also exists to achieve a rough exterior of the portion of an implantable biosensor exposed to surrounding tissue so that foreign body reaction may be reduced. Similarly, there is a need for a selected membrane or membrane combination suitable to correction of nonlinear diffusion of glucose. Further needed is a method of manufacturing such a miniaturized yet strong and durable implantable biosensor with resilient flexibility and minimal surface relief while achieving a microscopically porous surface.
BRIEF SUMMARY OF THE INVENTION
[0013] The invention includes an implantable needle-type biosensor wherein an electric signal is produced between first and second electrical contacts responsive to an electrochemical reaction in a body. A needle-like probe element is typically inserted through an introducer cannula into tissues of a subject's body. An implantable needle element of an exemplary biosensor includes an elongate core having a distal end spaced apart axially from a proximal end. A workable core may be formed as a single element, or may include a plurality of axially oriented fibers arranged in a bundle. Certain cores are nonconductive to electric current. Workable cores may be made from natural and synthetic fibers, metal, polymers, and plastics. Currently preferred cores are made from polymer material.
[0014] In general, a working electrode is associated with a distal end of the core. Desirably, the working electrode is arranged to protrude beyond a distal end of an introducer cannula into intimate contact with tissue of a subject's body. A reference electrode is included in abiosensor to produce an electrical signal, in combination with the working electrode, responsive to the electrochemical reaction. Structure included in a biosensor is adapted to resist direct physical contact between the working electrode and the reference electrode to prevent forming a direct electrical short between those electrodes.
[0015] A first electrically conductive path exists between the working electrode and a first electrical contact. Similarly, a second electrically conductive path exists between the reference electrode and a second electrical contact. The first and second electrical contacts typically are associated with a hub operable to secure a probe in relation to a cannula. A signal may be received from the first and second contacts for data reduction and correlation to a physiological state in a body, such as glucose concentration. In general, the signal is transmitted through a sensor cable affixed to structure of the hub. A workable sensor cable includes first and second wires, each wire having a first end arranged to make respective electrical connections with one of the first and second electrical contacts, and a second end of each wire typically being affixed to a sensor module operable to impose a conditioning signal on the biosensor probe.
[0016] A working electrode can include a metal element (usually including platinum) formed as a wrap about a portion of the core. An exemplary working electrode includes a length of a first wire arranged to circumscribe a plurality of revolutions about the core. In such an exemplary working electrode, a diameter of the first wire is between about 0.001 and about 0.005 inch. Desirably, the first wire is arranged to form a spiral path. Usually, at least a portion of the core is disposed substantially coaxial with an axis of the spiral path. A currently preferred spiral path has an axial spacing, between the centerlines of a pair of adjacent wire wraps, sized between about one and about two diameters of the first wire. A larger spacing, up to about five diameters (or even more in some cases), is also workable, although it is recognized that the electrode's active surface area decreases with larger pitch spacing. Typically, the working electrode is arranged to reinforce the core so as to enable a reinforced core to carry an axial compression load permitting insertion of a distal tip of the biosensor through an introducer catheter for placement of the working electrode into intimate contact with tissue of the subject's body.
[0017] The reference electrode typically includes a metal element (usually including silver, and preferably including chlorided silver) and can also be associated with the distal end of a core. A reference electrode may alternatively be associated with an introducer cannula, or some other structure. In the latter case, a reference electrode may sometimes be recessed into an exterior surface of the introducer cannula. In any event, it is currently preferred for a reference electrode to be placed into intimate contact with tissue of a subject's body. One embodiment of a reference electrode includes a length of a second wire formed as a wrap about a portion of the core. Another embodiment of a reference electrode may be fashioned as a length of wire, wire coil, foil, film, or coating associated with a cannula.
[0018] A preferred electrode (either working or reference) maybe characterized as having: an axially interrupted load path between first and second ends, a maximum equivalent outside diameter, a minimum equivalent inside diameter, and a surface texture disposed between the first and second ends that has a radially oriented component. Such an electrode has a larger reactive surface area and a lower bending stiffness compared to a hollow cylinder structured from an equivalent material and having equivalent maximum outside and minimum inside diameters.
[0019] The core of a biosensor probe according to the instant invention can function to assist in retraction of the various components of the biosensor probe. One structure operable to assist in such retraction includes a plug carried on a distal end of the core. The plug can be structured as a stopper that is too large to pass through an electrode. Such a stopper operates to resist extraction of the core from within a portion of the working electrode as the biosensor is removed from the subject's body, so as not to leave a detached portion of the working electrode in the body. One functional plug is preferably formed, at least in part, with a polymer coating. Another functional plug can include a droplet of dielectric adhesive. A functional plug typically forms an enlargement in a cross-section of the core, with a portion of the enlargement being disposed distal to the working electrode.
[0020] In probes carrying both working and reference electrodes, a dielectric spacer is usually interposed between the electrodes to resist direct physical contact between them. A functional dielectric spacer can be made from a droplet of dielectric adhesive bonded to a portion of the core. Such a droplet desirably also is arranged as a stopper to resist extraction of the core from within a portion of the reference electrode as a biosensor is removed from a subject's body, so as not to leave a detached portion of the reference electrode in the body.
[0021] A probe portion of a biosensor includes a sensor shaft disposed between the working electrode and the hub. The sensor shaft generally includes a cylinder disposed circumferentially about an axial length of the core proximal to the working electrode. A currently preferred cylinder includes a plurality of circumferential wrappings of a component wire having a smaller diameter than a diameter of the formed cylinder. Wrappings forming the cylinder desirably are closely spaced, or even touching, in an axial direction along an axis of the cylinder whereby to enable the shaft to carry an axial compression load effective to install the biosensor probe portion through an introducer cannula and into a body. Usually, a dielectric spacer is disposed at a distal end of the cylinder to resist direct physical contact between the shaft and an electrode. One such dielectric spacer can be formed from a droplet, or small quantity, of dielectric adhesive bonded to a portion of the core.
[0022] Desirably, an exterior coating of a negatively charged polymer is applied to the working electrode. One operable negatively charged polymer includes sulfonated polyethersulfone. It is also sometimes desirable to provide a microscopically roughed-up outer surface on the coating to enhance biocompatibility of the biosensor with tissue of the subject's body. Desirable surface texture is formed by elements having a size of between about 5 and 50 microns. Multifiber cores typically include a plurality of spaces between the fibers operable to carry glucose oxidase whereby to enhance a volume of glucose oxidase associated with a working electrode.
[0023] The instant invention may be embodied broadly as an implantable biosensor including an introducer cannula and a probe element. The introducer cannula includes a lumen extending axially between its proximal and distal ends. The cannula's proximal end carries affixing structure adapted to resist motion of the proximal end relative to a skin surface of a subject and further carries holding structure configured to receive a probe. A distal end of the cannula carries a first electrode. A probe includes an elongate core having a distal end spaced apart axially from a proximal end and is structured for sliding installation, through the cannula lumen, into a subject. A proximal end of the probe is associated with a hub adapted to be held by the cannula-holding structure. The distal end of the probe carries a second electrode. The probe and cannula are cooperatively structured on assembly to resist direct physical contact between the first electrode and the second electrode. Desirably, the first and second electrodes are installed to be in intimate contact with the tissue of a subject.
[0024] A method for manufacturing an implantable, needle-type biosensor probe with a transversely flexible first electrode effective to resist irritation at a site of implantation in a subject includes the steps of: a) providing a core comprising a first nonconductive material; b) disposing a first electrode in a reinforcing path about the core; c) disposing a first electrical conductor between the first electrode and a hub associated with a proximal end of the probe; and d) disposing a second electrical conductor between a second electrode and the hub. The method can also include the step of: e) forming a stopper carried by the core, a portion of the stopper being disposed distal to the first electrode and operable to resist extraction of the core from within the interior of the electrode, whereby to retain an association between the core and the electrode to resist leaving a portion of the electrode in a subject subsequent to removal of the probe.
[0025] Sometimes, step b) includes: forming the first electrode as an axially interrupted first cylinder having a first length between a first end and a second end, a maximum equivalent outside diameter, and a minimum equivalent inside diameter. The first cylinder desirably includes a surface texture disposed between its first and second ends that has a radially oriented component so as to provide a larger reactive surface area and a lower bending stiffness than a second cylinder having an equivalent maximum outside diameter and first length. An exemplary electrode having such conformation can be formed from a wire of between about 0.001 and about 0.005 inch in diameter, with the wire being disposed to occupy a spiral path about the core.
[0026] In some cases, the method may further include disposing a second wire circumferentially about the core in a spiral reinforcing path operable to enhance an axial load-carrying capability of the core, whereby to form the second electrode. Typically, the step of applying an insulation to a conductive path extending proximally from one or both electrodes is further included. When two electrodes are carried on a core, the method additionally can include affixing a dielectric element between the working and the reference electrodes. Such dielectric element desirably is also adapted to resist extraction of the core from retention in an electrode, whereby to resist leaving a portion of that electrode inside a subject subsequent to extraction of the probe. Generally, the method includes the step of wrapping, or otherwise disposing, a third wire circumferentially about the core in a spiral reinforcing path to form a shaft of the probe. Furthermore, the method includes affixing the hub to a proximal portion of the shaft.
[0027] Coatings are typically applied in additional steps subsequent to assembly of basic probe structure. An inner exclusion membrane is formed in a first coating step by applying a solution, such as 5% polyethersulfone, to the working electrode. A second coating step includes applying a solution, such as 1% glucose oxidase, 0.6% albumin and 0.5% glutaraldehyde, to the working electrode to form a middle enzymatic membrane. In a third coating step, a solution, such as 5% polyurethane is applied to both the working and the reference electrodes to form an outer polymer membrane. The final polyurethane coating desirably is microscopically roughed-up by performing a phase inversion polymerization procedure. In general, a workable phase inversion polymerization procedure includes immediately dipping the final polyurethane layer into a water bath to largely rinse away the miscible solvent soon after the first of the polymer molecules comprising the 5% solution have begun to bond with the second-to-last layer. Desirably, the resulting surface includes protruding particles sized between about 5 and 50 microns.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0028] In the drawings, which illustrate what are currently regarded as the best modes for carrying out the invention:
[0029] FIG. 1 is a schematic of one configuration of a preferred embodiment;
[0030] FIG. 2A is a perspective side view in elevation of a first implantable biosensor according to the present invention;
[0031] FIG. 2B is an enlarged perspective view in elevation of a probe portion of the implantable biosensor illustrated in FIG. 2A ;
[0032] FIG. 2C is a perspective side view in elevation of the implantable biosensor of FIG. 2A , in a partially assembled configuration;
[0033] FIG. 2D is a perspective side view in elevation of the implantable biosensor of FIG. 2A , in an assembled configuration;
[0034] FIG. 3 is a side view illustrating a stage of construction of a probe portion of the implantable biosensor of the invention;
[0035] FIG. 4 is a side view of an assembled but uncoated miniature probe portion of the biosensor of the invention;
[0036] FIG. 5 is an enlarged cross-sectional side view of a miniature, flexible probe portion of the implantable biosensor;
[0037] FIG. 6A is a perspective side view in elevation of a second implantable biosensor according to the present invention;
[0038] FIG. 6B is an enlarged perspective view in elevation with greater resolution of a portion of the embodiment illustrated in FIG. 6A ;
[0039] FIG. 6C is a perspective view in elevation of the embodiment of FIG. 6A in a partially assembled configuration; and
[0040] FIG. 6D is a perspective view in elevation of the embodiment of FIG. 6A in an assembled configuration.
DETAILED DESCRIPTION OF THE INVENTION
[0041] FIG. 1 illustrates a preferred embodiment in which an implantable biosensor, generally 10 , and associated sensor cable 20 are provided. Miniaturized and highly flexible, the biosensor 10 may be placed into a subject subcutaneously through a cannula such as an introducer catheter 30 . The biosensor 10 as illustrated is associated percutaneously through the sensor cable 20 with a sensor module 40 , which in turn is associated via a module cable 50 with a Sensor Display Unit (“SDU”) 60 . The SDU 60 can be structured to be interactive across SDU cable 70 with computer hardware and other software, generally 80 .
[0042] The foregoing biosensor system may include a single-use portion and a reusable portion. The single-use portion includes the introducer catheter 30 , the biosensor 10 , the sensor cable 20 , the sensor module 40 and the module cable 50 . The introducer catheter 30 can generally be regarded as a separate component, although certain embodiments may incorporate the catheter to carry a portion of a biosensor probe. The biosensor 10 , sensor cable 20 , sensor module 40 and module cable 50 desirably are all permanently affixed to each other. Module cable 50 typically is removably attached at disconnect 55 to SDU 60 . The SDU 60 and SDU cable 70 may be reused. When attached to the SDU 60 , the SDU cable 70 allows the glucose information to be downloaded to a personal computer 80 that is loaded with the sensor download software.
[0043] To install a preferred embodiment of a biosensor 10 , introducer catheter 30 can be inserted into the subcutaneous tissue of a subject on a supporting needle (not illustrated). The supporting needle is removed to leave an opening through the cannula and, typically, a short path extension into the subject's tissue. Then, the biosensor 10 maybe placed into the introducer catheter 30 such that a portion of the biosensor 10 protrudes beyond the introducer catheter 30 . The working electrode 100 and reference electrode 110 of the presently preferred embodiment are designed to be deployed 3-10 mm into the subcutaneous fatty tissue of a subject to monitor glucose concentration in the interstitial fluids. The introducer catheter 30 /biosensor 10 assembly, as well as the sensor module 40 , is then generally affixed to the skin (not shown) via an adhesive patch.
[0044] The biosensor 10 produces a small electrical current that is proportional to the glucose concentration. This current is amplified and conditioned by the sensor module 40 . The sensor module 40 also provides a polarization voltage to the working electrode of the biosensor 10 . The amplified signal typically is interpreted by the SDU 60 , which generally calibrates, displays and stores the glucose data.
[0045] The biosensor 10 , as set forth in FIGS. 2A-2D , includes a sensor shaft 90 with sensor cable 20 extending therefrom, a working electrode 100 , a reference electrode 110 and a hub 120 for attaching the biosensor 10 to the introducer catheter 30 . With reference to FIG. 2B , the working electrode 100 and reference electrode 110 are adjacent a first dielectric spacer 130 . The reference electrode 110 and sensor shaft 90 are adjacent a second dielectric spacer 140 . A filament core 150 is visible in FIG. 2B through a polymer cap 160 . The dielectric spacers 130 , 140 provide one arrangement of structure operable to prevent the two electrodes from shorting together through a direct physical contact between the electrodes.
[0046] The filament core 150 may include any of a variety of suitable materials, such as polymeric, ceramic, or flexible metallic materials, that can sometimes be insulated. One currently preferred filament core 150 , as illustrated in FIG. 3 at an intermediate stage of construction of a biosensor 10 , includes a plurality of filamentous fibers 170 of a polymeric material bundled in substantially axial alignment with respect to each other. Fibers 170 forming an exemplary filament core 150 may be formed from natural or synthetic fibers, and may have round, rectangular, uniform, or even irregular cross-sections. A desirable core material will have sufficient tensile strength to aid in extraction of biosensor elements entrained thereon.
[0047] A desirable flexible filament core 150 forms a biosensor 10 having enhanced transverse flexibility operable to reduce irritation at the installation location in a subject compared to rigid needle-type biosensors. A filament core 150 desirably is structured and arranged in a multistrand configuration to increase transverse flexibility of biosensor 10 . A multistrand core provides a plurality of strands, each strand having a significantly reduced cross-section and bending stiffness compared to a solid cross-section replaced by that core. A plurality of such strands 170 in combination can form a transversely flexible biosensor 10 . For the purpose of this disclosure, a solid copper needle having a diameter of about 25 gauge is regarded as being transversely rigid.
[0048] With reference to FIGS. 3 and 4 , working wire lead 180 provides structure that forms a conductive path that extends from the working electrode 100 for electric communication through the sensor cable 20 (see, FIG. 1 ). The conductive path can be disposed among the fibers 170 and extends axially along the sensor shaft 90 . The working electrode 100 of biosensor 10 is typically formed of platinum, or a platinum compound, and desirably circumscribes the filament core 150 in the form of continuous working coils, generally 190 . One operable conductive path is formed by a proximally directed axial extension of a wire formed at its distal end into working electrode 100 .
[0049] The reference electrode 110 in FIG. 4 preferably is formed from a chlorided silver substrate. A reference electrode 110 typically extends axially along a portion of the filament core 150 and desirably circumscribes the filament core 150 in the form of continuous reference coils, generally 200 . A reference wire lead 210 forms a conductive path that extends from the coils 200 of reference electrode 110 for electric communication through the sensor cable 20 . An exemplary conductive path can be formed from a proximally extending portion of reference wire lead 210 forming the reference electrode 110 . The conductive path can be insulated and/or disposed among the fibers 170 . Both the working wire lead 180 and the reference wire lead 210 are typically available for termination to a distal end of the sensor cable 20 at a hub 120 . An extension to leads 180 and 210 may effectively continue from electrical contacts, generally located in association with the hub, to extend along sensor cable 20 and provide electrical contacts at a proximal end of sensor cable 20 .
[0050] The sensor shaft 90 , in certain embodiments, is formed as a cylinder about the filament core 150 . One workable cylinder may, at least in part, be formed of small-diameter stainless steel wire. A sensor shaft 90 may be arranged, as illustrated, to circumferentially circumscribe the filament core 150 in the form of continuous body coils, generally 220 . Generally, wire used to form coils 190 , 200 , and 220 has a diameter between about 0.001 and 0.005 inch, with about 0.002 inch being currently preferred. The configuration of coils 190 , 200 , and 220 desirably lends additional axial compressive load-carrying capability to the fibers 170 of the biosensor 10 while maintaining the lateral flexibility of the highly flexible, sometimes even flaccid, fibers 170 , thereby reducing a tendency toward scarring in surrounding tissue when implanted.
[0051] While the illustrations generally depict electrodes and sensor shafts that are substantially cylindrical, such is not a strict requirement. For instance, a workable core can be formed having a triangular, square, rectangular, or even other alternatively shaped cross-section. An electrode or shaft reinforcement can be wound around such core to form a tube with a cross-section substantially conforming to that of the core. In another example, a reinforcing electrode can be applied to a core having such a noncircular cross-section by way of a coating, printing, vapor deposition, or other procedure to form a tubular electrode that may be characterized as providing some “effective” inner and outer diameters. Furthermore, in some cases, a shaft reinforcement can be formed from a shrink-fit tubing that substantially conforms to an underlying core profile.
[0052] The coils 190 , 200 , and 220 may be relatively less closely wound (with respect to an axial spacing, or pitch, between centerlines of adjacent coils) about the fibers 170 in certain configurations other than embodiments illustrated in this disclosure. However, an increase in the relative closeness of the coils 190 and 200 results in an increase in reactive surface area for the respective electrodes 100 , 110 , thus enhancing sensitivity and accuracy of readings obtained from a biosensor 10 . Adjacent coils 220 can be placed abutting one another (with an axial spacing, or pitch, between centerlines of adjacent coils of one coil-wire diameter) to maximize axial load-carrying capabilities of a sensor shaft 90 , while still retaining a significant increase in transverse flexibility, compared to a rigid solid shaft.
[0053] Construction of a biosensor 10 , including coils 190 , 200 , 220 as illustrated, generally enhances the sensor's flexibility and resistance to damage. Transverse flexibility is greatly increased over a comparable solid cross-section because the load path is changed. Both a solid shaft and a cylinder have a cross-section that carries a bending-induced load along an uninterrupted, axially directed load path as axial tension and axial compression stress. Coils provide an axially interrupted load path along a length of the electrode (or sensor shaft 90 ). Coil structures cannot carry bending loads in the same way an uninterrupted surface can. Under transverse bending of an illustrated biosensor 10 , the coils displace in a shear mode and carry loads as torsion and bending loading in the coil elements, but the bending load path and effective displacements are entirely different than those in a solid shaft. For example, the bending of a coil element is essentially orthogonal to the bending in the equivalent uninterrupted surface. The stress induced in the coil element is, therefore, significantly lower (potentially by orders of magnitude) than the stress induced in the comparable solid cross-section. A coil arrangement therefore resists breaking-off of electrode portions inside a subject and reduces irritation at the implantation interface.
[0054] An axially interrupted electrode can be formed other than as a coil structure. For example, a cylinder can be made to provide circumferential relief, or radially directed cuts, in an overlapping finger pattern. Such relief can be laser etched from a continuous cylinder. Alternatively, such pattern can be printed or etched. The relief also provides a radial component to the electrode surface, thereby potentially increasing the available reactive surface area of the electrode.
[0055] Filament core 150 and its associated cap 160 work in harmony to further resist leaving any broken-off portions of electrode, such as working electrode 100 , behind in a subject when a biosensor 10 is removed from the subject's tissue. Cap 160 desirably is operable as a stopper forming an interference to resist extraction of filament core 150 from within an electrode. That is, the stopper functions to hold an electrode (such as working electrode 100 ) at a distal tip end 310 ( FIG. 5 ), placing the working electrode 100 into compression during withdrawal of a biosensor 10 . A cap 160 desirably provides structure sized larger than an inside diameter of an electrode. Therefore, the cap 160 forms an interference with the electrode to resist separation of the electrode from the filament core 150 . Certain embodiments of cap 160 may adhere an electrode, or a portion of an electrode, directly to a filament core 150 . It is within contemplation for a cap 160 to be formed by melting a distal portion of a filament core 150 . The filament core 150 desirably provides a strand of material having sufficient tensile strength to overcome resistance due to adhesion between body tissue and portions of a biosensor 10 . Therefore, filament core 150 and cap 160 are relied upon for extraction of the biosensor 10 .
[0056] The electrodes 100 and 110 of the biosensor 10 , in a preferred embodiment, are illustrated in an enlarged view in FIG. 5 to illustrate three layers of membranes. An inner exclusion membrane 230 is depicted as surrounding and being adjacent to the working electrode 100 . The inner exclusion membrane 230 , preferably formed of polysulfone or sulfonated polyethersulfone, serves to reduce the sensor artifact that is caused by non-endogenous electroactive molecules, thus excluding interfering compounds such as ascorbic acid and acetaminophen. A middle enzymatic membrane 240 surrounds the inner exclusion membrane 230 . The middle enzymatic membrane 240 includes immobilized glucose oxidase enzyme that converts glucose to hydrogen peroxide to generate a current. An outer polymer membrane 250 surrounds the middle enzymatic membrane 240 , as well as the reference electrode 110 , to restrict diffusion of glucose while allowing the free passage of oxygen. This outer polymer membrane 250 may be formed of various polymers. One preferred embodiment of an outer polymer membrane 250 is formed of polyurethane. A careful approach to material selection for the membrane layers 230 , 240 , and 250 facilitates correction of the nonlinear diffusion of glucose and reduces errors resulting from interfering electroactive species.
[0057] It can be appreciated that the introducer catheter 30 , typically used in conjunction with a preferred embodiment biosensor 10 , provides access from outside the body (not shown) to the tissue just under the skin layer (not shown). With reference to FIG. 2A , the biosensor 10 is inserted into and through a lumen 260 of the introducer catheter 30 to a point at which the polymer cap 160 , working electrode 100 and reference electrode 110 of the biosensor 10 protrude beyond and outside the introducer catheter lumen 260 . Such placement allows the working electrode 100 and reference electrode 110 to be in communication with the surrounding tissue (not illustrated).
[0058] With reference to FIGS. 2B and 5 , polymer cap 160 , located at a head portion 270 of the biosensor 10 , provides a conformal material that coats the fibers 170 extending beyond the working electrode 100 and adheres the fibers 170 into the unified filament cap 160 . The working electrode 100 , as illustrated, extends along a leading portion, generally 280 , of the biosensor 10 . As further illustrated, the reference electrode 110 extends along the trailing portion 290 . The leading portion 280 and trailing portion 290 , as best illustrated in FIG. 2D , extend beyond the lumen 260 of the introducer catheter 30 when introduced into a subject. The sensor shaft 90 may include a tail portion 300 along which the body coils 220 may be located (see, FIG. 4 ).
[0059] As illustrated in FIG. 5 , working electrode 100 includes a distal tip end, generally 310 , and a proximal tip end, generally 320 . The distal tip end 310 , as illustrated, is associated with the filament core 150 at or near the head portion 270 . The proximal tip end 320 is associated with the filament core 150 at or near the trailing portion 290 or tail portion 300 depending upon the configuration. In one configuration, a reference electrode 110 is separate from a needle-probe portion of a biosensor. In another configuration and as illustrated in FIG. 5 , a reference electrode 110 is included on the biosensor 10 probe.
[0060] The preferred embodiment 10 illustrates the working electrode 100 as being structured in the form of coils. However, it is only necessary that the working electrode 100 be in length substantially not less than the leading portion 280 when the leading portion 280 is laterally deflected to a maximum extent. Such a limitation is operable to resist separation of an electrically conductive path from the electrode due to bending of the biosensor. Correspondingly, whereas in a preferred embodiment the reference electrode 110 is illustrated as being in the form of coils, in essence a working electrode 110 may be in length substantially not less than the trailing portion 290 when the trailing portion 290 is laterally deflected to a maximum extent.
[0061] FIGS. 6A-6D illustrate an alternative preferred embodiment of a biosensor, generally indicated at 330 , including an introducer catheter, generally indicated at 340 . The biosensor 330 includes a working electrode, generally 350 , typically corresponding in function, materials, location and other general characteristics with the working electrode 100 . The biosensor 330 further includes a polymer cap 360 , filament core 370 , working coils 380 , dielectric spacer 390 , head portion, generally 400 , leading portion 410 , tail portion 420 , hub 430 , working electrode lead 440 , and body coils 445 . Biosensor 330 generally includes membranes and is structured to provide characteristics and features that in turn generally correspond to those of the biosensor embodiment 10 .
[0062] The introducer catheter 340 , like the introducer catheter 30 , includes a lumen that may be thought of as an interior cannula lumen 450 . Furthermore, the illustrated introducer catheter 340 presents an advanced end 460 designed for subcutaneous or other intra-tissue placement, an opposite end, generally 470 , and a cannula wall 480 defining the interior cannula lumen 450 and comprising an exterior surface 490 . The exterior surface 490 and the interior cannula lumen 450 extend between the advanced end 460 and the opposite end 470 . In the biosensor embodiment 330 , a reference electrode 500 is associated with the exterior surface 490 of catheter 340 in the vicinity of the advanced end 460 . Electrode 500 may take other forms, such as a film, band, etching, printed or imprinted layer, or a shell or coating. The interior cannula lumen 450 is of sufficient cross-sectional diameter to pass the biosensor 330 . The advanced end 460 and exterior surface 490 of the introducer catheter 340 are structured and arranged to enable access of the advanced end 460 into and through subcutaneous or other subject tissue.
[0063] The opposite end 470 generally includes one or more surfaces 510 useful for adhesively fixing the introducer catheter 340 to the skin. The hub 430 may be anchored to the opposite end 470 of the introducer catheter 340 . The opposite end 470 may be further structured and arranged to engage the hub 430 , upon advancement of the biosensor 330 through the interior cannula lumen 450 sufficiently far, so that the alternative working electrode 350 reaches a position extending beyond the advanced end 460 . Upon achievement of such a position, a reference wire lead 520 associated with the hub 430 may be brought into register with the reference electrode 500 carried by the catheter 340 .
[0064] Glucose (“Glu”), in a somewhat restricted manner, and Oxygen (“O 2 ”), comparatively freely, diffuse from the interstitial tissues of the subject through the outer polymer membrane 250 (see FIG. 5 ) and, in the presence of the glucose oxidase (“GO x ”) of the middle enzymatic membrane 240 , produce gluconic acid “GluA”) and hydrogen peroxide (“H 2 O 2 ”). The H 2 O 2 , upon interaction with the platinum (“Pt”) working electrode 100 , which is typically polarized at approximately 0.7 volts, creates a current which travels up the working wire lead 180 for processing through the sensor module 40 . A differential signal is generally measured between the working electrode 100 and the reference electrode 110 at the sensor module 40 , and successively transmitted to the SDU 60 and ultimately the computer 80 .
[0065] In the manufacture of a biosensor 10 , a plurality of filamentous fibers 170 of the filament core 150 are axially aligned in a bundle and bonded to form the polymer cap 160 . The wire material of a working electrode 100 can be manually or mechanically wrapped around the filament core 150 beginning at the head portion 270 and continuing proximally across the leading portion 280 to form the working coils 190 (see FIGS. 4 and 5 ). An exemplary working electrode 100 is somewhat cylindrical, about 0.60 inch in axial length and about 0.015 inch in maximum outside diameter. It is currently preferred to form an electrode, such as a working electrode 100 , from a wire wound on a spiral path.
[0066] If the biosensor includes a reference electrode 110 adjacent to, but apart from, the working electrode 100 , the reference electrode 110 can likewise be manually or mechanically wrapped around the filament core 150 and working wire lead 180 . Reference electrode 110 is structured to occupy a desired axial distance and desirably forms reference coils 200 electrically communicating with the reference wire lead 210 . Reference wire lead 210 and the working wire lead 180 extend proximally among the fibers 170 . Body coils 220 are then similarly wrapped around the filament core 150 and leads 180 and 210 , terminating at a proximal end, generally indicated at 305 ( FIG. 4 ).
[0067] A core may also be threaded through preformed electrodes and dielectric spacers. Certain preferred polymer cores can be heated and drawn slightly at a distal portion to form an operable needle to assist in threading the electrodes. In embodiments manufactured by threading one or more premanufactured electrodes, a conductive path from the respective electrode(s) is generally insulated prior to the threading assembly step. The conductive path typically includes a proximally protruding portion of the wire forming a coiled electrode. Such proximally directed wire desirably is disposed among strands of a core for additional insulation.
[0068] The working electrode 100 is next manually or mechanically dipped in a vertical orientation into at least one coating of 5% polyethersulfone in the solvent DMAC to form the inner exclusion membrane 230 and dried to ensure solidification of the coating. Of course, while reference is made in this disclosure to dipping, it is to be realized that other procedures operable to apply a coating (e.g., brushing, spraying, vapor deposition, and the like) are intended to be encompassed by such language. Successive coatings may be desirable and accomplished by repeating the application process.
[0069] The working electrode 100 and filament core 150 are then manually or mechanically dipped in a vertical orientation into at least one coating of 1% glucose oxidase, 0.6% albumin and 0.5% gluteraldehyde in water to form the middle enzymatic membrane 240 , and dried to ensure solidification ofthe coating. As with the inner exclusion membrane 230 , successive coatings may be desirable and accomplished by repeating the foregoing process. In certain embodiments, the electrode is assembled onto a filament core 150 before the step of applying glucose oxidase. In that case, the glucose oxidase can fill in any spaces between the core fibers 170 to increase the volume of glucose oxidase associated with the electrode. The increased volume of glucose oxidase provides enhanced sensor stability and shelf life.
[0070] Next, in biosensor configurations such as embodiment 10 , having the working electrode 100 and reference electrode 110 positioned adjacent but separate from each other on the filament core 150 , both the working and reference electrodes 100 and 110 are manually or mechanically dipped in a vertical orientation into at least one coating of 5% polyurethane in the solvent tetrahydrofuran to form the outer polymer membrane 250 , and dried to ensure solidification of the coating. Again, successive coatings may be desirable and accomplished by repeating the foregoing process. Successive coatings contemplate use of an approximately 5% solution in a solvent such as, for example, tetrahydrofuran or methylene chloride, to allow for solvent drying from liquid to gel to jelly to a tightly bound conformal coating. The coating materials and respective number of layers are selected to balance response time, electrical insulation, biocompatibility and diffusive properties. For example, a thicker layer increases response time but provides better insulation. To enhance biocompatibility, the outermost surface of the final layer can be made microscopically rough by phase inversion polymerization, i. e., by immediately dipping the last layer in water to allow the miscible solvent to be largely rinsed away soon after the first of the fibers comprising the 5% solution have begun to bond with the second to last layer. Such a procedure typically results in a surface including projecting particles that are sized between about 5 and 50 microns.
[0071] If the biosensor is structured to include coterminous wrapping of both the working and reference electrodes 100 , 110 , then the sequence of the foregoing method of manufacturing would be altered by, prior to coiling, applying the inner exclusion membrane 230 , the middle enzymatic membrane 240 and a preliminary outer polymer membrane 250 coating to the portion of the working electrode 100 to be coiled, then coiling both the coated working electrode 100 and the reference electrode 110 over a portion of the filament core 150 comparable in length to both working and reference coils 190 , 200 when adjacent but separate, and finally coating both coterminous coiled electrodes 100 , 110 as desired.
[0072] The system, apparatus and method of the present invention provide distinct advantages over prior implantable biosensors. Thus, reference herein to specific details of the illustrated or other preferred embodiments is by way of example and not intended to limit the scope of the appended claims. It will be apparent to those skilled in the art that modifications of the basic illustrated embodiments may be made without departing from the spirit and scope of the invention as recited by the claims.
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An implantable biosensor assembly and system includes an enzymatic sensor probe from which subcutaneous and interstitial glucose levels may be inferred. The assembly may be associated by direct percutaneous connection with electronics, such as for signal amplification, sensor polarization, and data download, manipulation, display, and storage. The biosensor comprises a miniature probe characterized by lateral flexibility and tensile strength and has a large electrode surface area for increased sensitivity. Irritation of tissues surrounding the probe is minimized due to ease of flexibility and small cross section of the sensor. Foreign body reaction is diminished due to a microscopically rough porous probe surface.
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TECHNICAL FIELD
The present invention relates to integrated circuit design methodologies and, in particular, to the basic design of a hierarchical device level digital simulator that utilizes the native module hierarchy of a digital circuit for efficient simulation.
DISCUSSION OF THE RELATED ART
Software programs for use in simulating integrated circuit design and predicting the operational behavior of the circuit are well known to those skilled in the art.
SUMMARY OF THE INVENTION
FIG. 1 shows a well-known general architecture of a data processing system 100 that can be utilized to execute a program implementation of a digital integrated circuit simulator. The data processing system 100 includes a central processing unit (CPU) 102 and a system memory 104 that is connected to the CPU 102 . The system memory 104 typically stores the operating system for the CPU 102 as well as data and various sets of program instructions for applications programs to be executed by the system 100 . For example, the system memory 104 could store a software program, i.e. a sequence of machine readable program instructions, needed to implement a method for using state nodes for the efficient simulation of digital integrated circuits at the transistor level in accordance with the concepts of the present invention. Typically, the computer system 100 also includes a display 106 that is connected to the CPU 102 to allow images to be visually displayed to a user, a user input system 108 , e.g., a keyboard or mouse, that allows the user to interact with the system 100 , and a memory access system 110 that enables transfer of data both within the system 100 and between the system 100 and systems external to the system 100 , e.g. a computer network to which the system 100 is connected. All of these components and the ways in which they interact are well known to persons skilled in the art.
Conventional device level digital integrated circuit simulators, such as the well-known public domain tool IRSIM, supported by the University of California—Berkeley, work on “flat” circuits, that is, circuits that have no module hierarchy. Thus, a hierarchical circuit must be flattened to transistor level before it will work on these conventional simulators. This approach has a major drawback. Most digital circuits, whether custom designed (e.g., memories) or standard cell based (e.g., ASICs), make extensive re-use of the same building blocks or lower level modules. For example, the major portion of a static random access memory (SRAM) circuit is made up of multiple repetitions of the same six-transistor memory core cell. A flattened netlist for the SRAM design does not reflect this fact. Simulations of identical circuit modules are repeated for each occurrence of the module in the circuit, resulting in a relatively time-consuming operation.
A simulation method in accordance with the present invention takes advantage of the fact that, when an instance of a circuit module has been simulated under a given set of input conditions, and the resulting output values and delays have been evaluated, another instance of the same module need not be re-simulated when it has the same input combination as the prior module instance; the results computed earlier for the earlier module instance can be re-used for the current instance.
The features and advantages of the various aspects of the present invention will be more fully understood and appreciated upon consideration of the following detailed description of the invention and the accompanying drawings, which set forth illustrative embodiments in which the concepts of the invention are utilized.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram illustrating a conventional data processing system.
FIG. 2 is a flow chart illustrating a method of simulating combinatorial logic modules in accordance with the concepts of the present invention.
FIG. 3 is a flow chart illustrating a method of distinguishing between combinatorial logic circuit modules and sequential circuit modules.
FIG. 4 is a flow chart illustrating a method of simulating sequential circuit modules I accordance with the concepts of the present invention.
FIG. 5 is a schematic drawing illustrating an embodiment of a conventional circuit containing transient state points.
FIG. 6 is a flow chart illustrating a method of constructing a graph from a circuit netlist.
FIG. 7 is a graph representation of the FIG. 5 circuit created in accordance with the FIG. 6 flow chart.
FIG. 8 is a flow chart illustrating a method of indentifying transient state nodes from the graph representation of the circuit.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 2 shows a flow chart of a method of simulating combinatorial logic modules in accordance with the concepts of the present invention. As shown in FIG. 2 , for a module A in the hierarchy of an integrated circuit design, a look-up table is maintained that stores the input-output combinations encountered for any instance of module A. When an instance of module A needs re-simulation (i.e., one or more of its inputs change value), the look-up table is checked to determine if the current input values have been encountered in an earlier simulation of module A. If they have, then the output and delay values stored in the look-up table are used and a complete re-simulation of this instance of module A is avoided. This drastically reduces the simulation time. When the current input values for that instance of module A are not present in the look-up table, then a simulation is performed and the output and delay results for that instance of module A are stored in the look-up table and can be used in future re-simulations of any other instance of module A.
The method described above works for purely combinatorial modules, since the output values and delays of a combinatorial module are governed solely by its inputs. However, for sequential modules, the output conditions of the module depend not only upon the inputs, but also upon the present state of the module. Thus, for sequential circuits, not only the input-output combinations, but also the states must be stored. For each instance of a module in the sequential circuit, its present state must be stored in the look-up table. During a simulation, the output combinations of that instance of the module are determined based upon the input values and the present state. After the simulation, the state of the module instance is updated to the next state. As is well known, this relation can be expressed as:
( O,NS )= f ( I,PS ) (1)
where, O is the output vector, NS is the next state, I is the input vector, PS is the present state, and f is a Boolean function.
The problem is how to define what is meant by a “state” of a sequential module. One obvious (recursive) definition is as follows. The state of a module is defined by: (1) the state (logic value) of all of the internal nodes in the circuit; and (2) the state of all sub-modules of this module. However, this “obvious” definition has two major problems. First, storing the value of all of the internal nodes in a module for all instances of that module has a huge memory overhead and a look-up table search time penalty. Second, some (or all) of the sub-modules of a module may be combinatorial in nature, making it is unnecessary to store their states.
The present invention makes use of “state nodes” to circumvent the above-described problem. Intuitively, a state node is a node that can retain its logic value even in the absence of an input directly driving this node. In accordance with the invention, a circuit module is termed sequential if either of the following conditions holds true: (1) the module has state nodes or (2) the module has one or more sequential sub-modules.
The “state” of a sequential module is defined as follows. The state consists of: (1) the state (logic value) of all state nodes of the module and (2) the state of all sequential sub-modules of the module. Since the number of state nodes in a circuit is much less than the number of internal nodes, this definition of a module state is much more efficient in terms of both space as well as lookup time than the earlier definition.
The FIG. 3 flow chart summarizes the process of distinguishing between combinatorial modules and sequential modules. As shown in the FIG. 3 flow, if a module A has any state nodes, then it is defined as a sequential module. If the module A has no state nodes, but includes sequential submodules, then it is defined as a sequential module. If module A has neither state nodes nor sequential submodules, then it is defined a combinatorial module and may be simulated as such in accordance with the FIG. 2 flow described above.
With reference to the FIG. 4 flow chart, in accordance with the present invention, simulation of an instance of a sequential module A proceeds as follows. If the combination of the current inputs to the sequential module A and its current state exists in the look-up table, then the stored output combinations for this instance of module A are used and the current state is updated to the next state from the look-up table. Otherwise, all state nodes of the module A are initialized to the values stored in the current state. All sequential sub-modules are initialized to their states as stored in the current state. The input stimulus is provided and this instance of module A is simulated. When simulation of this instance of module A is completed (i.e., either there are no pending events or the simulation time is up), the output values are returned to storage in the look-up table. The next state of the module is then created and the values of all state nodes and the states of all sequential sub-modules are stored in the next state. Not only the last obtained value of a state node, but also the other values it receives during the simulation are stored. If a state node changes value more than once (e.g., in case of a pulse), then all value changes are stored.
In addition to the state points described above, some sequential circuits may also have “transient state points.”
Sequential circuits have stable state points that are capable of retaining their state (logic value) even in the absence of any input directly driving these points. A method for automatically identifying stable state points in transistor level digital circuits is described in detail in co-pending and commonly assigned U.S. patent application Ser. No. 11/167,523, filed on Jun. 27, 2005, and titled “Method of Identifying State Nodes at the Transistor Level in a Sequential Digital Circuit.” In the method disclosed in application Ser. No. 11/167,523, a number of minimum combinatorial feedback loops that are present in the circuit are identified. Each minimum combinatorial feedback loop has at least one driver node. A driver node from each minimum combinatorial feedback loop is assigned to be a state node in accordance with predefined criteria. Application Ser. No. 11/167,523 is hereby incorporated by reference in its entirety to provide background information regarding the present invention.
In addition to stable state points, some custom designed digital circuits include what will be referred to herein as “transient state points.” A “transient state point” is defined as follows: a node that can directly affect the value of a state point and is combinatorially driven by inputs of the circuit, but the transition delay from at least one input to the node is greater than a predefined threshold value.
Transient state points need to be identified as state points for the hierarchical simulator of the present invention to function properly. This is the case because, after every simulation of a given module, the simulator “forgets” the values at all internal nodes in the circuit, except the state points (in case of sequential circuits). The next time the module is simulated, the state points are initialized to their logic values in the previous state. All other internal nodes are initialized to X (unknown) logic state. If the transient state points ate not identified as state points, then they too are initialized to X. Due to the propagation delay from the inputs, these points do not reach a valid logic value immediately. Since they can directly affect the value of stable state points, a stable state point can lose its value (and become X) if the transient state points remain at X for a considerable period of time. Hence, these points need to be identified as state points so that they will be initialized to a non-X logic value during the next simulation and prevent the stable state points from losing their values.
An example circuit containing transient state points is shown in FIG. 5 . In the FIG. 5 circuit, the stable state points are QB and QT, and can be detected by the state point detection algorithm described in above-referenced application Ser. No. 11/167,523. The nodes ag 0 and ag 0 b are transient state points, since they affect the stable state points and the propagation delay from the inputs to these nodes is higher than a predefined threshold. The FIG. 5 circuit is a module of a CMOS single-port SRAM circuit.
An algorithm for detecting transient state points in accordance with the concepts of the present invention will now be described with reference to the FIG. 6 flow chart.
A graph G=(V, E 1 , E 2 ) is defined where V is a set of vertices, E 1 is a set of directed edges, and E 2 is a set of undirected edges. There can be both a directed edge and an undirected edge between a pair of vertices in the graph. Given the schematic of a circuit containing stable state points, such a graph is constructed by applying the following rules: (1) for each node in the circuit (including input, output, inout and internal nodes of the circuit), a vertex is created in the graph, (2) for every transistor in the circuit, a directed edge is added from the vertex representing the gate node to the vertex representing the source node, a directed edge is added from the vertex representing the gate node to the vertex representing the drain node, and an undirected edge is added between the source and drain nodes, and (3) for every submodule in the circuit, a directed edge is added from each input of the sub-module to all of its outputs.
If there is a directed edge from vertex A to vertex B, then vertex A is denoted as the “parent” of vertex B. Two vertices connected by an undirected edge are called “peers.” The “weight” of all edges is taken as 1.
The graph created from the schematic of FIG. 5 in accordance with the FIG. 6 flow is shown in FIG. 7 . The power supply and group vertices have been omitted for brevity. The directed edges are shown as arrows and the undirected edges are shown as dotted lines.
Referring to the FIG. 8 flow chart, once a graph of the type shown in FIG. 7 has been created, the following steps are applied. Using only the directed edges, the all-pairs shortest path matrix of the graph is created, denoting the minimum path length between all pairs of vertices. This can be done using the standard Floyd Warshall's algorithm. If no path exists between a pair of nodes, then the path length is taken to be infinity. For each stable state point, a list of all it peers is made. For each such peer, if it is not an input or a stable state point, a list of all its parents is made. For each such parent, if it is not an input or a stable state point, if a path consisting of directed edges only exists from any input to the vertex, and the length of that path is greater than or equal 2, then it taken as a transient state point.
In the FIG. 7 graph, QB and QT are stable state points, and their peer is the vertex at. Vertex at has three parents: node ag 0 , node ag 0 b and CT. CT is an input, so it cannot be a state point. Paths exist from A and LME (both are inputs) to both node ag 0 and node ag 0 b , and each path is greater than or equal to two edges in length. Hence, node ag 0 and node ag 0 b are detected to be transient state points.
It should be understood that the particular embodiments of the invention described above have been provided by way of example and that other modifications may occur to those skilled in the art without departing from the scope and spirit of the invention as expressed in the appended claims and their equivalents.
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An integrated circuit design simulation method is provided that takes advantage of the fact that, when an instance of a circuit module has been simulated under a given set of input conditions, and the resulting output values and delays have been evaluated, another instance of the same module need not be re-simulated when it has the same input combination as the prior circuit module instance. The results computed earlier for the earlier circuit module instance can be re-used for the current circuit module instance.
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BACKGROUND OF THE INVENTION
This invention relates to the general health of a living cell, and to membrane potential as it relates to the general health and metabolic activity of a living cell. Specifically, this invention concerns methods of measuring and localizing relative changes in the membrane potential of a living cell, and relating such data to biochemical events occurring in the cell.
Qualitative measurements of gross changes in the health of a cell exposed to a suspected toxin have been made using techniques in the prior art such as the Draize test (Draize et al. (1945) Public Health Reports 60:377). In this in vivo test, a suspected toxin is placed in contact with the corneal tissues of the eye of a rabbit. Resulting injury and/or irritation resulting from the suspected toxin is then observed visually. However, besides being inhumane and expensive, this test measures the changes in multiple cells (corneal tissue) rather than a single cell, and test results are subjective, non-quantitative, and non-reproducible.
An alternative to this test is the in vitro occular toxicity test of Spilman et al. (The Toxicologist (1982) 2:A482) which monitors the effects of suspected toxins on cultured corneal cells instead of viable eyes. However, single cell measurements are not possible using this assay.
The general health of a cell can be reflected in its metabolic state. For example, a high level of respiration can be a good indication that the cell is functioning normally. A change in this rate may be indicative of the occurrence of a biochemical event in the cell, such as one resulting from an externally applied toxin or irritant.
Methods of measuring the average rate of respiration in multiple cells has been accomplished with the use of a Clark electrode. However, as in the Draize test, the metabolic state of a single cell cannot be determined by this method. Non-invasive methods such as NMR, appear promising, but do not, at present, have the necessary sensitivity to enable such a measurement.
Viability measurements do enable the examination of single cells. Vital staining, for example is routinely used as measure of cell viability. In this assay, live cells readily incorporate certain dyes which are not taken up by dead cells. Dye exclusion measurements are essentially similar to vital staining, except that it is the dead cells which show a preferential ability to incorporate the dye. However, such gross measurements are not indicative of the health or metabolic state of a particular cell per se. Moreover, there are no accurate methods for assessing the health of a single living cell.
The plasma and mitochondrial membranes of living cells are known to be characterized by specific trans-membrane potentials. In the case of mitochondria, a proton gradient exists across the inner membrane as the result of proton pumping by the respiratory chain located in this membrane. Mitochondrial membrane potential is not constant over time; many naturally occurring intracellular biochemical events routinely change the membrane potential. For example, the mitochondrial membrane potential is known to drive the synthesis of ATP, and in doing so, the potential changes or even becomes dissipated. The presence of irritants and injury to the cell also affect membrane potential.
The fluorescence and absorption characteristics of certain cationic dyes (e.g., cyanines, rhodamines, thiapyryliums, pyryliums) are known to be sensitive to membrane potential. The cyanine dyes, for example, demonstrate fluorescence and absorption changes as large as 80 when cells become negatively charged inside (hyperpolarized). Generally, this sensitivity of cyanine yes to membrane potential depends on the permeant nature of these cationic molecules. The distribution of these dyes between the cell interior and the medium is driven by the membrane potential (Chen (1988) Ann. Rev. Cell Biolol. 4:155-181), with the cationic dye being accumulated in cells when the cells become hyperpolarized.
Most accumulated cyanine dyes either (1) form aggregates that are nonfluorescent and absorb at a different wavelength then when outside a cell, (2) bind to the cell contents and the inner side of the membrane forming complexes that absorb or fluoresce at different intensities then when outside a cell, or (3) exhibit fluorescence quenching with little concomitant change in absorption. The particular mode of the optical change depends on the dye structure, the cell system being studied, and the experimental conditions.
Approaches to measuring the metabolic state of a single cell which involve the use of fluorescent dyes are promising in view of the predicted sensitivity (i.e., the ability to monitor single cells), the existence of more than 100,000 fluorescent dyes, the rapid development of hardware, the exquisite susceptibility of emission spectrum to environments, and the possibility of using non-invasive techniques. In fact, the energized state of mitochondria in vitro has been monitored using exogenous fluorescent dyes such as 1-anilino8-naphthalene sulfonate (ANS) and Oxonol V (Bashford et al. (1979) Meth. Enzymol. 55:569-586). Unfortunately, these dyes are not very membrane permeable, and thus their use has been limited to isolated mitochondria.
Other fluorescent dyes such as rhodamine 123 and various cyanines have been used to measure membrane potential. These dyes are able to penetrate the plasma and mitochondrial membranes of living cells where they fluoresce in a single spectral range or are quenched. In order to measure a cell's metabolic activity, such dyes have been used to label mitochondria, the organelles responsible for the respiratory functions and energy production in the cell; the degree to which mitochondria are present in a cell is directly proportional to the cell's metabolic activity.
Cyanine dyes in an aqueous solution may exist as three distinct molecular species: monomers; H-aggregates; and J-aggregates. Each species may be characterized by its unique absorption/fluorescence spectrum. The spectrum of a monomer usually consists of a broad peak with a vibrational shoulder at the shorter wavelength side. This peak has been called the M-band (for monomer). Dye aggregation may lead to a shift of the absorption maximum to a shorter wavelength (called H-aggregates or H-bands, for hypsochromic), or to a longer wavelength (called J-aggregates or J-bands for its discoverer, Jelly) (Jelly (1937) Nature 139:631-632). H-aggregates do not fluoresce, and this feature has been previously exploited for the measurement of membrane potentials (Cohen and Salzberg (1978) Rev. Physiol. Biochem. Pharmacol. 83:35-88: Bashford and Smith (1979) Meth. Enzymol. 55:569-586; Waggoner (1979) Ann. Rev. Biophys. Bioeng. 8:47-68; and Freedman (1981) Inter. Rev. Cytolo. 12:177-246). In contrast, J-aggregates are often intensely fluorescent. The wavelength of such fluorescence is very similar to the absorption wavelength of the J-aggregates. This lack of a Stoke's shift is termed "resonance fluorescence."
The rhodamine and the cyanine dyes used to date to measure respiration have failed to reveal any heterogeneity in fluorescent intensity among mitochondria within a single cell (see e.g., Johnson et al. (1981) J. Cell Biol. 88:526-535; and Cell (1982) 28:7-14). The human eye, photography, and video imaging all have limited ranges for a linear response to increasing light intensity. Consequently, once the fluorescent intensity reaches a certain level, prior art detection systems fail to respond to further increases in fluorescence. Mitochondria with higher potentials in the same cell are therefore difficult to distinguish from those with lower potentials because they are already brightly stained.
Furthermore, most previously used cyanines form H-aggregates rather than J-aggregates. As discussed above, H-aggregates quench the dye fluorescence. Thus, an increase in dye uptake as a result of higher mitochondrial membrane potential may not necessarily lead to brighter fluorescence; it may reduce the fluorescence to an extent that such mitochondria become undetectable.
Accordingly, it is an object of the present invention to provide a method of monitoring the general health of a single living cell.
Another object is to provide a method of measuring the respiratory state of a single cell, the state being indicative of the general health of the cell.
Yet another object is to provide a method of measuring the relative membrane potential in a living cell.
Still another object is to provide a method of monitoring the occurrence of a biochemical event in a cell.
Another object is to provide a method of determining to what extent a substance, to which a cell is exposed, poses a health risk to that cell.
SUMMARY OF THE INVENTION
The present invention provides methods of determining the relative mitochondrial membrane potential of a living cell. These methods include treating the cell with a composition comprising a lipophilic, cationic dye for a time sufficient to enable the dye to associate with the cell. This dye has a delocalized positive charge and the ability to undergo multiple changes in fluorescence spectra upon aggregation. In a preferred embodiments of the invention, 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanines such as bromide, chloride, iodide, and sulfonate salts of 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanines are used.
Following the treating of the cell, any dye which has not associated with the cell is then removed. The treated cell is exposed to light having a wavelength suitable for exciting the dye, so that the excited dye emits light having a wavelength different from the exciting light, or fluorescence. The fluorescence spectra, which is indicative of the relative membrane potential of the cell, is then determined.
In one embodiment of the invention, detection of the fluorescence is accomplished with an epifluorescence microscope, while in other embodiments, a fluorescence spectrophotometer or a flow cytometer are used.
This method can also be employed to detect a localized biochemical event in a living cell, wherein that event results in a change in the membrane potential of the cell. The spatial location of the biochemical event can be localized by identifying the location of fluorescence change in a particular part of the membrane. In one embodiment, an epifluorescence microscope is used to localize the fluorescence, while in an alternative embodiment, a fluorescence spectrophotometer is used.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other objects of the invention, the various features thereof, as well as the invention itself, may be more fully understood from the following description, when read together with the accompanying drawing in which:
FIG. 1 shows the molecular structure of 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanine iodide (JC-1);
FIG. 2 is a graphic representation of the effect of pH (A), ionic strength (B), and concentration (C), on the absorbance and fluorescence spectra of JC-1 in solution;
FIGS. 3A-3C are photographic representations showing the fluorescence of JC-1 taken up by human breast carcinoma MCF-7 cells and excited under green light (FIG. 3A), blue light (FIG. 3B), and light blue light (FIG. 3C);
FIG. 4 is a graphic representation of the effect of (A) and (B), concentration, and (C), mitochondrial membrane depolarization on the uptake and fluorescence of JC-1 by CX-1 cells;
FIGS. 5A and 5B are photographic representations of the epifluorescence localization of JC-1 in (FIG. 5A) untreated control CCL22 bovine kidney cells in high K + buffer, and (FIG. 5B) cells treated with nigerin and ouabain in high K + buffer; and
FIG. 6 is a photographic representation of the epifluorescence localization of JC-1 monomers and J-aggregates in the human foreskin fibroblast cell line, FS-2.
DESCRIPTION OF THE INVENTION
5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanines are lipophilic permeants with a delocalized positive charge. More specifically, bromide, iodide, chloride, and sulfonate salts of this cyanine are particularly useful in practicing the present invention. The molecular structure of one such cyanine, JC-1 is shown in FIG. 1A. JC-1 has been extensively used and studied as a sensitizer for silver halide-based photographic emulsion.
Like most cyanine dyes, JC-1 in aqueous solution may exist as three distinct molecular species: monomers; H-aggregates; and J-aggregates. The extent to which each species is present is governed by two distinct and reversible equilibria. One of these equilibria is governed by pH. For example, the apparent pKa of JC-1 is known to be 7.9. Above pH 7.9, the majority of JC-1 molecules have a single delocalized positive charge. One resonance form is shown in FIG. 1. Other resonance forms may be drawn in which the double bonds are shifted such that the positive charge falls on one of the other four nitrogen atoms. The conjugated electron system allows this species of JC-1 to absorb energy corresponding to visible blue-green wavelengths. Subsequent release of the absorbed energy results in the emission of green light.
Below pH 7.9, most of the JC-1 molecules are protonated as shown in FIG. 1B. Nuclear magnetic resonance studies have confirmed that the molecules are protonated at a carbon of the methine chain adjacent to the heterocyclic nuclei. Thus, JC-1 and other cyanines are carbon acids rather than the more common nitrogen acids.
Protonation at this position has two major consequences. First, the molecule now has an overall charge of +2. Second, the conjugated methine chain has been disrupted, resulting in the loss of absorbance and fluorescence of visible light. Unlike thia-, indo-, oxa-, or classic cyanines, the positive charges on the carbon acids of imidazolocyanines like JC-1 remain delocalized (i.e., resonance forms can still be drawn which place the positive charges on either nitrogen of each heterocyclic nucleus). Thus, these molecules remain lipophilic in their acid form.
FIG. 2A shows the fluorescence spectra of JC-1 at pH 8.2 (solid line) and pH 7.2 (dashed line) in 50 mM Tris-HCl containing 1% DMSO. As shown, J-aggregate formation is strongly favored by pH 8.2, the intramitochondrial pH.
A second equilibrium exists between monomers and aggregates consisting of dimers, trimers, or higher polymers. Factors such as ionic strength, dye concentration, temperature, and the presence or absence of organic deaggregants and organic solvents effect this equilibrium. For example, FIG. 2B shows representative absorbance spectra resulting from different ionic conditions. The first peak (absorption maximum=510 nm and fluorescence maximum =520 nm) is the monomeric dye species, and second peak (absorption maximum=585 nm and fluorescence maximum=585 nm) is the J-aggregate (Hada et al., 1977; Smith and Luss, 1972). The solid line is in 40% dimethyl sulfoxide (DMSO) in double distilled water at pH 7.2; the dashed line is 1% DMSO in high K + buffer. As shown, J-aggregate formation is favored by a buffer with ionic strength comparable to that inside the cells.
FIG. 2C shows the fluorescence spectra of JC-1 at various concentrations in 50 mM Tris-HCl, pH 8.2 containing 1% DMSO. The solid line is 200 ng/ml; the dashed line is 100 ng/ml; and the dotted line is 50 ng/ml. As shown, J-aggregate formation is highly concentration dependent.
These findings demonstrate that conditions favoring J-aggregation formation in aqueous environments include high ionic strength comparable to that found intracellularly, increased dye concentration, and higher PH. In addition, these findings indicate that the intramitochondrial environment should permit the formation of J-aggregates of JC-1.
That living cells can take up JC-1, and that JC-1 can fluoresces metachromasically is illustrated in FIG. 3. When cultured human breast carcinoma MCF-7 cells stained with JC-1 were examined by standard epifluorescence microscopy, visualization under green excitation with a narrow band pass filter produced red fluorescence (FIG. 3A); under blue excitation with a narrow band pass filter produced green fluorescence (FIG. 3B); and under light-blue excitation with a long-pass filter produced orange fluorescence (FIG. 3C). Although most mitochondria shown in FIG. 3C display orange fluorescence, there are also a few mitochondria with only green fluorescence. Orange regions indicate the presence of both green and red fluorescence, whereas green regions have no red fluorescence.
To establish that in living cells, green fluorescence represents the monomer and the red fluorescence represents the J-aggregate, human colon carcinoma CX-1 cells were incubated with different concentrations of JC-1, trypsinized, transferred to a cuvette, and analyzed by fluorescence spectrophotometry. FIG. 4A shows the fluorescence spectrum, obtained. The two peaks, at 520 nm and 585 nm correspond to the monomer fluorescence and the J-aggregate fluorescence, respectively (as demonstrated in FIG. 2). Thus, in living cells, the green fluorescence represents the monomer, and the red fluorescence the J-aggregate.
The results shown in FIG. 4A also confirm that J-aggregate formation is critically dependent on the concentration of JC-1 attained by mitochondria. CX-1 cells incubated with JC-1 at 1.25 μg/ml results in the formation of a very small amount of J-aggregate was observed; at 2.5 μg/ml, more was generated; at 5 μg/ml., the amount of J-aggregate greatly increased.
Effects of temperature and time on the uptake of JC-1 by living cells and J-aggregate formation therein were also investigated. No J-aggregate (no red fluorescence) was detected when MCF-7 cells were incubated at 4°C. with JC-1; a small amount was detected at 25°C.; and a large amount was detected at 37°C. The cells were then mounted in a live cell chamber containing 10 μg/ml of JC-1 in culture medium and maintained at 37°C. on a microscope stage with an air curtain. The uptake of JC-1 and formation of J-aggregates were monitored at 1 minute intervals by fluorescence microscopy: after 3 min., green fluorescence with a few speckles of red fluorescence was detected in mitochondria: at 5 min., the intensity of green fluorescence significantly increased, and rod-like structures with red fluorescence were detected; at 7 min., almost every mitochondrion exhibited red fluorescence; and after 10 min., all mitochondria were intensely illuminated with red fluorescence. Taken together, these results indicate J-aggregate formation is favored by higher temperatures and greater incubation times.
The uptake of lipophilic permeants (such as JC-1) with a delocalized positive charge is expected to be driven by membrane potential. To extend such an expectation to J-aggregate-forming dyes, the effects of a variety of drugs and ionophores were tested. FIG. 4B shows that in the presence of FCCP, a proton ionophore that abolishes the electrochemical gradient, very little J-aggregate was detected. These results suggest that the formation of J-aggregates is dependent on the presence of an electrochemical gradient. When cells were allowed to form J-aggregates, and then placed in medium containing FCCP, the J-aggregates rapidly disappeared (FIG. 4C). Therefore, the maintenance of J-aggregates in mitochondria is also dependent upon an electrochemical gradient. Other agents known to abolish the mitochondrial electrochemical gradient (including FCCP, dinitrophenol, azide plus oligomycin, antimycin A plus oligomycin, and rotenone plus oligomycin) not only prevented the formation of J-aggregates but also disintegrated preformed J-aggregates.
To identify the component of the electrochemical gradient that is responsible for the formation and maintenance of J-aggregates, the effects of two ionophores were investigated: valinomycin, a K+ ionophore that dissipates the membrane potential but not the pH gradient, and nigericin, a K+/H+ ionophore that abolishes the pH gradient but induces a compensatory increase in membrane potential with continued respiration. FIG. 5B shows that nigericin in the presence of ouabain to inhibit hyperpolarization of the plasma membrane) dramatically increases the formation of J-aggregates in CCL22 bovine kidney epithelial cells such that every mitochondrion had a detectable amount of J-aggregate in comparison with untreated controls. On the other hand, valinomycin substantially prevented the uptake of JC-1 and J-aggregate formation. When cells were prestained with JC-1 and placed in valinomycin or nigericin in the absence of dye, the former abolished the orange fluorescence and the latter had no observable effect.
These results indicate that the pH gradient is not required either for the uptake of JC-1 and subsequent formation of J-aggregates or for the maintenance of preformed J-aggregates. The component of the electrochemical gradient responsible for the formation and maintenance of J-aggregates in mitochondria is thus the membrane potential.
In living cells, mitochondria are surrounded by the plasma membrane whose potential has a pre-concentration effect on the mitochondrial accumulation of lipophilic cations (Davis et al., 1984). If J-aggregate formation is largely membrane potential dependent, a reduction in the plasma membrane potential should also lead to a reduction in J-aggregate formation. Indeed, the green fluorescence shown in FIG. 5A indicates that incubating CX-1 cells in high K + buffer dissipates the plasma membrane potential, thereby reducing formation of J-aggregate.
To determine if JC-1 is taken up equally and similarly by different cells, a variety of cell types and cell lines were treated with JC-1 at 10 μg/ml in culture medium for 10 minutes. In many of these cells, mitochondria were observed with simultaneous red fluorescence and green fluorescence in different regions. FIG. 6 shows such mitochondria in normal human foreskin fibroblasts.
The two equilibria discussed above may both be relevant to the formation of red and green mitochondria. When JC-1 is diluted from a stock solution into physiological buffer of pH 7.2, much of the JC-1 should exist as the uncolored, doubly positively charged carbon acid (the apparent pKa of the dye is 7.9). This species of JC-1 should be taken up by the cells in response to their Nernst potentials, since the molecule is a delocalized lipophilic cation. Once inside the mitochondria, however, this species of JC-1 will revert back to its basic, monomeric form and fluoresce green because the intramitochondrial pH is known to be 8.2. However, with continuous uptake of JC-1, J-aggregates will eventually form when the concentration of monomer reaches nadir.
The invention will be further understood from the following nonlimiting examples.
EXAMPLES
1. Cell Culture
"Normal" African green monkey kidney cell line CV-1 obtained from American Type Culture Collection (ATCC), (Rockville, MD), normal human fibroblast strain FS-2 (obtained from Dr. R. Sager (Dana-Farber Cancer Institute, Boston, MA), and human breast carcinoma cell line MCF-7 (obtained from Michigan Cancer Foundation, Detroit, MI) were grown in Dulbecco's modified Eagles' medium (GIBCO, Rockville, MD) supplemented with 10% calf serum (M.A. Bioproducts, Rockville, MD). Human colon carcinoma cell line CX-1 (obtained from Dr. S. Bernal, (Dana-Farber Cancer Institute, Boston, MA) were grown in 50% Dulbecco modified Eagles' medium and 50% RPMI 1640 medium (GIBCO) supplemented with 5% calf serum and 5% NuSerum (Collaborative Research, Lexington, MA). Bovine kidney epithelial cell line CCL22 (obtained from the ATCC); and normal mouse bladder epithelial cells (prepared essentially by the procedures of Summerhayes and Franks (1979) Proc. Natl. Acad. Sci. (USA) 79:5292-5296, herein incorporated by reference), were grown in F12 medium (GIBCO) supplemented with 10% fetal bovine serum (GIBCO). All cells were maintained at 37° C., 5% CO 2 and 100% humidity.
2. Staining of Cells for Microscopy
All cells were grown on 12 mm square glass coverslips (Bradford Scientific, Epping, NH), and stained with 50 μl of 10 μg/ml JC-1 (Polaroid Co., Cambridge, MA) in Dulbecco's modified Eagles' medium for 10 minutes in a cell culture incubator. Cells were rinsed in dye-free culture medium and mounted in a living cell chamber made of 0.7 mm thick silicon rubber (N.A. Reiss, Belle Mead, NJ) essentially as described by Johnson et al. ((1980) Proc. Natl. Acad. Sci. (USA) 77:990-994), herein incorporated as reference.
3. Fluorescence Microscopy
A Zeiss Axiophot Microscope (Woburn, MA) or a Zeiss Photomicroscope III equipped with epifluorescence optic was used to monitor fluorescence. Objective lenses used included Planapo 40X (N.A. 1.3), Planapo or Neofluar 100X (N.A. 1.2). A 100 W mercury bulb was used for either microscope. Microscopic images were recorded on Kodak Professional Ektamatic P800/1600 positive films at E.I. 800 and developed by E-6 process at Push 1. Color photographs were made with Ilford Cibachrome A-II papers developed by a Cibachrome automatic processor.
4. Spectrophotometric Analysis
A. JC-1 (10 μg/ml) in 40% dimethyl sulfoxide (DMSO) in double distilled water, PH 7.2, or in 1% DMSO in high K+buffer (3.6 mM NaCl, 137 mM KCl, 0.5 mM MgCl 2 , 1.8 mM CaCl 2 , 4 mM Hepes, 1 mg/ml dextrose, and 1% modified Eagles' medium amino acid solution [100X, GIBCO], PH 7.2) was placed in a 1 cm quartz cuvette and examined by a Beckman DU-70 spectrophotometer (San Diego, CA). The results are shown in FIG. 2A.
B. JC-1 at various concentrations (200 ng/ml; 100 ng/ml; and 50 ng/ml) was dissolved in 50 mM Tris-HCl, pH 8.2 containing 1% DMSO, mixed thoroughly for 10 minutes in a 1 cm quartz cuvette equipped with a magnetic stirrer, and examined as described in (A). The results are shown in FIG. 2B.
C. 200 ng/ml JC-1 was dissolved in 50 mM Tris-HCl containing 1% DMSO at pH 8.2 or pH 7.2.
D. Human breast carcinoma MCF-7 cells were stained with 10 g/ml JC-1 in culture media at 37° C. for 10 min. They were then examined by epifluorescence microscopy under green excitation, blue excitation with short pass filter, and light blue excitation under a filter that allows both red fluorescence from J-aggregate and green fluorescence from monomer to be detected simultaneously. The results are shown in FIG. 3.
E. CX-1 cells in culture medium were incubated with JC-1 at 1.25 ug/ml, 2.5 ug/ml, and 5 ug/ml. The results are shown in FIG. 4A.
F. Procedures were the same as in (E) except the JC-1 (10 μg/ml)-containing buffer was supplemented with 5 μM trifluoromethoxyphenyl hydrazone (FCCP) and 0.5% ethanol, or 0.5% ethanol. The results are shown in FIG. 4B.
G. Procedures were the same as in (E). After 10-20 minutes of incubation, the cells were then placed in cell medium containing 5 μM FCCP and 0.5% ethanol, or 0.5% ethanol, alone. The results are shown in FIG. 4C.
H. Human colon carcinoma cell line CX-1 in 60 mm culture dishes were grown to 50% confluence in 50% Dulbecco modified Eagles' medium and 50% RPMI 1640 medium supplemented with 5% calf serum (M.A. Bioproducts, (Rockville, MD) and 5% Nuserum (Collaborative Research, Lexington, MA) at 37 C. and 5% CO 2 . The cells were washed with (5 ml) and incubated in (1 ml) low K + buffer (137 mM NaCl, 3.6 mM KCl, 0.5 mM MgCl 2 , 1.8 mM CaCl 2 , 4 mM Hepes, 1 mg/ml dextrose, and 1% modified Eagles' medium amino acid solution [100X, GIBCO], pH 7.2) for 10 minutes. Cells were then washed three times with (2 ml each) and left in (1 ml) trypsin (1X, M.A. Bioproducts) in low K + buffer for 5 minutes. About 0.8 ml of cell suspension was mixed with 1.2 ml of low K + buffer in a 1 cm quartz cuvette for 5 minutes. Recordings of spectra from 550 to 620 nm were repeated at a higher detector sensitivity. The results are shown in FIG. 4A.
Fluorescent spectra were made as described in FIG. 3. Recordings of spectra from 550 to 620 nm were repeated at a higher detector sensitivity. The results are shown in FIG. 5 wherein JC-1 at 5 μg/ml in low K + buffer is solid curve, and 2.5 μg/ml is the dotted curve.
The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. For example, a combination of lipophilic, cationic dyes may be equally as effective in the method of the present invention. The present embodiments are therefore considered to be in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
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Disclosed is a method of detecting a localized biochemical event in a cell, wherein said event results in a change in the membrane potential of that cell. The method includes treating the cell with a composition containing a lipophilic, cationic dye having a delocalized positive charge and the ability to undergo multiple changes in fluorescence spectra upon aggregation. The cell is treated with the dye for a time sufficient to enable the dye to associate with the cell. Dye which has not associated with the cell is then removed. Fluorescence is observed when the cell is exposed to light having a wavelength suitable for exciting the dye. The spectrum obtained is indicative of the relative membrane potential of said cell, and a change in that membrane potential being indicative of the occurrence of a biochemical event.
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TECHNICAL FIELD
This invention generally relates to controllable coupling or clutch assemblies and, in particular, to such assemblies which have forward and reverse backlash.
OVERVIEW
Coupling assemblies such as clutches are used in a wide variety of applications to selectively couple power from a first rotatable driving member, such as a driving disk or plate, to a second, independently rotatable driven member, such as a driven disk or plate. In one known variety of clutches, commonly referred to as “one-way” or “overrunning” clutches, the clutch engages to mechanically couple the driving member to the driven member only when the driving member rotates in a first direction relative to the driven member. Further, the clutch otherwise permits the driving member to freely rotate in the second direction relative to the driven member. Such “freewheeling” of the driving member in the second direction relative to the driven member is also known as the “overrunning” condition.
One type of one-way clutch includes coaxial driving and driven plates having generally planar clutch faces in closely spaced, juxtaposed relationship. A plurality of recesses or pockets is formed in the face of the driving plate at angularly spaced locations about the axis, and a strut or pawl is disposed in each of the pockets. Multiple recesses or notches are formed in the face of the driven plate and are engageable with one or more of the struts when the driving plate is rotating in a first direction. When the driving plate rotates in a second direction opposite the first direction, the struts disengage the notches, thereby allowing freewheeling motion of the driving plate with respect to the driven plate.
When the driving plate reverses direction from the second direction to the first direction, the driving plate typically rotates relative to the driven plate until the clutch engages. As the amount of relative rotation increases, the potential for an engagement noise also increases.
Controllable or selectable one-way clutches (i.e., OWCs) are a departure from traditional one-way clutch designs. Selectable OWCs add a second set of locking members in combination with a slide plate. The additional set of locking members plus the slide plate adds multiple functions to the OWC. Depending on the needs of the design, controllable OWCs are capable of producing a mechanical connection between rotating or stationary shafts in one or both directions. Also, depending on the design, OWCs are capable of overrunning in one or both directions. A controllable OWC contains an extremely controlled selection or control mechanism. Movement of this selection mechanism can be between two or more positions which correspond to different operating modes.
U.S. Pat. No. 5,927,455 discloses a bi-directional overrunning pawl-type clutch, U.S. Pat. No. 6,244,965 discloses a planar overrunning coupling, and U.S. Pat. No. 6,290,044 discloses a selectable one-way clutch assembly for use in an automatic transmission. U.S. Pat. Nos. 7,258,214 and 7,344,010 disclose overrunning coupling assemblies, and U.S. Pat. No. 7,484,605 discloses an overrunning radial coupling assembly or clutch.
A properly designed controllable OWC can have near-zero parasitic losses in the “off” state. It can also be activated by electro-mechanics and does not have either the complexity or parasitic losses of a hydraulic pump and valves.
In a powershift transmission, tip-in clunk is one of most difficult challenges due to absence of a torque converter. When the driver tips-in, i.e., depresses the accelerator pedal following a coast condition, gear shift harshness and noise, called clunk, are heard and felt in the passenger compartment due to the mechanical linkage, without a fluid coupling, between the engine and powershift transmission input. Tip-in clunk is especially acute in a parking-lot maneuver, in which a vehicle coasting at low speed is then accelerated in order to maneuver into a parking space.
In order to achieve good shift quality and to eliminate tip-in clunk, a powershift transmission should employ a control strategy that is different from that of a conventional automatic transmission. The control system should address the unique operating characteristics of a powershift transmission and include remedial steps to avoid the objectionable harshness yet not interfere with driver expectations and performance requirements of the powershift transmission. There is a need to eliminate shift harshness and noise associated with tip-in clunk in a powershift transmission.
For purposes of this disclosure, the term “coupling” should be interpreted to include clutches or brakes wherein one of the plates is drivably connected to a torque delivery element of a transmission and the other plate is drivably connected to another torque delivery element or is anchored and held stationary with respect to a transmission housing. The terms “coupling”, “clutch” and “brake” may be used interchangeably.
A pocket plate may be provided with angularly disposed recesses or pockets about the axis of the one-way clutch. The pockets are formed in the planar surface of the pocket plate. Each pocket receives a torque transmitting strut, one end of which engages an anchor point in a pocket of the pocket plate. An opposite edge of the strut, which may hereafter be referred to as an active edge, is movable from a position within the pocket to a position in which the active edge extends outwardly from the planar surface of the pocket plate. The struts may be biased away from the pocket plate by individual springs.
A notch plate may be formed with a plurality of recesses or notches located approximately on the radius of the pockets of the pocket plate. The notches are formed in the planar surface of the notch plate.
Another example of an overrunning planar clutch is disclosed in U.S. Pat. No. 5,597,057.
Some U.S. patents related to the present invention include: U.S. Pat. Nos. 4,056,747; 5,052,534; 5,070,978; 5,449,057; 5,486,758; 5,678,668; 5,806,643; 5,871,071; 5,918,715; 5,964,331; 5,979,627; 6,065,576; 6,116,394; 6,125,980; 6,129,190; 6,186,299; 6,193,038; 6,386,349; 6,481,551; 6,505,721; 6,571,926; 6,814,201; 7,153,228; 7,275,628; 8,051,959; 8,196,724; and 8,286,772.
Yet still other related U.S. patents include: U.S. Pat. Nos. 4,200,002; 5,954,174; and 7,025,188.
U.S. Pat. No. 6,854,577 discloses a sound-dampened, one-way clutch including a plastic/steel pair of struts to dampen engagement clunk. The plastic strut is slightly longer than the steel strut. This pattern can be doubled to dual engaging. This approach has had some success. However, the dampening function stopped when the plastic parts became exposed to hot oil over a period of time.
Metal injection molding (MIM) is a metalworking process where finely-powdered metal is mixed with a measured amount of binder material to comprise a ‘feedstock’ capable of being handled by plastic processing equipment through a process known as injection mold forming. The molding process allows complex parts to be shaped in a single operation and in high volume. End products are commonly component items used in various industries and applications. The nature of MIM feedstock flow is defined by a science called rheology. Current equipment capability requires processing to stay limited to products that can be molded using typical volumes of 100 grams or less per “shot” into the mold. Rheology does allow this “shot” to be distributed into multiple cavities, thus becoming cost-effective for small, intricate, high-volume products which would otherwise be quite expensive to produce by alternate or classic methods. The variety of metals capable of implementation within MIM feedstock are referred to as powder metallurgy, and these contain the same alloying constituents found in industry standards for common and exotic metal applications. Subsequent conditioning operations are performed on the molded shape, where the binder material is removed and the metal particles are coalesced into the desired state for the metal alloy.
Other U.S. patent documents related to at least one aspect of the present invention includes U.S. Pat. Nos. 8,813,929; 8,491,440; 8,491,439; 8,286,772; 8,272,488; 8,187,141; 8,079,453; 8,007,396; 7,942,781; 7,690,492; 7,661,518; 7,455,157; 7,455,156; 7,451,862; 7,448,481, 7,383,930; 7,223,198; 7,100,756; and 6,290,044; and U.S. published application Nos. 2015/0000442; 2014/0305761; 2013/0277164; 2013/0062151; 2012/0152683; 2012/0149518; 2012/0152687; 2012/0145505; 2011/0233026; 2010/0105515; 2010/0230226; 2009/0233755; 2009/0062058; 2009/0211863; 2008/0110715; 2008/0188338; 2008/0185253; 2006/0124425; 2006/0249345; 2006/0185957; 2006/0021838; 2004/0216975; and 2005/0279602.
Some other U.S. patent documents related to at least one aspect of the present invention includes U.S. Pat. Nos. 8,720,659; 8,418,825; 5,996,758; 4,050,560; 8,061,496; 8,196,724; and U.S. published application Nos. 2014/0190785; 2014/0102844; 2014/0284167; 2012/0021862; 2012/0228076; 2004/0159517; and 2010/0127693.
A problem has arisen with some controllable one-way clutches (i.e. mechanical diodes (MD's)) which are meant to lock in one direction and lock or free wheel in the opposite direction, depending upon the position of a selector. In certain positions or locations, the clutch may not come out of a “lock-lock” condition (i.e. may inadvertently bind in both directions about the axis).
SUMMARY OF EXAMPLE EMBODIMENTS
An object of at least one embodiment of the present invention is to provide a controllable coupling assembly having forward and reverse backlash and which is prevented from inadvertently binding.
In carrying out the above object and other objects of at least one embodiment of the present invention, a controllable coupling assembly having forward and reverse backlash is provided. The assembly includes a plurality of forward locking elements. Each of the forward locking elements has a load-bearing surface. The assembly also includes at least one reverse locking element and first and second coupling members supported for relative rotation about a common rotational axis. The coupling members include a first coupling face having a set of forward pockets angularly spaced about the axis. Each of the forward pockets receives one of the forward locking elements and defines a forward load-bearing surface adapted for abutting engagement with the load-bearing surface of its respective forward locking element. The members also include a second coupling face which has a set of reverse locking formations adapted for abutting engagement with the at least one reverse locking element to prevent the relative rotation in a reverse direction about the axis and a third coupling face that opposes the first coupling face. The third coupling face has a set of forward locking formations. Each of the set of forward locking formations is adapted for abutting engagement with one of the forward locking elements to prevent the relative rotation in a forward direction about the axis. The number of forward locking elements is different than the number of reverse locking elements. The number of forward locking formations is different than the number of reverse locking formations. Either the forward backlash is a non-zero integer multiple of the reverse backlash or the reverse backlash is a non-zero integer multiple of the forward backlash to prevent the coupling assembly from inadvertently binding in both directions about the axis.
The assembly may further include a fourth coupling face that opposes the second coupling face. The fourth coupling face may have at least one reverse pocket. Each reverse pocket may receive a reverse locking element and may define a reverse load-bearing surface adapted for abutting engagement with a load-bearing surface of its respective reverse locking element.
The forward pockets may be grouped into at least one set wherein the forward pockets in each set are uniformly angularly spaced.
The forward pockets may be grouped into two or more sets.
The first coupling member may have the first and second coupling faces and the second coupling member may have the third coupling face.
The first coupling face may be oriented to face axially in a first direction along the axis, wherein the second coupling face may be oriented to face axially in a second direction opposite the first direction along the axis.
The forward and reverse locking elements may be locking struts.
The forward and reverse locking formation may be notches.
The first coupling member may be a splined ring.
The first and third coupling faces may be annular coupling faces that oppose each other.
The assembly may further include a plurality of reverse locking elements and a third coupling member having a fourth coupling face that opposes the second coupling face. The fourth coupling face may have a set of reverse pockets angularly spaced about the axis. Each of the reverse pockets may receive one of the reverse locking elements and defines a reverse load-bearing surface adapted for abutting engagement with a load-bearing surface of its respective reverse locking element.
The reverse pockets may be grouped into at least one set wherein the reverse pockets in each set are uniformly angularly spaced.
The reverse pockets may be grouped into two or more sets.
The assembly may further include a control member mounted for controlled, shifting movement between the second and fourth coupling faces relative to the set of reverse pockets and operable for controlling position of the reverse locking elements. The control member allows at least one of the reverse locking elements to engage at least one of the reverse locking formations in a first position of the control member wherein the control member maintains the reverse locking elements in their pockets in a second position of the control member.
The control member may comprise a slide plate controllably rotatable about the rotational axis between the first and second positions.
The assembly may further include a control element coupled to the control member to controllably shift the control member.
The assembly may further include a generally round snap ring that is received by an annular groove in the third coupling member to retain the members together and prevent axial movement of the members relative to one another.
Further in carrying out the above object and other objects of at least one embodiment of the present invention, a controllable clutch assembly having forward and reverse backlash is provided. The assembly includes a plurality of forward locking elements. Each of the forward locking elements has a load-bearing surface. The assembly also includes at least one reverse locking element and first and second clutch members supported for relative rotation about a common rotational axis. The clutch members include a first coupling face having a set of forward pockets angularly spaced about the axis. Each of the forward pockets receives one of the forward locking elements and defines a forward load-bearing surface adapted for abutting engagement with the load-bearing surface of its respective forward locking element. The members also include a second coupling face which has a set of reverse locking formations adapted for abutting engagement with the at least one reverse locking element to prevent the relative rotation in a reverse direction about the axis and a third coupling face that opposes the first coupling face. The third coupling face has a set of forward locking formations. Each of the set of forward locking formations is adapted for abutting engagement with one of the forward locking elements to prevent the relative rotation in a forward direction about the axis. The number of forward locking formations is different than the number of reverse locking formations. Either the forward backlash is a non-zero integer multiple of the reverse backlash or the reverse backlash is a non-zero integer multiple of the forward backlash to prevent the coupling assembly from inadvertently binding in both directions about the axis. The forward pockets are grouped into at least one set wherein the forward pockets in each set are uniformly angularly spaced.
The forward pockets may be grouped into two or more sets.
Yet still further in carrying out the above object and other objects of at least one embodiment of the present invention, a controllable coupling assembly having forward and reverse backlash is provided. The assembly includes a plurality of forward locking elements. Each of the forward locking elements has a load-bearing surface. The assembly also includes a plurality of reverse locking elements. Each of the reverse locking elements has a load-bearing surface. The assembly further includes first, second and third coupling members supported for relative rotation about a common rotational axis. The coupling members have a first coupling face with a set of forward pockets angularly spaced about the axis. Each of the forward pockets receives one of the forward locking elements and defines a forward load-bearing surface adapted for abutting engagement with the load-bearing surface of its respective forward locking element. The members also have a second coupling face with a set of reverse locking formations. Each of the set of reverse locking formations are adapted for abutting engagement with one of the reverse locking elements to prevent the relative rotation in a reverse direction about the axis. A third coupling face opposes the first coupling surface. The third coupling face has a set of forward locking formations. Each of the set of forward locking formations is adapted for abutting engagement with one of the forward locking elements to prevent the relative rotation in a forward direction about the axis. A fourth coupling face opposes the second coupling face. The fourth coupling face has a set of reverse pockets angularly spaced about the axis. Each of the reverse pockets receives one of the reverse locking elements and defines a reverse load-bearing surface adapted for abutting engagement with a load-bearing surface of its respective reverse locking element. The number of forward locking elements is different than the number of reverse locking elements. The number of forward locking formations is different than the number of reverse locking formations. Either the forward backlash is a non-zero integer multiple of the reverse backlash or the reverse backlash is a non-zero integer multiple of the forward backlash to prevent the coupling assembly from inadvertently binding in both directions about the axis.
The reverse pockets may be grouped into at least one set wherein the reverse pockets in each set are uniformly angularly spaced.
The above object and other objects, features, and advantages of the present invention are readily apparent from the following detailed description of the best mode for carrying out the invention when taken in connection with the accompanying drawings and in view of the prior art.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a controllable clutch or coupling assembly constructed in accordance with one embodiment of the present invention;
FIG. 2 is a view similar to the view of FIG. 1 but taken from a different direction to illustrate the bottom surfaces of the assembly;
FIG. 3 is a top plan view of a coupling member of another embodiment; and
FIG. 4 is a top plan view of a coupling member of yet another embodiment.
DETAILED DESCRIPTION
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.
Referring now to the drawing figures, FIGS. 1 and 2 are exploded perspective views (taken from different directions to illustrate different surfaces of the components of the assembly) of a controllable one-way clutch or coupling assembly, generally indicated at 10 , and constructed in accordance with one embodiment of the present invention. The assembly 10 includes an annular reverse pocket plate or first outer coupling member, generally indicated at 12 . An outer axially-extending surface 14 of the plate 12 has external splines 16 for coupling the plate 12 to the inner surface of a transmission case (not shown). An inner radially extending surface or coupling face 18 of the plate 12 is formed with spaced pockets 20 in which reverse struts 22 are pivotally biased outwardly by coil springs 27 . Preferably, sixteen reverse struts 22 are provided. However, it is to be understood that a greater or lesser number of reverse struts may be provide as will be described in greater detail herein below.
The assembly 10 also includes a control member or selector slide plate, generally indicated at 26 , having a plurality of spaced apertures 28 extending completely therethrough to allow the reverse struts 22 to pivot in their pockets 20 and extend through the apertures 28 to engage spaced locking formations or ramped reverse notches 30 formed in a radially extending surface or coupling face 32 ( FIG. 2 ) of an inner pocket plate or coupling member, generally indicated at 34 , when the plate 26 is properly angularly positioned about a common central rotational axis 36 by a shift fork or control element 38 which extends through a notch or slot (not shown) formed through an outer circumferential end wall 42 of the plate 12 . Preferably, 28 reverse notches are provided. However, it is to be understood that a greater or lesser number of reverse notches may be provided as will be described in greater detail herein below.
The fork 38 is secured or coupled to the control plate 26 so that movement of the fork 38 in the slot between different angular positions causes the plate 26 to slide or shift between its control positions to alternately cover or uncover the struts 22 (i.e., to engage or disengage the reverse struts 22 , respectively).
The plate 34 preferably comprises a splined ring having internal splines 46 formed at its inner axially extending surfaces 48 ( FIG. 2 ). A radially extending surface or coupling face spaced from the surface 32 of the plate 34 has a plurality of spaced pockets 52 ( FIG. 1 ) formed therein to receive a plurality of forward struts 54 therein which are pivotally biased by corresponding coil springs 55 . Preferably, fourteen forward struts 54 are provided. However, it is to be understood that a greater or lesser number of forward struts may be provided as will be described in greater detail herein below.
Referring collectively to FIGS. 1 and 2 , assembly 10 also includes a second outer coupling member or notch plate, generally indicated at 58 , which has a plurality of locking formations, cams or notches 60 formed in a radially extending surface or coupling face thereof by which the forward struts 54 lock the plate 34 to the notch plate 58 in one direction about the axis 36 but allow free-wheeling in the opposite direction about the axis 36 . Preferably, thirty two forward notches are provided. However, it is to be understood that a greater or lesser number of forward notches may be provided as will be described in greater detail herein below.
The notch plate 58 includes external splines 64 which are formed on an outer axial surface 66 of the plate 58 and which are received and retained within axially extending recesses 68 formed within an inner axially extending surface 70 of the end wall 42 of the plate 12 ( FIG. 1 ).
As shown in FIG. 1 , the assembly 10 further includes a snap ring, generally indicated at 72 , having end portions 74 and which fits within an annular groove 76 formed within the inner surface 70 of the end wall 42 of the plate 12 to hold the plates 12 , 26 , 34 and 58 together and limit axial movement of the plates relative to one another.
The shift fork 38 , in one control position of its control positions, disengages the reverse struts 22 . The shift fork 38 is rotated about 7° in a forward overrun direction about the axis 36 to rotate the selector plate 26 to, in turn, allow the reverse struts 22 to move from their disengaged positions in their pockets 20 to their engaged positions with the notches 30 .
As previously mentioned, many clutch assemblies (such as the assembly 10 described in FIGS. 1 and 2 as well as the assemblies 300 and 400 described herein below with respect to FIGS. 3 and 4 , respectively) are meant to lock in one direction and lock or free wheel in the opposite direction depending on the position of its selector or selector plate. In certain clutch locations, the clutch assembly would not come out of a “lock-lock” condition (i.e. would inadvertently bind in both directions about the rotational axis). This is due to the transitional backlash (i.e. distance the clutch can move between forward and reverse directions) was extremely low. This extremely low transitional backlash did not allow the locking elements or struts to drop out of their locking or binding position upon command thereby resulting in the “lock-lock” condition.
It was discovered for clutch assemblies having: 1) the number of forward locking elements different than the number of reverse locking elements; 2) the number of forward locking formations different than the number of reverse locking formations; and 3) either the forward backlash is a non-zero integer multiple of the reverse backlash or the reverse backlash is a non-zero integer multiple of the forward backlash that the coupling or clutching assembly was prevented from inadvertently binding in both directions about the rotational axis of its assembly.
When the above noted conditions are satisfied, the number of forward and reverse locking elements and the number of forward and reverse locking formations can be selected, so that minimum transitional backlash is substantially equal in all positions. The following table illustrates example possible combinations of forward and reverse locking elements (struts) and forward and reverse locking formations (notches):
Single/Dual
Forward
Single/Dual
Reverse
Function
Forward
Forward
Strut
Resolution
Reverse
Reverse
Strut
Resolution
without
Entry #
Notches
Struts
Engagement
(deg)
Notches
Struts
Engagement
(deg)
n
tie-up?
1
36
14
Dual
1.4276
84
1
Single
4.2857
3
Yes
2
32
14
Dual
1.6071
28
16
Dual
1.6071
1
Yes
3
24
14
Dual
2.1429
28
12
Dual
2.1429
1
Yes
4
26
18
Dual
1.5385
78
1
Single
4.6154
3
Yes
5
32
14
Dual
1.6071
112
1
Single
3.2143
2
Yes
6
38
12
Dual
1.5789
36
10
Dual
2.0000
1.267
No
7
34
12
Dual
1.7647
26
14
Dual
1.9780
1.121
No
Entry #2 is represented in FIGS. 1 and 2 . Entries 6 and 7 are examples of coupling assemblies which would experience the “lock-lock” or binding condition. The type of “engagement” (either “single” or “dual”) indicates either a single or two struts provide the locking function in one of the directions of rotation.
The above-noted discovery is applicable to any controllable ratcheting clutch assembly both radial and planar configurations such as the configurations shown in FIGS. 3 and 4 . FIG. 3 shows a planar concentric configuration of an assembly, generally indicated at 300 , including a reverse member or plate, generally indicated at 302 , which is grounded at 301 . The plate 302 has an outer surface or coupling face 304 with reverse struts (not shown) in reverse pockets 308 and an inner surface or coupling face 306 with forward notches 310 . The opposing clutch member which has the forward pockets and struts, coupling faces, and the corresponding reverse notches is not shown for simplicity. The resulting assembly 300 is a dual engagement assembly having 6 reverse pockets, 44 reverse notches (not shown), a reverse backlash of 2.727, 12 forward pockets (not shown), 22 forward notches, a forward backlash of 2.727° and a transitional backlash of 1.364°.
FIG. 4 shows a second planar concentric coupling assembly, generally indicated at 400 , including a reverse coupling member or plate, generally indicated at 402 , which is grounded at 401 . The plate 402 has an outer surface or coupling face 404 with reverse struts (not shown) in reverse pockets 408 and an inner surface or coupling face 406 with forward struts (not shown) in forward pockets 410 . The opposing coupling member or plate (not shown for simplicity) has corresponding coupling faces and forward and reverse locking formations. The resulting assembly 400 is a single engagement assembly having 8 reverse pockets (and struts), 25 reverse notches (not shown), a reverse backlash of 1.8°, 4 forward pockets (and struts), 50 forward notches (not shown), a forward backlash of 1.8° and a transitional backlash of 0.9°.
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.
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A controllable or selectable coupling assembly includes a plurality of forward locking elements, at least one reverse locking element and first and second coupling members supported for relative rotation about a common rotational axis. The coupling members include a first, second and third coupling faces. The first coupling face has a set of forward pockets angularly spaced about the axis. The second coupling face has a set of reverse locking formations adapted for abutting engagement with the at least one reverse locking element. The third coupling face opposes the first coupling face and has a set of forward locking formations. Either forward backlash is a non-zero integer multiple of reverse backlash or the reverse backlash is a non-zero integer multiple of the forward backlash to prevent the coupling assembly from inadvertently binding in both directions (i.e. a “lock-lock” condition) about the axis.
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This application is a continuation, of application Ser. No. 07/566,001 filed Aug. 13, 1990 and now abandoned.
BACKGROUND OF THE INVENTION
This invention generally relates to delivery systems for probes, and is specifically concerned with a flexible, hose-like delivery system for a pancake-type eddy current coil capable of remotely and reliably transmitting rotational motion through a small-diametered conduit, such as the heat exchanger tube of a nuclear steam generator.
Systems for delivering and rotating probes for the inspection of small-diametered conduits are known in the prior art. Such systems are particularly useful in delivering and rotating pancake-type eddy current coils within the heat exchanger tubes of nuclear steam generators in order to inspect these tubes for faults such as cracks or wall thinning. However, before either the utility or the limitations of such systems can be fully appreciated, some general background as to the structure, operation and maintenance of nuclear steam generators is necessary.
Nuclear steam generators are generally comprised of a bowl-shaped primary side, a tubesheet disposed over the top of the primary side, and a cylindrically shaped secondary side which in turn is disposed over the tubesheet. Hot, radioactive water from the reactor core circulates through the primary side of the steam generator, while non-radioactive water is introduced into the secondary side. The tubesheet hydraulically isolates but thermally connects the primary side to the secondary side by means of a number of U-shaped heat exchanger tubes whose bottom ends are mounted in the tubesheet. Hot, radioactive water from the primary side flows through the interior of these heat exchanger tubes while the exterior of these tubes comes into contact with the non-radioactive water in the secondary side in order to generate non-radioactive steam.
In the secondary side of such steam generators, the legs of the U-shaped heat exchanger tubes extend through bores present in a plurality of horizontally-oriented support plates that are vertically spaced from one another, while the ends of these tubes are mounted within bores located in the tubesheet. Small, annular spaces are present between these heat exchanger tubes and the bores in the support plates and the tubesheet which are known in the art as "crevice regions". Such crevice regions provide only a very limited flowpath for the feedwater that circulates throughout the secondary side of the steam generator, which causes "dry boiling" to occur wherein the feedwater boils so rapidly that these regions can actually dry-out during the operation of the generator. This chronic drying-out causes impurities in the water to precipitate and collect in these crevice regions. These precipitates ultimately creates sludge and other debris that promote the occurrence of corrosion in the crevice regions which, if not repaired, can ultimately cause the tube to crack and to allow radioactive water from the primary side to contaminate the non-radioactive water in the secondary side of the generator.
Eddy current probe systems were developed to monitor the extent to which the walls of such heat exchanger tubes were degraded as a result of corrosion. One of the latest generations of such probes are known as "pancake-type" eddy current probes. Such probes comprise a cylindrical body that is insertable within the interior of the tube to be inspected, and a small, relatively flat circular coil mounted on the side of the probe body. The coil is resiliently biased radially into wiping engagement with the inner wall of the heat exchanger tube. In operation, a miniaturized motor (operating through a gear train), and lead screw simultaneously rotate and linearly advance the probe body so that the small flat pancake coil that is resiliently mounted on the side of the probe body scans the interior wall of the heat exchanger tubes along a helical path.
While such prior art eddy current coil systems have proven themselves to be an effective tool in accurately and reliably inspecting the inner walls of heat exchanger tubes for cracks, pits, wall thinning and other degradations which are caused by corrosion, the applicant has observed a number of areas where such systems could stand improvement. For example, the miniaturized motors, drive trains and electric slip rings contained within the bodies of such probes to create the necessary helical movement of the pancake coil are expensive, and require a considerable amount of effort to assemble within the narrow confines of the probe body, whose diameter can only be about 0.50 inches in a probe system capable of inspecting heat exchanger tubes having a 0.625 inch outer diameter. These expenses are compounded by the fact that the probe bodies and all related delivery conduits are typically discarded after a single maintenance operation in a nuclear power plant due to radiation contamination. But even if they were not so discarded, the applicant has noticed that the electrical load placed upon the relatively delicate windings of the miniaturized motors used to create the required helical motion can prematurely jeopardize the reliable operation of these motors, and can ultimately cause them to burn out well before their expected lifetimes.
One possible solution to some of the problems associated with the prior art would be the development of more powerful and reliable miniature motors. However, further developments in such motors would be a relatively costly and time consuming endeavor, and still would not solve the cost problems associated with the fact that the probe bodies and all associated delivery conduits are typically discarded after a single maintenance operation. Another possible solution might be to remotely drive the probe body by means of a flexible power shaft that is mechanically coupled to a motor located well outside of the heat exchanger tube being inspected. However, known flexible power shafts are not compatible with either the pusher-puller mechanisms used to extend and withdraw the probe body into and out of the radioactive primary side of the generator, or with the robotic arms typically used to insert and withdraw this probe body from a selected heat exchanger tube within the primary side. Such puller-pusher mechanisms employ opposing, motor-driven rollers which are resiliently mounted to engage and drive a cable that is connected to the proximal end of the probe body in order to move the probe into and out of the primary side, while robotic positioners use reciprocating gripper mechanisms for extending and retracting first the probe body and then the cable attached thereto into and out of a heat exchanger tube. The resilient rollers and grippers used in these mechanisms would mechanically interfere with the transmission of torque if the probe body were directly connected to a flexible, rotating shaft. Of course, a flexible, plastic conduit might be placed over the rotating shaft in order to prevent such interference from occurring. However, experience has shown that the friction that develops between the flexible, rotating shaft and the inner walls of any such covering greatly interferes with the smooth transmission of torque over the distances required to remotely rotate a probe disposed within a heat exchanger tube in a nuclear steam generator. Moreover, such known flexible shafts are insufficiently flexible to be wrapped around the reels used in conjunction with known pusher-puller mechanisms.
Clearly, what is needed is a flexible delivery system for positioning and rotatably driving a probe at a desired position within a conduit such as a heat exchanger tube which obviates the need for expensive miniaturized motors, drive trains and slip rings. It would be desirable if such a system were relatively inexpensive so that it could be discarded after becoming radioactively contaminated incident to a single inspection and maintenance operation without major cost. Finally, it would be desirable if such a system were compatible with known pusher-puller mechanisms and robotic positioning devices, and were simple in construction, and reliable and accurate in operation.
SUMMARY OF THE INVENTION
Generally speaking, the invention is a flexible delivery system for positioning and rotatably supporting a probe, such as a pancake-type eddy current probe, at a desired position along the longitudinal axis of a conduit that transcends the limitations associated with the prior art. This system is particularly well adapted for the delivery of a rotatable probe within a small-diametered conduit such as the heat exchanger tubes used in nuclear steam generators, and comprises a flexible inner shaft having a distal end connected to the probe and a proximal end remotely connected to a shaft rotating means such as an electric motor, a flexible outer housing concentrically disposed around the inner shaft, and a plurality of bearing assemblies disposed between the inner shaft and the outer housing for reducing friction when the inner shaft rotates with respect to the outer housing.
The flexible inner shaft is formed from a plurality of relatively short, flexible shaft segments, and the bearing assemblies include opposing coupling means, which may be threaded ends, for coupling together the shaft segments. An electrical cable is disposed within the flexible inner shaft for providing electrical current to the coil of the probe. The electrical cable rotates along with the inner shaft, and is connected to a source of electrical current (such as an eddy current generated) through a slip-ring connector located outside of the steam generator at the proximal end of the cable. In the preferred embodiment, each of the bearing assemblies includes a centrally disposed bore for conducting the cable, which may include a pair of coaxial cables, while each of the shaft segments is formed from a spring-like section of Bowden shafting whose hollow interior forms a natural passageway for such cables. Additionally, each of the bearing assemblies includes at least three and preferably five ball bearings for minimizing friction between the inner shaft, and the interior walls of the flexible outer housing.
One side of each ball bearing is rollingly received within a semi-spherical recess in its respective bearing assembly, while the other side directly and rollingly engages the inner wall of the flexible outer housing. Thus the ball bearings are able to rollingly engage the interior walls of the outer housing in the circumferential direction when the flexible inner shaft is rotated, and in the longitudinal direction when the flexible outer housing is bent. The short, highly flexible segments of Bowden shafting material, in combination with the peripherally disposed ball bearing present in each of the bearing assemblies, provides a hose-like delivery system which is flexible enough to be wound about a reel of the type used in connection with state-of-the-art pusher-puller assemblies, and which is further capable of remotely transmitting rotational motion from, for example, the shaft of a motor located outside of the steam generator with minimal frictional losses and with a maximum amount of smoothness at low rpms.
An encoder assembly is located at the distal end of the outer housing just beneath the probe so that the system operator may accurately monitor the rate at which the inner shaft rotates the probe. A thrust bearing is provided between the probe and the distal end of the outer housing to further minimize friction. At the proximal end of the outer housing, a drive train is connected to the proximal end of the flexible inner shaft for turning it at a desired rate of rotation.
The flexibility of the hose-like delivery system, in combination with the low frictional losses associated with the inner shaft that drives the probe, provides a delivery system wherein the drive train, motor, and slip ring assembly may be remotely located well outside of the conduit that the probe is inserted into, thereby obviating the need for expensive and relatively unreliable miniaturized components.
BRIEF DESCRIPTION OF THE SEVERAL FIGURES
FIG. 1A is a perspective view of the proximal end of the flexible delivery system of the invention, illustrating how a state-of-the-art robotic positioning device may be used to insert and withdraw a probe rotatably supported by the system into and out of a selected heat exchanger tube in a nuclear steam generator;
FIG. 1B is a perspective view of the proximal end of the system, illustrating how it may be moved into and out of a manway in the primary side of a nuclear steam generator by means of a known pusher-puller mechanism;
FIGS. 2A and 2B, hereinafter collectively referred to as FIG. 2, are a side, cross-sectional view of the delivery system of the invention, illustrating both the encoder housing assembly of the system, and how the system rotatably supports the housing of a probe;
FIG. 3A is a side, cross-sectional view of the flexible cable used to remotely transmit torque from a drive train located out of the primary side of a nuclear steam generator to the probe; FIG. 3B is a cross-sectional view of the flexible cable illustrated in FIG. 3A along the lines 3B--3B, showing details of the structure of the bearing assemblies used to minimize friction between the inner shaft assembly, and the flexible outer housing of the flexible cable, and
FIG. 4 is a cross-sectional view of the drive train, motor and slip ring of the system used to drive the rotatable inner shaft assembly of the system and to conduct electricity through the inner shaft to the coil of the probe mounted at the distal end of the flexible cable.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
With reference now to FIGS. 1A and 1B, wherein like reference numerals designate like components throughout all the several figures, the purpose of the flexible delivery system 1 of the invention is to deliver and to rotatably support a probe 2 which may be a rotating, pancake-type eddy current probe within a small-diametered conduit, such as the heat exchanger tubes of a nuclear steam generator. The probe 2 includes an elongated, cylindrical housing 3 in which a pancake-type eddy current coil 4 is radially and resiliently mounted. The system further includes a flexible shaft segment 5 located just beneath the probe housing 3, and an encoder housing assembly 7 located just beneath the flexible shaft segment 5. Finally, the system includes a flexible cable 9 for transmitting both torque and electrical power to the probe 2. The flexible cable 9 is formed from a rotatable inner shaft assembly 11 that is contained within a non-rotatable, flexible outer housing 13 which, in the preferred embodiment, is formed from plastic tubing. A pair of coaxial cables 12a,b are disposed within the inner shaft assembly 11 for conducting alternating current to the coil 4 and to an encoder which will be described in more detail presently. A robotic positioner 14 (schematically illustrated in phantom) is used to insert and to withdraw the probe 2 and the flexible cable 9 into and out of a selected heat exchanger tube within a nuclear steam generator.
With reference now to FIGS. 1A and 1B, a guide tube 15 is used to guide the probe 2 and flexible cable 9 into and out of an open manway 16 located at the lower portion of the steam generator. The proximal end of the guide tube 15 terminates in a funnel 17 which helps to lead the probe 2 and flexible cable 9 initially into the guide tube 15 from a pusher-puller mechanism 19. In the preferred embodiment, the pusher-puller mechanism 19 may be a single or a multiple probe insertion device such as that disclosed and claimed in co-pending U.S. patent application Ser. No. 375,989, filed Jul. 6, 1989, and now U.S. Pat. No. 5,105,876 by Robert D. Burack et al. and assigned to the Westinghouse Electric Corporation. Such mechanisms 19 include a drive unit 21 which, as has been mentioned previously, contain opposing, resiliently mounted drive wheels which engage the flexible cable 9, and push it into or pull it out of the guide tube 15 disposed in the manway 16. Located directly behind the drive unit 21 is a reel 23 for storing and supporting the proximal portion of the flexible cable 9. The proximal end of the cable 9 extends out of the side of the reel 23 so that the proximal end of the inner shaft assembly 11 may be mechanically connected to a drive train 25 powered by an electric motor 27. Also connected to the proximal end of the inner shaft assembly is a slip ring 29 which is rotatably mounted upon a table-like platform 30. The purpose of the slip ring 29 is to conduct electrical current to the coaxial cables 12a,b disposed through the center of the inner shaft assembly 11 despite the rotational movement of these cables 12a,b by the drive train 25. To this end, the slip ring 29 includes a pair of leads 31 which may be connected, for example, to a MIZ-18 multiple frequency generator manufactured by Zetec located in Isaquah, Wash., and various encoder processing circuits (not shown).
As has been previously indicated, the primary purpose of the flexible delivery system 1 is to deliver and rotatably support a probe 2 within a heat exchanger tube 32 of a nuclear steam generator 34. The open ends of such heat exchanger tubes 32 are mounted in a tubesheet 36 which hydraulically isolates but thermally connects the primary side 37 of the generator 34 located beneath the tubesheet 36 to the secondary side 39 disposed over the tubesheet 36. If the delivery system 1 is to fulfill this purpose, its outer diameter can be no larger than between about 0.50 and 0.625 inches (1.27-1.59 cm); otherwise, it will not fit into the inner diameter of the heat exchanger tube 32.
With reference now to FIG. 2, a coupling 44 is provided for connecting the proximal end 45 of the probe housing 3 to the distal end 46 of the shaft segment 5. The coupling includes an annular shoulder 47 that circumscribes its distal end which is captured by a flange 48 located at the proximal end 45 of the probe body 3. Disposed within the coupling 44 at its distal end is an electrical connector assembly 50 which is supported by an internal annular shoulder 52. The electrical connector assembly 50 includes sockets for receiving pins (not shown) which are in turn connected to the leads of the pancake-type eddy current coil 4 disposed within the probe 2. These sockets are in turn connected to the coaxial cable 12, which is secured to the proximal end of the electrical connector assembly 50 by means of a nut 54. The proximal end of the coupling 44 includes a threaded recess 55 into which the distal end 46 of the shaft segment 5 is screwed. While the flexible shaft segment 5 may be formed from any one of several different types of commercially-available flexible shaft material, Bowden shafting is preferred due to its high strength and low weight. Such shafting material generally resembles a tight coil spring formed from spring steel in which adjacent coils come into contact with one another. The pitch of the spring steel coils which forms such shaft material forms a natural screw thread which can be engaged directly within the threaded recess 55 of the coupling 44.
A distal shaft coupling 58 connects the proximal end 60 of the flexible shaft segment 5 to the encoder housing assembly 7. Similarly, a proximal cable coupling 62 connects the distal end 64 of the flexible cable 9 to the proximal end of the encoder housing assembly 7. A support sleeve 65 connects the distal shaft coupling 58 with the proximal coupling 62. The relationship between these three components will now be described in greater detail.
The distal end of the shaft coupling 58 includes a conical leading edge 66, while its proximal end includes a cylindrical recess 67 for receiving the end of the support sleeve 65. The coupling 58 further includes a pair of radially disposed bores 68a,b for receiving a pair of securing pins 70a,b. These same securing pins 70a,b are receivable within opposing bores 72a,b present in the support sleeve 65. The proximal end of the support sleeve 65 includes threads 74 which are engageable with the distal end of one of the segments of Bowden shafting forming the inner shaft assembly 11. Hence, torque conducted through the inner shaft assembly 11 is conducted through the support sleeve 65 and from thence to the distal shaft coupling 58 and onward to the probe housing 3 through the flexible segment 5. The proximal cable coupling 62 concentrically overlies the proximal end of the support sleeve 65. The proximal end of the cable coupling 62 includes an annular recess 76 which is circumscribed by a plurality of barbed flanges 78 for receiving and securing the distal end of the flexible outer housing 13 to the cable coupling 62. A pair of bearings 80a,b are disposed between the outer diameter of the support sleeve 65 and the inner diameter of the proximal cable coupling 62 to minimize friction therebetween when the sleeve 65 rotates relative to the coupling 62.
An encoder assembly 82 is disposed between the bearings 80a,b which includes a pair of tick coils 84a,b. Each of these coils is mounted within a bore 86a,b provided in the central portion of the support sleeve 65. The outer ends of each of the tick coils 84a,b are encased in a plastic housing 88. A ferrite target 90 is secured within a bore present in the proximal cable coupling 62 in the same plane of rotation as the tick coils 84a,b. A securing nut 91 connects these tick coils 84a,b to one of the coaxial cables 12b that is disposed throughout the center of the inner shaft assembly 11. Coaxial cable 12b is, in turn, connected to a commercially-available encoder circuit (not shown). In operation, an alternating current is conducted through the tick coils 84a,b through the coaxial cable 12b. Whenever one of the coils 84a,b comes into alignment with the ferrite target 90, the electro-magnetic coupling between the field emanated by the coil 84a,b and the material forming the target 90 creates a change in impedance in the coils which in turn is detected by the encoder circuit (not shown). By measuring the periodicity of these impedance changes, the system operation can determine the rotational speed of the support sleeve 65, which in turn indicates the rotational speed of the probe housing 3.
The bearings 80a and 80b reduce the friction between the encoder housing assembly 7 and support sleeve 65. Bearing 80b is captured between an internal annular shoulder 92 and one side of the housings 88 surrounding the tick coils 84a,b, while bearing 80a is captured between these same housings and the proximal end 94 of a bearing cap connector 96. The bearing cap connector 96 is in turn secured onto the distal end of the cable coupling 62 by means of securing pins 98a,b which are insertable within mutually registrable bores present in the coupling 62 and the bearing cap connector 96. A thrust bearing 104 is provided between the non-rotating cable coupling 62, and the rotating shaft coupling 58 to reduce friction at this interface. The thrust bearing 104 is formed from a bearing retainer 106 into which a plurality of ball bearings 108 are slidably captured. A washer 110 in combination with a Bellville spring 112 biases the ball bearings 108 within the bearing retainer 106 against the previously mentioned bearing cap connector 96 to eliminate slack.
With reference now to FIGS. 3A and 3B, the flexible cable 9 includes an inner shaft assembly 11 disposed within a hose-like flexible outer housing 13. The inner shaft assembly 11 is formed from a plurality of relatively short shaft segments 115 made from the same Bowden shaft material at the previously discussed shaft segment 5. A plurality of shaft bearing assemblies 116 serve the dual function of interconnecting the shaft segments 115, and minimizing friction between the inner shaft assembly 11 and the inner wall of the flexible outer housing 13. Each of the shaft bearing assemblies includes a housing sleeve 118 having opposing, threaded ends 120a,b onto which the ends of adjacent shaft segments 115 may be screwed. A cable passageway 122 is disposed throughout the center of each of the housing sleeves 118 for conducting the previously mentioned pair of coaxial cables 12a,b. Disposed around the outer periphery of each of the housing sleeves 118 is a plurality of semispherical bearing recesses 124. In the preferred embodiment, five such recesses are provided, although as few as three may be used. Each of the bearing recesses 124 rollingly receives a ball bearing 126. In the preferred embodiment, each of the shaft segments 115 is of equal length, and the segments 115 are sufficiently short so that no segment 115 comes into direct contact with the inner wall of the surrounding flexible outer housing 13 when the flexible cable 9 is coiled around the reel 23 that feeds the cable 9 into the pusher-puller mechanism 19.
With reference now to FIG. 4, the drive train 25 that is connected to the proximal end of the flexible shaft segment 5 is provided with a drive pulley 131 that in turns rotates a driven pulley 133 by way of a belt 135. The drive pulley 131 is connected to the output shaft 136 of a gear train 137 which is turn is coupled to the output shaft (not shown) of the previously mentioned electric motor 127. The driven pulley 123 is in turn connected to a shaft 138 rotatably mounted onto the table-like platform 30 that has a centrally disposed bore 139. A coupler sleeve 140 is received within the bore 139 of the shaft 138. This sleeve includes a connecting flange 141 which is bolted or otherwise secured onto the front edge of the shaft 138. The proximal end of the coupler sleeve 140 is connected to the output of the previously mentioned slip ring 29, which in turn is secured and electrically connected to the proximal ends of each of the coaxial cables 12a,b. The distal end 143 of the coupler sleeve 140 is screwed into the coils of the most proximal of the shaft segments 115 forming the inner shaft assembly 11. A cable coupler 145 connects the proximal end of the flexible outer housing 13 of the cable 9 to the table-like platform 30. To minimize friction between the coupler 145 and the sleeve 140, a bearing 147 is provided in the position shown.
The operation of the system 1 of the invention may best be understood with reference to FIGS. 1A and 1B. First, the probe housing 3 and flexible cable 9 are unwound from the reel 9 and fed through the drive unit 21 of the pusher-puller mechanism 19 and from thence to the funnel 17 of the guide conduit 15. The robotic positioner 14 grasps the probe housing 3 of the system 1 as it exits the guide conduit 15. The robotic positioner 14 then proceeds to insert the probe housing 3 of the system 1 into the open end of a selected heat exchanger tube 32 until the coil 4 mounted within the probe housing 3 is directly adjacent a particular area of interest within the heat exchanger tube 32. At this juncture, the motor 27 of the drive train 25 is actuated while, at the same time, electrical currents are conducted through the coaxial cables 12a,b from the aforementioned variable frequency generator of the eddy current controller, and the encoder circuitry. In the preferred method of operation, the gear train 137 of the drive assembly 25 will be chosen so that the inner shaft assembly 11 is rotated at a rate of approximately 300 rpms. The rotational rate is constantly monitored by the system operator from the signals received from the previously described encoder assembly 82. A screw thread (not shown) mounted within the probe housing 3 converts the rotational movement of the housing 3 into a helical movement wherein the pancake coil 4 wipingly engages and helically scans the internal surface of the heat exchanger tube 32. After the coil 4 and traveled the maximum linear distance allowed by the aforementioned screw thread, the eddy current controller is shut down, and the direction of the motor 27 is reversed to re-position the pancake-type coil 4 into its proximal-most position within the probe housing 3. The process is then repeated after the robotic positioner 14 places the coil 4 adjacent to another area of interest within the same or a different heat exchanger tube 32.
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A flexible, hose-like delivery system for positioning and rotatably supporting a probe which may be a pancake-type eddy current probe at a desired position along the longitudinal axis of a small-diametered conduit such as the heat exchanger tube in a nuclear steam generator is disclosed. The system comprises a flexible inner shaft formed from a plurality of short segments of Bowden shafting which is connected to a drive train located remotely from the interior of the heat exchanger tube, a flexible outer housing preferably formed from a plastic conduit concentrically disposed around the inner shaft, and a plurality of ball bearing assemblies which interconnect the short shaft segments for minimizing the frictional engagement between the inner shaft and the interior walls of the flexible outer housing. The frictional losses between the inner shaft and the flexible tubular outer housing are small enough to allow rotational motion to be smoothly and reliably conducted over relatively long lengths and around bends, thus allowing such motion to be transmitted by remotely located, standard-sized drive trains and motors. The system eliminates the need for expensive, miniaturized drive trains, motors and slip ring components which, up to now, have accompanied such eddy current probes within such tubes.
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FIELD OF THE INVENTION
This invention relates to a method of operating a tandem mass spectrometer to improve signal-to-noise ratio of an ion beam. The invention has particular, but not exclusive, application to triple quadrupole mass spectrometers using electrospray ionization techniques.
BACKGROUND OF THE INVENTION
Tandem mass spectrometry is widely used for trace analysis and for the determination of ion structure. Commonly, the mass spectrometers used are quadrupole mass spectrometers which each have a set of four elongated conducting rods. In particular, triple quadrupole systems are widely used for tandem mass spectrometry. During operation, the mass resolving quadrupoles at either end of the triple quadrupole arrangement, are pumped to a relatively high vacuum (10 −5 Torr) while a central quadrupole is usually located in a collision cell and is maintained at a higher pressure for the purpose of promoting fragmentation of selected precursor ions.
Conventional resolving quadrupole mass spectrometers are subjected to both RF and DC voltages that require stringent length and machining requirements on the rod set. For instance, these rods are made of metallized ceramic, have a length of 20 cm or more and roundness tolerances better than 20 micro-inches and straightness tolerances better than 100 micro-inches. However, quadrupoles can also be operated in a condition where they are only subjected to RF voltages. In this case, the length limitation characteristic of RF/DC resolving quadrupoles no longer applies (rods as short as 2.4 cm may be used) and mechanical tolerances for rod roundness and straightness are considerably relaxed (tolerances of +/−{fraction (2/1000)} of an inch are used). Furthermore, there is no need for high precision, high voltage DC power supplies in the RF-only mode of operation.
When both DC and RF voltages are applied between the rod sets of the quadrupole, the quadrupole acts as a mass filter such that only ions of a pre-selected mass-to-charge ratio can pass therethrough for detection by an ion detector. The RF and DC voltages are varied depending on the frequency of operation and the mass range of interest. In the case of applying only an RF voltage to the quadrupole, the quadrupole acts as an ion pipe, transmitting ions over a wide mass-to-charge ratio while also permitting gas therein to be pumped away. Mass resolution can also occur in RF only quadrupoles since ions that are only marginally stable under a particular applied RF voltage gain excess axial kinetic energy due to the exit fringing field of the rod structure.
The structure and operation of a typical tandem mass spectrometer will now be described including commonly accepted designators for individual rod sets. Firstly, ions are produced from a trace substance that needs to be analyzed. These ions are guided and focused via an RF-only (typically 1 MHz) quadrupole rod set (Q 0 ) to a first mass spectrometer including a quadrupole rod set (Q 1 ), acting as a mass filter, for selecting parent or precursor ions of a particular mass-to-charge ratio. These selected precursor ions are then sent to another rod set (Q 2 ) that has collision gas supplied to it thus acting as a collision cell for the fragmentation of the selected precursor ions. Typically, a collision cell is only subjected to RF voltage. The fragment ions are then sent to a second mass analyzing quadrupole rod set (Q 3 ) that acts as a scannable mass filter for the daughter or fragment ions produced in the collision cell. A detector detects the ions selected in the second mass analyzing quadrupole, for recordal to generate a spectrum of the fragment ions. In tandem mass spectrometers, the gases used in the focusing rod set and the collision cell improve the sensitivity and mass resolution by a process known as collisional focusing (U.S. Pat. No. 4,963,736).
Unfortunately, known ion sources do not generate a pure stream of ions. Thus, mass spectra obtained from ions generated by atmospheric pressure ionization techniques such as electrospray ionization frequently contain many unwanted chemical components. These components are often due to cluster ion formation in the atmosphere-to-vacuum interface, the presence of which impedes identification of target analytes. In addition, there is sample dependent background noise from high velocity ions and clusters from the RF-only mass spectrometer. However, the inventor of the present invention has found that many of these unwanted cluster species are more fragile than the target analytes and can thus be discriminated against with the use of ion fragmentation techniques. This will allow for preferential detection of precursor ions.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a method of improving the signal to noise ratio of an ion beam, the method comprising:
(1) subjecting the ion beam to a first mass resolving step, to select precursor ions;
(2) colliding said precursor ions with a gas, to promote at least one of fragmentation and reaction of unwanted ions, whereby the unwanted ions generate secondary ions having a mass-to-charge ratio different from the mass-to-charge ratio of the precursor ions; and
(3) subjecting the ion beam including the secondary ions to a second mass resolving step, to reject ions with a mass-to-charge ratio different from the mass-to-charge ratio of the precursor ions, thereby increasing the signal-to-noise ratio of the ion beam.
Preferably the method includes effecting step (1) in a first mass spectrometer, step (2) in a collision cell, and step (3) in a second mass spectrometer. More preferably, the method includes scanning the first mass spectrometer through a range of mass-to-charge ratios and synchronously scanning the second mass spectrometer to select ions with the mass-to-charge ratio of the precursor ions. Alternatively, step (3) can be effected in a collision cell.
Depending on where step (3) is effected, the second mass spectrometer or the collision cell can either be operated to reject ions having a mass-to-charge ratio less than the mass-to-charge ratio of the precursor ions, or can be set to reject ions with mass-to-charge ratios both greater than and less than the mass-to-charge ratio of the precursor ions.
Preferably, the first and second mass spectrometers are quadrupole mass filters and the collision cell includes a quadrupole rod set. Further, the first and second mass spectrometers can be either one of a 3-dimensional ion trap mass spectrometer, a 2-dimensional ion trap mass spectrometer or a time-of-flight mass spectrometer. In addition, the second mass spectrometer can be provided as a quadrupole operated in RF-only mode with a q value between 0.6 and 0.907.
The collision cell can include an RF quadrupole or multipole having RF voltage applied to it which can be adjusted such that the precursor ions of interest emerging from the first mass spectrometer are transmitted to the second mass spectrometer. This collision cell contains neutral gas to promote collisional activation and subsequent fragmentation of the unwanted ions.
An alternative method would be to apply a resolving DC voltage to the second mass spectrometer while maintaining a q value near 0.706. This resolving DC voltage enhances the selectivity of the precursor ions over the unwanted ions.
As noted above, another alternative method would be to operate the collision cell with a and q parameters such that only the precursor ions of interest are stable and thus transmitted to the ion detector. This avoids the need for a second mass spectrometer.
Thus, this method increases the signal-to-noise ratio of an ion beam containing an analyte ion species with fragmentation thresholds greater than unwanted chemical species in the ion beam such as clusters that are more fragile than the analytes of interest. This results in considerable spectral simplification and easier identification of the analyte ions of interest. The ion beam can then be subject to further steps of fragmentation and/or reaction by mass analysis, in known manner.
Further objects and advantages of the invention will appear from the following description, taken together with the accompanying drawings.
DETAILED DESCRIPTION OF THE DRAWINGS
For a better understanding of the present invention and to show more clearly how it may be carried into effect, reference will now be made, by way of example, to the accompanying drawings which show a preferred embodiment of the present invention and in which:
FIG. 1 is a schematic description of a conventional triple quadrupole mass spectrometer;
FIG. 2 is a conventional quadrupole stability diagram;
FIG. 3 a is an electrospray ionization mass spectrum of minoxidil and reserpine obtained by scanning the first and second mass analysis sections of the spectrometer of FIG. 1, without collision gas in the collision cell; and
FIG. 3 b is an electrospray ionization mass spectrum of minoxidil and reserpine obtained by scanning the first and second mass analysis sections with collision gas in the collision cell and operating the second mass spectrometer at q=0.78 for the precursor ions emerging from the first mass spectrometer.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring first to FIG. 1, a schematic of a conventional triple quadrupole mass spectrometer is displayed and is given the general reference 10 . In known manner, the apparatus 10 includes an ion source 12 , which may be an electrospray, an ion spray, a corona discharge device or any other known ion source. The ion source 12 could be either pulsed or continuous. Ions from the ion source 12 are directed through an aperture 14 in an aperture plate 16 into conventional curtain gas chamber 18 , which is supplied with curtain gas from a source (not shown). The curtain gas can be argon, nitrogen or another inert gas as described in U.S. Pat. No. 4,861,988, Cornell Research Foundation Inc. (which also discloses a suitable ion spray device).
The ions then pass through an orifice 19 in an orifice plate 20 and enter a differentially pumped vacuum chamber 21 . The ions pass through an aperture 22 in a skimmer plate 24 and enter a vacuum chamber 26 . Typically, the differentially pumped vacuum chamber 21 has a pressure on the order of 2 Torr and the vacuum chamber 26 is evacuated to a pressure of about 7 mTorr. The vacuum chamber 26 is considered to be the first ‘vacuum’ chamber due to the low pressure contained therein. Conventional pumps and associated equipment are not shown for simplicity.
The first vacuum chamber 26 contains an RF-only multipole ion guide 27 , also identified as Q 0 (the designation Q 0 indicates that it takes no part in the mass analysis of the ions). This can be any suitable multipole, but typically a quadrupole rod set is used. The function of RF-only multiple ion guide 27 is to cool and focus the ions, and it is assisted by the relatively high gas pressure present in the first vacuum chamber 26 . Vacuum chamber 26 also serves to provide an interface between ion source 12 , which is at atmospheric pressure, and subsequent lower pressure vacuum chambers, thereby serving to remove more of the gas from the ion stream, before further processing.
The ions then pass through an aperture 28 on an interquad plate IQ 1 , which separates vacuum chamber 26 from a second or main vacuum chamber 30 . The main vacuum chamber 30 contains RF-only rods 29 , a mass resolving spectrometer 31 , an interquad aperture plate IQ 2 , a collision cell 33 , an interquad aperture plate IQ 3 and a mass resolving spectrometer 37 . Following the mass resolving spectrometer 37 is exit lens 40 , having an aperture (not shown) and ion detector 46 . Main vacuum chamber 30 is evacuated to approximately 1×10 −5 Torr.
The RF-only rods 29 are of short axial extent and serve as a Brubaker lens. The mass resolving spectrometer 31 includes a quadrupole rod set Q 1 . The collision cell 33 , including a quadrupole rod set 32 (also identified as Q 2 ), is supplied with collision gas from a collision gas source 34 . The collision cell 33 is preceded by the interquad aperture plate IQ 2 , having an aperture 35 , and is proceeded by the aperture plate IQ 3 , having an aperture 36 . The collision cell 33 thus defines an intermediate chamber. The mass resolving spectrometer 37 includes a quadrupole rod set Q 3 .
Conventionally, the rod sets Q 1 and Q 3 of the mass resolving spectrometer 31 and mass resolving spectrometer 37 have both RF and DC applied thereto, from power supplies 42 and 44 , to act as resolving quadrupoles, transmitting ions within a specified mass-to-charge (m/z) window. The quadrupole rod set Q 2 is coupled to the quadrupole rod set Q 3 via a capacitive network (not shown) so that the quadrupole rod set Q 2 is subject to just an RF signal.
The present inventor has realized that many background species, such as cluster ions, fragment much more readily than do many analyte compounds. The present invention takes advantage of this behaviour. Therefore, to detect analyte ions in the presence of high concentrations of easily fragmented background ions, the mass resolving spectrometer 31 , comprising the quadrupole rod set Q 1 , is scanned through an m/z range of interest. The transmitted ions are then directed into pressurized collision cell 33 at a collision energy sufficient to dissociate the background ions, but insufficient to fragment the analyte ions. This collision energy is dependent on the analyte ions of interest and the background ions. The second mass resolving spectrometer 37 , comprising the third quadrupole rod set Q 3 , is then scanned synchronously with the first mass resolving spectrometer 31 , such that the unfragmented precursor ions are transmitted to ion detector 46 while lower m/z fragment ions from the background precursor ions are discriminated against.
The stability conditions (i.e. the stability of the ions) in a quadrupole mass spectrometer are dictated by the Mathieu a and q parameters where:
a= 8 eU /( mΩ 2 r 0 2 ) (1)
q= 4 eV /( mΩ 2 r 0 2 ) (2)
where:
U is the amplitude of the DC voltage applied to the rods;
V is the amplitude of the RF voltage applied to the rods;
e is the charge on the ion;
m is the mass of the ion;
Ω is the RF frequency; and
r 0 is the inscribed radius of the rod set.
A plot of values for the Mathieu a and q parameters illustrates the ion stability region which is possible for various RF and DC voltages and various ion m/z ratios. RF and DC voltages can then be chosen to create a scan line that determines which ion masses will be stable in the mass spectrometer. For instance, in known manner, RF and DC voltages can be chosen to select a scan line which passes through the tip 50 of the stability diagram shown in FIG. 2 with q being approximately equal to 0.706. Alternatively, RF-only operation of the quadrupole corresponds to a scan line with a equal to 0 (i.e. no applied resolving DC). As FIG. 2 shows, the first stability region requires that an ion has Mathieu a and q parameters that are chosen to be less than 0.237 and 0.908 respectively and that are below the curve indicating the boundary of the stability region shown.
In the first embodiment of the method of the present invention, the first mass resolving spectrometer 31 is operated at the tip 50 of the stability diagram shown in FIG. 2 while the collision cell 33 and the second mass resolving spectrometer 37 are operated in RF-only mode. The q value of the second mass resolving spectrometer 37 is chosen to be between 0.6 to 0.907 for the precursor ions emerging from the first mass resolving spectrometer 31 . This value of q was chosen to ensure that the unfragmented precursor ions will be transmitted through the second mass resolving spectrometer 37 to the detector 46 while lower m/z fragment ions with q values greater than 0.907 will be rejected by the second mass resolving spectrometer 37 and thus will not be detected. The second mass resolving spectrometer 37 is operated in RF-only mode in order to maintain high sensitivity, i.e. to ensure high efficiency in transmitting the precursor ions.
FIG. 3 a shows a typical mass spectrum of a mixture of 50 pg/μL each of minoxidil and reserpine using electrospray ionization. No collision gas was added to the collision cell 33 and the second mass resolving spectrometer 37 was scanned synchronously while utilizing a q value of 0.78. As such, both the collision cell 33 and the second mass resolving spectrometer 37 acted as ion guides with no resolving effect; all mass analysis/resolution was provided by the first mass resolving spectrometer 31 . The known minoxidil and reserpine analytes, which are located at m/z values of 210 atomic mass units (amu) ( 60 on FIG. 3 a ) and 609 atomic mass units ( 70 on FIG. 3 a ), are difficult to identify due to the large number of background species in the mass spectrum.
FIG. 3 b shows the improvement in spectral analysis achieved from the addition of a collision gas to collision cell 33 and using a 20 eV laboratory collision energy (in known manner, the reference to “laboratory” simply indicates the frame of reference). In known manner, varying DC potentials are provided along the length of the spectrometers to displace ions through the spectrometers. The collision energy was provided by an appropriate potential drop between the DC rod offset values of mass resolving spectrometer 31 and the collision cell 33 . This promotes fragmentation of unwanted background ions, while largely not fragmenting the desired analyte ions. The fragments, with lower m/z ratios, are then rejected in the second mass resolving spectrometer 37 . The minoxidil and reserpine analyte ions are now easily identified because most of the background ion spectral peaks have been eliminated. Closer inspection of the two spectra in FIG. 3 shows that the intensities of many of the background ions have been reduced by more than a factor of 500, Meanwhile, the minoxidil intensity has only been diminished by about 30% and there has been no loss in the reserpine ion intensity. Thus it is clear that the signal-to-noise of the ion beam whose spectrum is shown in FIG. 3 b is superior to that of FIG. 3 a , however, it is to be borne in mind that the signal-to-noise improvements of the described method rely on the background ions being more fragile than the analyte ions. Consequently, the method of the present invention will not discriminate against background ions that are more stable than the analyte ions.
A second embodiment of the method of the present invention involves the addition of a resolving DC voltage to the second mass resolving spectrometer 37 while maintaining a q value near 0.706, i.e. the q value at peak 50 in FIG. 2 . The second mass resolving spectrometer 37 will then reject both lighter and heavier ions outside a pass band established around q=0.706. This will enhance the selectivity of precursor ions over fragment ions at the expense of sensitivity since a narrower m/z window is stable in the second mass resolving spectrometer 37 .
A third embodiment of the method of the present invention involves selecting the a and q parameters of collision cell 33 such that only precursor ions emerging from the first mass resolving spectrometer 31 are stable throughout the length of the collision cell 33 . In this case there is no explicit need for the presence of the second mass resolving spectrometer 37 since mass discrimination is carried out by the collision cell 33 . However, it must be understood that, due to the presence of gas in collision cell 33 , precise mass selection is not possible; i.e. the boundaries between ions with m/z ratios that are transmitted and those that are rejected, are blurred and imprecise. Thus, RF and DC voltages are such as to establish a wide pass band that promotes passage of the precursor ions of interest, while rejecting ions with an m/z ratio significantly different from the precursor ions. In this case, the second mass resolving spectrometer 37 could be utilized to enhance the discrimination, by being set to a narrow pass band.
In the present invention, there are no critical values for collision energy, collision gas pressure or the nature of the collision gas. Rather, the optimum values of these parameters are analyte dependent. Furthermore, although the method of the present invention is particularly effective for electrospray ionization, it may also be useful for ions generated via atmospheric pressure chemical ionization, atmospheric pressure photoionization and matrix assisted laser desorption ionization. All of these techniques are forms of atmospheric pressure ionization except for the last technique which can be carried out within a vacuum chamber.
The present invention as described is solely for the purpose of cleaning up an initial ion current or signal, so as to provide a stream of precursor ions with an improved signal-to-noise ratio, i.e. with fewer unwanted ions. In particular, the invention addresses the problem of unwanted ions from atmospheric pressure ionization sources, e.g. electrospray sources. It will be understood by those skilled in this art that, having established a stream of precursor ions with a good signal-to-noise ratio, these precursor ions can be handled, processed and analyzed in accordance with any known technique. Thus, the precursor ions can be passed into a further fragmentation or collision cell configured and operated to promote fragmentation/reaction of the precursor ions. The resulting product ions can then be subject to separate mass analysis, or indeed subject to further fragmentation/reactions steps for MS/MS, MS/MS/MS or MS n analysis and the like. For instance, for MS/MS analysis, precursor ions are selected in a first mass selection stage, the precursor ions are then passed into a collision cell to promote fragmentation and/or reaction of the precursor ions (note that here it is fragmentation of the precursor ions that is being promoted, rather than fragmentation of unwanted ions as in the present invention), and a second, downstream mass analyzer is then used to analyze the product ions.
The method of the present invention described herein can also be employed with any combination of mass analyzers separated by a fragmentation region. Other mass spectrometers include, but are not limited to, time-of-flight mass spectrometers, three-dimensional ion trap mass spectrometers, two-dimensional ion trap mass spectrometers, and Wein filter mass spectrometers.
It should be understood that various modifications can be made to the preferred embodiments described and illustrated herein, without departing from the present invention, the scope of which is defined in the appended claims.
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A method of improving the signal to noise ratio of an ion beam, utilizing a tandem mass spectrometer comprising two mass filters separated by a collision cell. The first mass filter is operated in a resolving mode such that only a narrow mass-to-charge range of precursor ions are stable and accelerated towards the collision cell which contains neutral gas to promote collisional activation and subsequent fragmentation of unwanted fragile ions while minimizing fragmentation of desired analyte ions. The second mass filter is scanned synchronously with the first mass filter such that only ions that do not fragment are recorded by the ion detector. Thus, analyte ions that have fragmentation values higher than unwanted background ions are preferentially detected thereby increasing the signal-to-noise ratio of the ion beam.
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RELATED APPLICATIONS
This application is a Continuation-In-Part of U.S. parent application Ser. No. 10/229,407 filed 28 Aug. 2002 now abandoned and Continuation-In-Part Application Ser. No. 10/647,557 filed 25 Aug. 2003, now abandoned, which applications are hereby incorporated by reference.
TECHNICAL FIELD
This invention relates to liquid hydraulic pump/motor machines appropriate for relatively “heavy duty” automotive use, e.g., for hydraulic transmissions used for vehicle locomotion and/or for the storing and retrieval of fluids in energy-saving accumulator systems. [Note: the term “liquid” is used to distinguish from “gas” hydraulic pumps, e.g., pumps for compressing air and/or other gases.]
BACKGROUND
Hydraulic pumps and motor are well known and widely used, having reciprocating pistons mounted in respective cylinders formed in a cylinder block and positioned circumferentially at a first radial distance about the rotational axis of a drive element. Many of these pump/motor machines have variable displacement capabilities, and they are generally of two basic designs: (a) either the pistons reciprocate in a rotating cylinder block against a variably inclined, but otherwise fixed, swash-plate; or (b) the pistons reciprocate in a fixed cylinder block against a variably inclined and rotating swash-plate that is often split to include-a non-rotating (i.e., nutating-only) “wobbler” that slides upon the surface of a rotating and nutating rotor. While the invention herein is applicable to both of these designs, it is particularly appropriate for, and is described herein as, an improvement in the latter type of machine in which the pistons reciprocate in a fixed cylinder block.
As indicated above, this invention is directed to “liquid” (as distinguished from “gas”) type hydraulic machines and it should be understood that the terms “fluid(s)” and “pressurized fluid(s),” as used herein throughout the specification and claims, are intended to identify incompressible liquids rather than compressible gasses. Because of the incompressibility of liquids, the pressure and load duty cycles of the these two different types of hydraulic machines are so radically different that designs for the gas compression type machines are inappropriate for use in the liquid-type machines, and visa versa. Therefore, the following remarks should all be understood to be directed and applicable to liquid-type hydraulic machines and, primarily, to such heavy duty automotive applications as those identified in the Technical Field section above.
Hydraulic machines with fixed cylinder blocks can be built much lighter and smaller than the machines that must support and protect heavy rotating cylinder blocks. However, these lighter machines require rotating and nutating swash-plate assemblies that are difficult to mount and support. For high-pressure/high-speed service, the swash-plate assembly must be supported in a manner that allows for the relative motion between the heads of the non-rotating pistons and a mating flat surface of the rotating and nutating swash-plate. As just indicated above, such prior art swash-plates have often been split into a rotating/nutating rotor portion and a nutating-only wobbler portion, the latter including the flat surface that mates with the heads of the non-rotating pistons through connecting “dog bones”.
That is, such fixed-cylinder-block machines have heretofore used a “dog-bone” extension rod (i.e., a rod with two spherical ends) to interconnect one end of each piston with the flat surface of the nutating-but-not-rotating wobbler. One spherical end of the dog bone is pivotally mounted into the head end of the piston, while the other spherical end is usually covered by a pivotally-mounted conventional “shoe” element that must be held at all times in full and flat contact against the flat surface of the swash-plate wobbler during all relative motions between the heads of the non-rotating pistons and a mating flat surface of the nutating swash-plate. As is well known in the art, these relative motions follow varying non-circular paths that occur at all inclinations of the swash-plate away from 0°. These dog-bones greatly increase the complexity and cost of building the rotating swash-plates of these lighter machines.
Dog-bone rods are also sometimes used to interconnect one end of each piston with the inclined (but not rotating) swash-plates of hydraulic machines with rotating cylinder blocks. However, more often this latter type of machine omits such dog-bones, using instead elongated pistons, each having a spherical head at one end (again, usually covered by a pivotally-mounted conventional shoe element) that effectively contacts the non-rotating flat surface of the swash-plate. Such elongated pistons are designed so that a significant portion of the axial cylindrical body of each piston remains supported by the walls of its respective cylinder at all times during even the maximum stroke of the piston. This additional support for such elongated pistons is designed to assure minimal lateral displacement of each spherical piston head as it slides over the inclined-but-not-rotating swash-plate when the pistons rotate with their cylinder block.
Generally, these elongated pistons are primarily lubricated by “blow-by”, i.e., that portion of the high pressure fluid that is forced between the walls of each cylinder and the outer circumference of each piston body as the reciprocating piston drives or is driven by high pressure fluid. Such blow-by provides good lubrication only if tolerances permit the flow of sufficient fluid between the walls of the cylinder and the long cylindrical body of the piston, and blow-by sufficient to assure good lubrication often negatively effects the volumetric efficiency of the pump or motor machine. For instance, a 10 cubic inch machine can use as much as 4 gallons of fluid per minute for blow-by. While smaller tolerances can often be used to reduce blow-by, the reduction of such tolerances is limited by the needs for adequate lubrication that increase with the size of the pressure and duty loads of the machine. Of course, such blow-by is accomplished by using fluid that would otherwise be used to drive or be driven by the pistons to accomplish work. Therefore, in the example just given above, the 4 gallons of fluid per minute used for blow-by lubrication, reduces the volumetric efficiency of the machine.
The invention disclosed below is directed to improving the volumetric efficiency of such elongated-piston machines while, at the same time, assuring (a) appropriate lubrication of the pistons and (b) simplification of the apparatus used to maintain contact between the pistons and the swash-plate.
SUMMARY OF THE INVENTION
The invention is disclosed on various embodiments of hydraulic machines, all of which share a novel combination of simple structural features including elongated pistons reciprocating in a fixed cylinder block, cylinders provided with unique lubrication recesses, and shoes directly attached to each piston (without dog bones) that make sliding contact with a rotating and nutating swash-plate or, preferably, with the nutating-only wobbler portion of a split swash-plate. These simple structural features synergistically result in (a) a remarkable 90% increase in volumetric efficiency and (b) such increased mechanical efficiency that even the drive shafts of machines as large as 12-cubic inch capacity can be easily turned by hand when the machine is fully assembled.
Each disclosed machine can operate as either a pump or a motor. One embodiment has a swash-plate that, while rotating at all times with the drive element of the machine, is fixed at a predetermined inclined angle relative to the axis of the drive element so that the piston move at a maximum predetermined stroke at all times. The swash-plate of the other disclosed machine have inclinations that can be varied throughout a range of angles in a manner well known in the art to control the stroke of the pistons throughout a range of movements up to a maximum in each direction. [However, persons skilled in the art will appreciate that the invention is equally applicable to hydraulic machines with rotating cylinder blocks and swash-plate that do not rotate with the drive element of the machines.]
In each machine according to the invention, each piston is elongated, having an axially cylindrical body portion that preferably is substantially as long as the axial length of the respective cylinder in which it reciprocates. Preferably, each piston also has a spherical head end that, by means of a conventionally pivoted shoe and relatively simple apparatus, is maintained in effective sliding contact with a flat face of the machine's swash-plate. The axial length of each cylindrical piston body is selected to assure minimal lateral displacement of the spherical first end of the piston at all times. Therefore, the preferable piston for this invention is “elongated”. That is, even when each piston is extended to its maximum stroke, that portion of the piston body which is still supported within its respective cylinder is sufficient to assure a minimal lateral displacement of the extended spherical end of the piston at all times during machine operation.
[NOTE: to facilitate explanation of the invention, each piston is described as having an axial cylindrical body portion and a spherical head end, while each respective cylinder has a valve end and an open head portion beyond which the spherical head end of each piston extends at all times. Further, for all preferred embodiments, it is assumed that each disclosed hydraulic machine (e.g., whether motor or pump) is paired with a similar hydraulic machine (e.g., a mating pump or motor) in a well known “closed loop” arrangement (see FIG. 10 ) wherein the high-pressure fluid exiting from the outlet 139 of each pump 110 is directly delivered to the input 36 of the related motor 10 , while the low-pressure fluid exiting from the outlet 37 of each motor 10 is directly delivered to the input 136 of the related pump 110 . As understood in the art, a portion of the fluid in this closed loop system is continually lost to “blow-by” and is collected in a sump; and fluid is automatically delivered from the sump back into the closed loop, by a charge pump, to maintain a predetermined volume of fluid in the closed loop system at all times.]
According to the invention, each cylinder formed within the cylinder blocks of each machine is provided with a respective lubricating channel formed in the cylindrical wall of each cylinder. This lubricating channel is positioned so that at all times during reciprocation of the piston within its respective cylinder, each respective lubricating channel remains almost completely closed by the axial cylindrical body of the piston during its entire stroke. [The movement of fluid in these lubricating channels is discussed in greater detail beginning two paragraphs below.] Preferably, each respective lubricating channel is formed circumferentially and radially transects each cylinder.
Also formed in the fixed cylinder block of each machine are a plurality of further passageways that interconnect each of the just-described lubricating channels. The interconnection of all of the lubricating channels, one to another, forms a single, continuous lubricating passageway in the cylinder block. This continuous lubricating passageway is formed entirely within the cylinder block, preferably transecting each cylinder and being centered circumferentially at substantially the same radial distance as the cylinders are centered about the rotational axis of the drive element.
Special attention is called to the fact that, in the preferred embodiments disclosed, the continuous lubricating passageway just described above is not connected by either fluid “input” or fluid “output” passageways but instead is almost completely closed off by the cylindrical body portions of the pistons at all times during operation of the machine. Therefore, the only source of lubricating fluid supplying this continuous lubricating passageway is a secondary minimal flow of fluid between each of the respective cylindrical walls of each cylinder and the axial cylindrical body of each respective piston. During operation, this lubricating passageway almost instantly fills with an initial minimal flow of high-pressure fluid that enters at the valve end of each cylinder and then passes between the walls of each cylinder and the outer circumference of the body portion of each driven piston. This secondary minimal flow effectively maintains high pressure within the continuous lubricating passageway at all times. If necessary, a plurality of sealing members, each located respectively near the open end of each cylinder, can optionally provide a relatively tight seal for substantially eliminating blow-by between the body portion of each piston and the open head portion of each respective cylinder, thereby allowing the escape of only minimal blow-by from this lubricating passageway past the open end of the cylinders. However, in actual practice it has been found that only a relatively minimal blow-by from the open end of the cylinders moves past the elongated pistons of the invention and, since a small amount of blow-by mist is required for adequate lubrication of the drive shaft bearings, etc., such optional sealing members may not be necessary.
Nonetheless, the lubricating fluid in this closed continuous lubricating passageway moves constantly as the result of the ever-changing pressures in each of the respective cylinders as the pistons reciprocate. That is, as the pressure in each cylinder is reduced to low pressure on the return stroke of each piston, the high pressure fluid in the otherwise closed lubricating passageway is again driven between the walls of each cylinder and the outer circumference of the body of each piston into the valve end of each cylinder experiencing such pressure reduction. However, the lubricating fluid that is driven toward low pressure is not “lost”, i.e., it is not “blow-by” and is in returned to the sump to be replenished into the closed loop hydraulic system by the charge pump. Instead, this low pressure lubricating fluid is immediately returned to the closed loop without requiring the use of a charge pump, and the closed continuous lubricating passageway is immediately replenished by the entrance of a similar flow of high-pressure fluid from the valve end of each cylinder experiencing increased pressure.
The just-described lubricating passageway provides appropriate lubrication for the high-speed reciprocation of the pistons while substantially reducing blow-by. During successful operation of commercial prototypes built according to the invention, blow-by was reduced by 90%. That is, the blow-by experienced by conventional commercial hydraulic machines of comparable specifications generally ranges between 4–5 gallons per minute, while the blow-by experienced by the invention's prototypes ranges between 0.5–0.7 gallons per minute, thereby remarkably increasing the volumetric efficiency of the invention's hydraulic machines.
As indicated above, fixed-cylinder-block hydraulic machines can be built smaller and lighter than conventional rotating block hydraulic machines having similar specifications. As a result of the improved lubrication of the elongated pistons, the disclosed invention makes it possible to use these smaller and lighter designs to meet the high-speed/high-pressure specifications required for automotive use.
Further, special attention is called to the invention's significantly simplified support assemblies for the variable rotating swash-plates of the invention's disclosed hydraulic machines. All of the invention's support assemblies disclosed herein omit dog-bones that normally are mounted between the outer end of each piston and the nutating-only wobbler portion of a conventional rotating/nutating swash-plate. Further, one embodiment also omits the nutating-only wobbler portion of a conventional rotating/nutating swash-plate. In all embodiments, a conventional shoe is mounted directly to the spherical head of each piston and is maintained in effective sliding contact with the flat face portion of the swash-plate by means of a minimal spring bias sufficient to maintain such effective sliding contact in the absence of hydraulic pressure at the valve ends of the pump's cylinders.
Three simplified support mechanisms are disclosed: The first simplified support mechanism comprises a unique hold-down plate assembly biased by a single coil spring positioned circumferentially about the rotational axis of the pump's drive element. The invention's second support mechanism is even simpler, comprising nothing more than a conventional shoe mounted directly to the spherical head of each piston, with the minimal bias being supplied by a plurality of springs, each spring being positioned respectively within the body portion of each respective piston between the body portion of each respective piston and the valve end of each respective cylinder. While the second support mechanism is a little more difficult to assemble than the first, the latter is considerably simpler, lighter, and cheaper to manufacture.
The third of the disclosed simplified support mechanisms is the preferred arrangement. Namely, it includes a traditional split swash-plate, but modified by adding needle bearings to support the nutating-only wobbler portion on the nutating/rotating rotor member. While this third embodiment also includes a unique hold-down plate assembly similar to the first embodiment, this latter hold-down plate is biased by a plurality of springs, each spring being positioned, respectively, circumferentially about the sliding shoe associated with the head of each piston. This third embodiment provides a dramatic change in the dynamics of operation of the sliding shoes, significantly reducing the surface speed of the relative motion between the shoes and the swash-plate and, thereby, resulting in a reduction in wear and costs, and in a significant increase in machine efficiency.
The important changes introduced by this invention provide hydraulic machines that are lighter and smaller than conventional machines having similar specifications. Further, as indicated above, actual testing of working prototypes have proven that this invention provides machines with significantly increased volumetric and mechanical efficiency. In short, the invention disclosed herein provides machines having remarkably greater efficiency while significantly reducing the weight and size of the machines as well as the cost of manufacture and simplifying assembly.
DRAWINGS
FIG. 1 is a partially schematic and cross-sectional view of a hydraulic machine with a fixed cylinder block and a rotating/nutating swash-plate having a fixed angle of inclination, showing features of the invention incorporated in the cylinder block and at the piston/swash-plate interface.
FIG. 2 is a partially schematic and cross-sectional view of the fixed cylinder block of the hydraulic machine of FIG. 1 taken along the plane 2 — 2 with parts being omitted for clarity.
FIG. 3 is a partially schematic and cross-sectional view of a hydraulic machine with a fixed cylinder block and a rotating/nutating swash-plate having a variable angle of inclination, again showing features of the invention incorporated in the cylinder block and at the piston/swash-plate interface.
FIGS. 4A and 4B are partially schematic and cross-sectional views of the swash-plate and piston shoe hold-down assembly disclosed in FIGS. 1 and 3 , with parts removed for clarity, showing relative positions of the head ends of the pistons, shoes, and special washers, as well as the spring-biased hold-down element that biases each sliding shoe against the flat face of the swash-plate when the swash plate is inclined at +25°, the view in FIG. 4A being taken in the plane 4 A— 4 A of FIG. 3 in the direction of the arrows, while the view in FIG. 4B is taken in the plane 4 B— 4 B of FIG. 4A .
FIGS. 5A and 5B , 6 A and 6 B, and 7 A and 7 B are views of the same parts illustrated in FIGS. 4A and 4B when the swash-plate is inclined, respectively, at +15°, 0°, and −25°, the respective views in FIGS. 5B , 6 B, and 7 B being taken in the respective planes 5 B— 5 B, 6 B— 6 B, and 7 B— 7 B of FIGS. 5A , 6 A and 7 A.
FIG. 8 is an enlarged, partial, schematic and cross-sectional view of only a single cylinder and piston for another hydraulic machine similar to those shown in FIGS. 1 and 3 but showing a more simplified second embodiment of a spring-biased hold-down assembly for the invention's piston shoes.
FIG. 9 is a partially schematic and cross-sectional view of another embodiment of the invention, showing a portion of another hydraulic machine with a fixed cylinder block substantially identical to that disclosed in FIG. 3 but including an improved version of a conventional split swash-plate with a variable angle of inclination and having a nutating-only wobbler mounted on a rotating/nutating rotor, this view omitting the valve end of the cylinder block and portions of the housing as well as other parts for clarity.
FIG. 10 is a view of a prior art “closed loop” arrangement of two hydraulic machines.
DETAILED DESCRIPTION
The operation of hydraulic machines of the type to which the invention may be added is well known. Therefore, such operation will not be described in detail. As indicated above, it can be assumed that each disclosed machine is connected in a well known “closed loop” hydraulic system with an appropriately mated pump or motor.
Hydraulic Motor
Referring to FIG. 1 , hydraulic motor 10 includes a fixed cylinder block 12 having a plurality of cylinders 14 (only one shown) in which a respective plurality of mating pistons 16 reciprocate between the retracted position of piston 16 and the extended position of piston 16 ′. Each piston has a spherical head 18 that is mounted on a neck 20 at one end of an elongated axial cylindrical body portion 22 that, in the preferred embodiments shown, is substantially as long as the length of each respective cylinder 14 .
Each spherical end 18 fits within a respective shoe 24 that slides over a flat face 26 formed on the surface of a rotor 28 that, in turn, is fixed to a drive element, namely, shaft 30 of the machine. Shaft 30 is supported on bearings within a bore 31 in the center of cylinder block 12 . Flat face 26 of rotor 28 is inclined at a predetermined maximum angle (e.g., 25°) to the axis 32 of drive shaft 30 .
A modular valve assembly 33 , which is bolted as a cap on the left end of cylinder block 12 , includes a plurality of spool valves 34 (only one shown) that regulates the delivery of fluid into and out the cylinders 14 . As indicated above, each of the machines disclosed can be operated as either a pump or as a motor. For this description of a preferred embodiment, the fixed-angle swash-plate machine shown in FIG. 1 is being operated as a motor. Therefore, during the first half of each revolution of drive shaft 30 , high pressure fluid from inlet 36 enters the valve end of each respective cylinder 14 through a port 37 to drive each respective piston from its retracted position to its fully extended position; and during the second half of each revolution, lower pressure fluid is withdrawn from each respective cylinder through port 37 and fluid outlet 39 as each piston returns to its fully retracted position.
In a manner well known in the art: fluid inlet 36 and outlet 39 are preferably connected through appropriate “closed loop” piping to a matching hydraulic pump so that, at all times, fluid pressure biases spherical ends 18 and respective shoes 24 against flat surface 26 . The serial extension and retraction of each respective piston causes rotor 28 to rotate, thereby driving shaft 30 .
Also, as well known in the art, motor 10 is connected in a closed loop of circulating hydraulic fluid with a mating hydraulic pump (e.g., pump 110 shown in FIG. 3 and discussed below); and flat face 26 is fixed at the maximum angle of inclination so that, when the flow rate of hydraulic fluid being circulated in the closed loop through inlet 36 and outlet 39 is relatively small, pistons 16 reciprocate relatively slowly, resulting in a relatively slow rotation of drive shaft 30 .
However, as the flow rates of fluid circulation in the closed loop increase, the reciprocation of the pistons increases accordingly, and so does the speed of rotation of drive shaft 30 . When operated at automotive speeds or pressures (e.g., up to 4000 rpm or 4000 psi), lubrication of the pistons becomes critical, and blow-by losses can also greatly increase. Cylinder block 12 is modified by the invention to address such lubrication needs and to reduce such blow-by losses.
Referring now to both FIGS. 1 and 2 , the cylindrical wall of each cylinder 14 is transected radially by a respective lubricating channel 40 formed circumferentially therein. A plurality of passageways 42 interconnect all lubricating channels 40 to form a continuous lubricating passageway in cylinder block 12 . Each respective lubricating channel 40 is substantially closed by the axial cylindrical body 22 of each respective piston 16 during the entire stroke of each piston. That is, the outer circumference of each cylindrical body 22 acts as a wall that encloses each respective lubricating channel 40 at all times. Thus, even when pistons 16 are reciprocating through maximum strokes, the continuous lubricating passageway interconnecting all lubricating channels 40 remains substantially closed off. Continuous lubricating passageway 40 , 42 is simply and economically formed within cylinder block 12 as can be best appreciated from the schematic illustration in FIG. 2 in which the relative size of the fluid channels and connecting passageways and has been exaggerated for clarification.
During operation of hydraulic motor 10 , all interconnected lubricating channels 40 are filled almost instantly by a minimal flow of high-pressure fluid from inlet 36 entering each cylinder 14 through port 37 and being forced between the walls of the cylinders and the outer circumference of each piston 16 . Loss of lubricating fluid from each lubricating channel 40 is restricted by a surrounding seal 44 located near the open end of each cylinder 14 . Nonetheless, the lubricating fluid in this closed continuous lubricating passageway of lubricating channels 40 flows moderately but continuously as the result of a continuous minimal flow of fluid between each of the respective cylindrical walls of each cylinder and the axial cylindrical body of each respective piston in response to piston motion and to the changing pressures in each half-cycle of rotation of drive shaft 30 as the pistons reciprocate. As the pressure in each cylinder 14 is reduced to low pressure on the return stroke of each piston 16 , the higher pressure fluid in otherwise closed lubricating passageway 40 , 42 is again driven between the walls of each cylinder 14 and the outer circumference of body portion 22 of each piston 16 into the valve end of each cylinder 14 experiencing such pressure reduction.
However, special attention of persons skilled in the art is called to the fact that this just-mentioned minimal flow of fluid back into cylinder 14 is not “lost”. Instead, it is immediately returned to the well known closed hydraulic fluid loop that interconnects the pump and motor. Further, this minimal flow of fluid does not return to a sump and, therefore, does not have to be replenished into the closed loop hydraulic system by a charge pump. Finally, closed continuous lubricating passageway 40 , 42 is immediately replenished by the entrance of a similar minimal flow of high-pressure fluid from the valve end of each cylinder experiencing increased pressure.
As mentioned above, there is minimal blow-by loss from closed continuous lubricating passageway 42 that interconnects all lubricating channels 40 . That is, there is still some minimal fluid flow that leaks from this closed continuous lubricating passageway past the seals 44 at the end of each cylinder 14 . However, any such minimal blow-by is instantly replenished by a similar minimal flow of high pressure fluids entering around the opposite end of each piston 16 .
The just described lubrication arrangement is not only remarkably simple, and it also permits a similar simplification of the pinion/swash-plate interface apparatus of the hydraulic machine to further reduce the cost of manufacture and operation.
To complete the description of hydraulic motor 10 , the pinion/swash-plate interface apparatus shown in FIG. 1 comprises only (a) rotor 28 mounted on drive shaft 30 using conventional needle and thrust bearings and (b) a simple spring-biased hold-down assembly for maintaining piston shoes 24 in constant contact with the rotating and nutating flat surface 26 of rotor 28 . [Note: Three embodiments of the invention's simplified pinion/swash-plate interface assemblies are disclosed. While only the first of these hold-down assemblies is shown in combination with the motor and pump illustrated in FIGS. 1 and 3 , each is described in greater detail in a separate section below.]
The first embodiment of the invention's hold-down assembly, as shown in FIG. 1 , includes a coil spring 50 that is positioned about shaft 30 and received in an appropriate crevice 52 formed in cylinder block 12 circumferentially about axis 32 . Spring 50 biases a hold-down element 54 that is also positioned circumferentially about shaft 30 and axis 32 . Hold-down element 54 is provided with a plurality of openings, each of which surrounds the neck 20 of a respective piston 16 . A respective special washer 56 is positioned between hold-down element 54 and each piston shoe 24 . Each washer 56 has an extension 58 that contacts the outer circumference of a respective shoe 24 to maintain the shoe in contact with flat face 26 of rotor 28 at all times.
Just described hydraulic motor 10 , with its remarkable simplification of both lubrication and the piston/swash-plate interface, is efficient, easy to manufacture, and economical to operate.
Variable Hydraulic Pump
A second preferred embodiment of a hydraulic machine in accordance with the invention is illustrated in FIG. 3 . A variable hydraulic pump 110 includes a modular fixed cylinder block 112 which is identical to cylinder block 12 of hydraulic motor 10 shown in FIG. 1 and described above. Cylinder block 112 has a plurality of cylinders 114 (only one shown) in which a respective plurality of mating pistons 116 reciprocate between the retracted position of piston 116 and variable extended positions (the maximum extension being shown in the position of piston 116 ′). Each piston has a spherical head 118 that is mounted on a neck 120 at one end of an elongated axial cylindrical body portion 122 that, in the embodiment shown, is substantially as long as the length of each respective cylinder 114 . Each spherical piston head 118 fits within a respective shoe 124 that slides over a flat face 126 formed on the surface of a rotor 128 that, as will be discussed in greater detail below, is pivotally attached to a drive element, namely, shaft 130 that is supported on bearings within a bore in the center of cylinder block 112 .
In a manner similar to that explained above in regard to hydraulic motor 10 , variable pump 110 also is provided with a modular valve assembly 133 that is bolted as a cap on the left end of modular cylinder block 112 and, similarly, includes a plurality of spool valves 134 (only one shown) that regulate the delivery of fluid into and out cylinders 114 .
As indicated above, each of the machines disclosed can be operated as either a pump or as a motor. For the description of this preferred embodiment, the variable-angle swash-plate machine 110 shown in FIG. 3 is being operated as a pump, and drive shaft 130 is driven by a prime mover (not shown), e.g., the engine of a vehicle. Therefore, during the one half of each revolution of drive shaft 130 , lower pressure fluid is drawn into each respective cylinder 114 entering a port 137 from a “closed loop” of circulating hydraulic fluid through inlet 136 as each piston 116 is moved to an extended position; and during the next half of each revolution, the driving of each respective piston 116 back to its fully retracted position directs high pressure fluid from port 137 into the closed hydraulic loop through outlet 139 . The high pressure fluid is then delivered through appropriate closed loop piping (not shown) to a mating hydraulic pump, e.g., pump 12 discussed above, causing the pistons of the mating pump to move at a speed that varies with the volume (gallons per minute) of high pressure fluid being delivered in a manner well known in the art.
Once again referring to modular cylinder block 112 , it, is constructed identical to cylinder block 12 which has already been described. That is, the cylindrical wall of each cylinder 114 is transected radially by a respective lubricating channel 140 formed circumferentially therein. A plurality of passageways 142 interconnect all lubricating channels 140 to form a continuous lubricating passageway in cylinder block 112 . A cross-section of cylinder block 112 taken in the plane 2 — 2 looks exactly as the cross-sectional view of cylinder block 12 in FIG. 2 .
In effect, almost all of the discussion above relating to the invention's continuous lubricating passageway 40 , 42 with reference to the apparatus of hydraulic motor 10 shown in FIGS. 1 and 2 , applies equally to the operation of continuous lubricating passageway 140 , 142 in cylinder block 112 of hydraulic pump 110 shown in FIG. 3 , including the fairly extreme minimization of loss of lubricating fluid from each lubricating channel 140 by optionally including a surrounding seal 144 located near the open end of each cylinder 114 . Similarly, the flow of lubricating fluid in closed continuous lubricating passageway 140 , 142 is moderate but continuous as the result of a secondary minimal fluid flow in response to piston motion and to the changing pressures in each half-cycle of rotation of drive shaft 130 as the pistons reciprocate. Of course, as is different in pump 110 , lower fluid pressure is present in each cylinder 114 when each piston 116 is moving to an extended position, while the source of the high pressure fluid that is forced between the walls of the cylinders and the outer circumference of each piston 116 occurs as each piston 116 is being driven from its extended position to its fully retracted position by the rotation of drive shaft 130 by the prime mover (not shown).
However, once again special attention of persons skilled in the art is called to the fact that this just-mentioned secondary minimal fluid flow back into each cylinder 114 is not “lost”. Instead, it is immediately returned to the well known closed hydraulic fluid loop that interconnects the pump and motor. That is, this secondary fluid flow does not return to a sump and, therefore, does not have to be replenished into the closed loop hydraulic system by a charge pump. Also, while there may be a minimal blow-by that leaks from closed continuous lubricating passageway 140 , 142 past the seals 144 at the end of each cylinder 114 , any such minimal blow-by is instantly replenished by a similar minimal fluid flow entering around the opposite end of each piston 116 experiencing increased pressure.
As discussed in the preamble above, the invention permits the machine's swash-plate apparatus to be simplified (a) by the omission of the dog-bones that normally are mounted between the outer end of each piston and a nutating-only wobbler portion of a conventional rotating/nutating swash-plate and (b) in the embodiments illustrated in FIGS. 1 and 3 , by the omission of the wobbler portion itself as well as the apparatus conventionally required for mounting the non-rotating wobbler to the rotating/nutating rotor portion of the swash-plate.
Still referring to FIG. 3 , rotor 128 of pump 110 is pivotally mounted to drive shaft 130 about an axis 129 that is perpendicular to axis 132 . Therefore, while rotor 128 rotates with drive shaft 130 , its angle of inclination relative to axis 130 can be varied from 0° (i.e., perpendicular) to ±25°. In FIG. 3 , rotor 128 is inclined at +25°. This variable inclination is controlled as follows: The pivoting of rotor 128 about axis 129 is determined by the position of a sliding collar 180 that surrounds drive shaft 130 , and is movable axially relative thereto. A control-link 182 connects collar 180 with rotor 128 so that movement of collar 180 axially over the surface of drive shaft 130 causes rotor 128 to pivot about axis 129 . For instance, as collar 128 is moved to the right in FIG. 3 , the inclination of rotor 128 varies throughout a continuum from the +25° inclination shown, back to 0° (i.e., perpendicular), and then to −25°.
The axial movement of collar 180 is controlled by the fingers 184 of a yoke 186 as yoke 186 is rotated about the axis of a yoke shaft 190 by articulation of a yoke control arm 188 . Yoke 186 is actuated by a conventional linear servo-mechanism (not shown) connected to the bottom of yoke arm 188 . In this preferred embodiment, while the remainder of the elements of yoke 186 are all enclosed within a modular swash-plate housing 192 and yoke shaft 190 is supported in bearings fixed to housing 192 , yoke control arm 188 is positioned external of housing 192 .
It will also be noted that swash-plate rotor 128 is balanced by a shadow-link 194 that is substantially identical to control-link 182 and is similarly connected to collar 180 but at a location on exactly the opposite side of collar 180 .
Piston Shoe Hold-Down Assemblies
Fluid pressure constantly biases pistons 116 in the direction of rotor 128 , and the illustrated conventional thrust plate assembly is provided to carry that load. However, at the speeds of operation required for automotive use (e.g., 4000 rpm) additional bias loading is necessary to assure constant contact between piston shoes 124 and flat surface 126 of rotor 128 . In view of the invention's omission of conventional dog-bones, the variable hydraulic machines of this invention provide such additional bias by using one of three simple spring-biased hold-down assemblies, the first being similar to that already briefly described above in regard to hydraulic motor 10 in FIG. 1 .
(a) Hold-Down Assembly with Single-Spring Bias
The following description of the invention's first embodiment for a hold-down assembly continues to refer to FIG. 3 , but reference is now also made (a) to FIG. 4A , which shows an enlarged view taken in the plane 4 A— 4 A of FIG. 3 when viewed in the direction of the arrows, and (b) to FIG. 4B , which shows an enlargement of the same view of shown in FIG. 1 with parts removed for clarity.
The hold-down assembly for pump 110 includes a coil spring 150 that is positioned about shaft 130 and received in an appropriate crevice 152 formed in cylinder block 112 circumferentially about axis 132 . Coil spring 150 biases a hold-down element 154 that is also positioned circumferentially about shaft 130 and axis 132 . Hold-down element 154 is provided with a plurality of circular openings 160 , each of which surrounds the neck 120 of a respective piston 116 . A plurality of special washers 156 are positioned, respectively, between hold-down element 154 and each piston shoe 124 . Each washer 156 has an extension 158 that contacts the outer circumference of a respective shoe 124 to maintain the shoe in contact with flat face 126 of rotor 128 at all times.
The positions of the just-described parts of the swash-plate and piston shoe hold-down assembly change relative to each other as the inclinations of rotor 128 is altered during machine operation. These changes in relative position are illustrated at various inclinations of rotor 128 , namely, at, +25°, in FIGS. 4A and 4B ; at +15° in FIGS. 5A and 5B ; at 0° in FIGS. 6A and 6B ; and at −25°, in FIGS. 7A and 7B . [NOTE: Persons skilled in the art will appreciate that each piston shoe 124 has a conventional pressure-balancing cavity centered on the flat surface of shoe 124 that contacts flat face 126 of rotor 128 , and that each respective shoe cavity is connected through an appropriate shoe channel 162 and piston channel 164 to assure that fluid pressure present at the shoe/rotor interface is equivalent at all times with fluid pressure at the head of each piston 116 . Since piston channel 164 passes through the center of spherical head 118 of each piston 116 , the position of channel 164 can be used to facilitate appreciation of the relative movements of the various parts of the hold-down assembly.]
Referring to the relative position of these parts at the 0° inclination shown in FIGS. 6A and 6B , each piston channel 164 (at the center of each spherical head 118 of each piston 116 ) has the same radial position relative to each respective circular opening 160 in hold-down element 154 . As can be seen from the views in the other illustrated inclinations of swash-plate rotor 128 , at all inclinations other than 0°, the relative radial position of each piston channel 164 is different for each opening 160 , and the relative positions of each special washer 156 is also different.
It must be appreciated that, at each of these illustrated swash-plate inclinations, the different relative positions at each of the nine openings 160 are themselves constantly-changing as rotor 128 rotates and nutates through one complete revolution at each of these inclinations. For instance, at the 25° inclination shown in FIG. 4A , if during each revolution of rotor 128 , one were to watch the movement occurring through only the opening 160 at the top (i.e., at 12:00 o'clock) of hold-down element 154 , the relative position of the parts viewed in the top opening 160 would serially change to match the relative positions shown in each of the other eight openings 160 .
That is, at inclinations other than 0° (e.g., at −25° shown in FIG. 7A ), during each revolution of rotor 128 , each special washer 156 slips over the surface of hold-down element 154 as, simultaneously, each shoe 124 slips over the flat face 126 of rotor 128 ; and each of these parts changes relative to its own opening 160 through each of the various positions that can be seen in each of the other eight openings 160 . These relative motions are largest at ±25° and each follows a cyclical path (that appears to trace a lemniscate, i.e., a “figure-eight”) that varies in size with the angular inclinations of swash-plate rotor 128 and the horizontal position of each piston 116 in fixed cylinder block 112 .
Therefore, to assure proper contact between each respective shoe 124 and flat surface 126 of rotor 128 , in preferred embodiments a size is selected for the boundaries of each opening 160 so that the borders of opening 160 remain in contact with more than one-half of the surface of each special washer 156 at all times during each revolution of rotor 128 and for all inclinations of rotor 128 , as can be seen from the relative positions of special washers 156 and the borders of each of the openings 160 in each of the drawings from FIG. 4A through FIG. 7A . As can be seen from the drawings, a circular border is preferred for each opening 160 .
(b) Hold-Down Assembly with Multiple-Spring Piston Bias
The second embodiment of the invention's hold-down assembly, while slightly more difficult to assemble, is considerably simpler and less expensive. This second embodiment is shown schematically in FIG. 8 in an enlarged, partial, and cross-sectional view of a single piston of a further hydraulic machine 210 according to the invention. Piston 216 is positioned in modular fixed cylinder block 212 within cylinder 214 , the latter being transected radially by a respective lubricating channel 40 ″ formed circumferentially therein. In the same manner as described in relation to the other hydraulic machines already detailed above, each lubricating channel 40 ″ is interconnected with similar channels in the machine's other cylinders to form a continuous lubricating passageway in cylinder block 212 ; and, similarly, an optional surrounding seal 44 ″ may be located near the open end of each cylinder 214 to further minimize the loss of lubricating fluid from each lubricating channel 40 ″.
The only difference between fixed cylinder block 212 and the modular cylinder blocks disclosed in FIGS. 1 and 3 is that fixed cylinder block 212 includes neither a large axially circumferential coil spring nor an axially circumferential crevice for holding same.
While not shown, the modular fixed cylinder block 212 of hydraulic machine 210 can be connected to either a modular fixed-angle swash-plate assembly (as shown in FIG. 1 ) or a modular variable-angle swash-plate assembly (as shown in FIG. 3 ), but in either case, hydraulic machine 210 provides a much simpler hold-down assembly. Namely, the hold-down assembly of this embodiment comprises only a respective conventional piston shoe 224 for each piston 216 in combination with only a respective coil spring 250 , the latter also being associated with each respective piston 216 .
Each piston shoe 224 is similar to the conventional shoes shown in the first hold-down assembly just discussed above and, similarly, is mounted on the spherical head 218 of piston 216 to slide over the flat face 226 formed on the surface of the machine's swash-plate rotor 228 in a manner similar to that explained above. Each coil spring 250 is, respectively, seated circumferentially about hydraulic valve port 237 at the valve end of each respective cylinder 214 and positioned within the body portion of each respective piston 216 .
Again, in the manner just explained above, each shoe 224 slips over flat face 226 of rotor 228 with a lemniscate motion that varies in size with the horizontal position of each piston 216 and the inclination of rotor 228 relative to axis 230 . During normal operation of hydraulic machine 210 , shoes 224 are maintained in contact with flat face 226 of the swash-plate by hydraulic pressure. Therefore, the spring bias provided by coil springs 250 is only minimal but still sufficient to maintain effective sliding contact between each shoe 224 and flat face 226 in the absence of hydraulic pressure at the valve end of each respective cylinder 214 .
It has been found that the just-described minimal bias of springs 250 not only facilitates-assembly but is also sufficient to prevent entrapment of tiny dirt and metal detritus encountered during assembly and occasioned by wear. Further, special attention is again called to the fact that this second embodiment provides this necessary function with only a few very inexpensive parts.
(c) Hold-Down Assembly with Multiple-Spring Shoe Bias
Referring to FIG. 9 , a preferred hold-down assembly is disclosed in a preferred hydraulic machine, namely, pump 310 that, while being substantially similar to pump 110 illustrated in FIG. 3 and described in detail above, includes an improved conventional split swash-plate arrangement.
As with the other hydraulic machines described above, a plurality of pistons 316 , each including a respective sliding shoe 324 , reciprocate in respective cylinders 314 formed in cylinder block 312 that is identical to cylinder blocks 12 and 112 as described above. Each shoe 324 slides on the flat face 326 formed on a wobbler 327 that is mounted on a mating rotor 328 by appropriate needle bearings 372 , 374 that permit wobbler 327 to nutate without rotation while rotor 328 both nutates and rotates in the manner well known in the art.
It will be apparent to those skilled in the art, that the inclination of wobbler 327 and rotor 328 about axis 329 is controlled by the position of a sliding collar 380 , a control link 382 and a balancing shadow link 394 in exactly the same manner as described above in regard to pump 110 illustrated in FIG. 3 .
Shoes 324 are held down by a hold-down assembly substantially identical to the first hold-down assembly described in detail in sub-section (a) above. However, in this preferred embodiment, the large single coil spring 150 is replaced by a plurality of smaller individual coil springs as follows:
A hold-down plate 354 is fixed to wobbler 327 and is otherwise identical to hold-down element 154 described in detail above with reference to FIGS. 4–7 . Similarly, each shoe 324 receives the circumferential extension of a respective special washer 356 that is identical to each special washer 156 as described in detail above, and the neck of each piston 316 is positioned within one of a corresponding plurality of respective openings 360 formed through hold-down plate 354 , all exactly similar to the apparatus of the first hold-down assembly described in detail in sub-section (a) above.
While wobbler 327 does not rotate with rotor 328 , the nutational movement of wobbler 327 is identical to the nutational movement of rotor 328 and, therefore, the relative motions between shoes 324 and the flat surface 326 of wobbler 327 are also identical to that described in detail in sub-section (a) above.
In this embodiment, a plurality of individual coil springs 350 provides the minimal spring bias that is necessary, in the absence of hydraulic pressure at the valve end of each cylinder 314 , to maintain effective sliding contact between each shoe 324 and flat face 326 of wobbler 327 . Each coil spring 350 is positioned circumferentially about each shoe 324 , being captured between each special washer 356 and a collar formed just above the bottom of each shoe 324 .
The preferred embodiment that has just been described provides the same remarkable improvement in volumetric efficiency with full lubrication as the other embodiments disclosed. Further, it also provides a dramatic change in the dynamics of the operation of the sliding shoes, greatly improving efficiency and significantly reducing wear and the concomitant costs related to such wear.
The invention's hydraulic machines all provide remarkably improved volumetric efficiencies with effective lubrication as well as piston/swash-plate interface assemblies that provide further economies by being relatively simple and inexpensive to manufacture and by reducing the number of parts required for efficient operation.
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Smaller and lighter hydraulic pump/motors provide remarkably improved volumetric efficiency with pistons having body portions substantially as long as the axial length of the respective cylinders in which they reciprocate. A plurality of respective lubricating channels form a single, continuous lubricating passageway entirely within the cylinder block and not connected by either fluid “input” or fluid “output” passageways, being replenished solely by a minimal flow of fluid to and from the valve end of each cylinder and passing between each respective cylindrical wall of each cylinder and the axial cylindrical body of each respective piston. Several embodiments are disclosed in combination with various spring-biased hold-down assemblies. The preferred embodiment included a fixed cylinder block, a roller bearing mounting between the wobbler and rotor of a split-swash plate, with piston shoes contacting the wobbler directly without any intermediary apparatus.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a Continuation of U.S. patent application Ser. No. 13/106,640, filed May 12, 2011, now pending, which is a non-provisional of, and claims benefit of priority under 35 U.S.C. 119(e) from, U.S. Provisional Patent Application No. 61/331,103, filed May 4, 2010, and which claims priority under 35 U.S.C. 371 from PCT/IB11/01026, filed May 13, 2011, the entirety of which are expressly incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates to the field of heatsinks or items that transfer heat between a concentrated source or sink and a fluid.
BACKGROUND OF THE INVENTION
[0003] A heat sink is a term for a component or assembly that transfers heat generated within a solid material to a fluid medium, such as air or a liquid. A heat sink is typically physically designed to increase the surface area in contact with the cooling fluid surrounding it, such as the air. Approach air velocity, choice of material, fin (or other protrusion) design and surface treatment are some of the design factors which influence the thermal resistance, i.e. thermal performance, of a heat sink.
[0004] A heat sink transfers thermal energy from a higher temperature to a lower temperature fluid medium. The fluid medium is frequently air, but can also be water or in the case of heat exchangers, refrigerants and oil. Fourier's law of heat conduction, simplified to a one-dimensional form in the x-direction, shows that when there is a temperature gradient in a body, heat will be transferred from the higher temperature region to the lower temperature region. The rate at which heat is transferred by conduction, q k , is proportional to the product of the temperature gradient and the cross-sectional area through which heat is transferred:
[0000]
q
k
=
-
kA
T
x
(
1
)
[0000] where q k is the rate of conduction, k is a constant which depends on the materials that are involved, A is the surface area through which the heat must pass, and dT/dx is the rate of change of temperature with respect to distance (for simplicity, the equation is written in one dimension). Thus, according to Fourier's law (which is not the only consideration by any means), heatsinks benefit from having a large surface area exposed to the medium into which the heat is to be transferred.
[0005] Consider a heat sink in a duct, where air flows through the duct, and the heat sink base is higher in temperature than the air. Assuming conservation of energy, for steady-state conditions, and applying Newton's law of cooling, gives the following set of equations.
[0000]
Q
.
=
m
.
c
p
,
in
(
T
air
,
out
-
T
air
,
in
)
(
2
)
Q
.
=
T
hs
-
T
air
,
av
R
hs
(
3
)
T
air
,
av
=
T
air
,
out
+
T
air
,
in
2
(
4
)
[0006] Using the mean air temperature is an assumption that is valid for relatively short heat sinks. When compact heat exchangers are calculated, the logarithmic mean air temperature is used {dot over (m)} the air mass flow rate in kg/s.
[0007] The above equations show that when the air flow through the heat sink decreases, this results in an increase in the average air temperature. This in turn increases the heat sink base temperature. And additionally, the thermal resistance of the heat sink will also increase. The net result is a higher heat sink base temperature. The inlet air temperature relates strongly with the heat sink base temperature. Therefore, if there is no air or fluid flow around the heat sink, the energy dissipated to the air cannot be transferred to the ambient air. Therefore, the heat sink functions poorly.
[0008] Other examples of situations in which a heat sink has impaired efficiency: Pin fins have a lot of surface area, but the pins are so close together that air has a hard time flowing through them; Aligning a heat sink so that the fins are not in the direction of flow; Aligning the fins horizontally for a natural convection heat sink. Whilst a heat sink is stationary and there are no centrifugal forces and artificial gravity, air that is warmer than the ambient temperature always flows upward, given essentially-still-air surroundings; this is convective cooling.
[0009] The most common heat sink material is aluminum. Chemically pure aluminum is not used in the manufacture of heat sinks, but rather aluminum alloys. Aluminum alloy 1050A has one of the higher thermal conductivity values at 229 W/m·K. However, it is not recommended for machining, since it is a relatively soft material. Aluminum alloys 6061 and 6063 are the more commonly used aluminum alloys, with thermal conductivity values of 166 and 201 W/m·K, respectively. The aforementioned values are dependent on the temper of the alloy.
[0010] Copper is also used since it has around twice the conductivity of aluminum, but is three times as heavy as aluminum. Copper is also around four to six times more expensive than aluminum, but this is market dependent. Aluminum has the added advantage that it is able to be extruded, while copper cannot. Copper heat sinks are machined and skived. Another method of manufacture is to solder the fins into the heat sink base.
[0011] Another heat sink material that can be used is diamond. With a value of 2000 W/mK it exceeds that of copper by a factor of five. In contrast to metals, where heat is conducted by delocalized electrons, lattice vibrations are responsible for diamond's very high thermal conductivity. For thermal management applications, the outstanding thermal conductivity and diffusivity of diamond is an essential. CVD diamond may be used as a sub-mount for high-power integrated circuits and laser diodes.
[0012] Composite materials can be used. Examples are a copper-tungsten pseudoalloy, AlSiC (silicon carbide in aluminum matrix), Dymalloy (diamond in copper-silver alloy matrix), and E-Material (beryllium oxide in beryllium matrix). Such materials are often used as substrates for chips, as their thermal expansion coefficient can be matched to ceramics and semiconductors.
[0013] Fin efficiency is one of the parameters which makes a higher thermal conductivity material important. A fin of a heat sink may be considered to be a flat plate with heat flowing in one end and being dissipated into the surrounding fluid as it travels to the other. As heat flows through the fin, the combination of the thermal resistance of the heat sink impeding the flow and the heat lost due to convection, the temperature of the fin and, therefore, the heat transfer to the fluid, will decrease from the base to the end of the fin. This factor is called the fin efficiency and is defined as the actual heat transferred by the fin, divided by the heat transfer were the fin to be isothermal (hypothetically the fin having infinite thermal conductivity). Equations 5 and 6 are applicable for straight fins.
[0000]
η
f
=
tanh
(
mL
c
)
mL
c
(
5
)
mL
c
=
2
h
f
kt
f
L
f
(
6
)
[0014] Where:
h f is the convection coefficient of the fin Air: 10 to 100 W/(m 2 K) Water: 500 to 10,000 W/(m 2 K) k is the thermal conductivity of the fin material Aluminum: 120 to 240 W/(m·K) L f is the fin height (m) t f is the fin thickness (m)
[0022] Another parameter that concerns the thermal conductivity of the heat sink material is spreading resistance. Spreading resistance occurs when thermal energy is transferred from a small area to a larger area in a substance with finite thermal conductivity. In a heat sink, this means that heat does not distribute uniformly through the heat sink base. The spreading resistance phenomenon is shown by how the heat travels from the heat source location and causes a large temperature gradient between the heat source and the edges of the heat sink. This means that some fins are at a lower temperature than if the heat source were uniform across the base of the heat sink. This non-uniformity increases the heat sink's effective thermal resistance.
[0023] A pin fin heat sink is a heat sink that has pins that extend from its base. The pins can be, for example, cylindrical, elliptical or square. A second type of heat sink fin arrangement is the straight fin. These run the entire length of the heat sink. A variation on the straight fin heat sink is a cross cut heat sink. A straight fin heat sink is cut at regular intervals but at a coarser pitch than a pin fin type.
[0024] In general, the more surface area a heat sink has, the better it works. However, this is not always true. The concept of a pin fin heat sink is to try to pack as much surface area into a given volume as possible. As well, it works well in any orientation. Kordyban has compared the performance of a pin fin and a straight fin heat sink of similar dimensions. Although the pin fin has 194 cm 2 surface area while the straight fin has 58 cm 2 , the temperature difference between the heat sink base and the ambient air for the pin fin is 50° C. For the straight fin it was 44° C. or 6° C. better than the pin fin. Pin fin heat sink performance is significantly better than straight fins when used in their intended application where the fluid flows axially along the pins rather than only tangentially across the pins.
[0025] Another configuration is the flared fin heat sink; its fins are not parallel to each other, but rather diverge with increasing distance from the base. Flaring the fins decreases flow resistance and makes more air go through the heat sink fin channel; otherwise, more air would bypass the fins. Slanting them keeps the overall dimensions the same, but offers longer fins. Forghan, et al. have published data on tests conducted on pin fin, straight fin and flared fin heat sinks. They found that for low approach air velocity, typically around 1 m/s, the thermal performance is at least 20% better than straight fin heat sinks. Lasance and Eggink also found that for the bypass configurations that they tested, the flared heat sink performed better than the other heat sinks tested.
[0026] The heat transfer from the heatsink is mediated by two effects: conduction via the coolant, and thermal radiation. The surface of the heatsink influences its emissivity; shiny metal absorbs and radiates only a small amount of heat, while matte black radiates highly. In coolant-mediated heat transfer, the contribution of radiation is generally small. A layer of coating on the heatsink can then be counterproductive, as its thermal resistance can impair heat flow from the fins to the coolant. Finned heatsinks with convective or forced flow will not benefit significantly from being colored. In situations with significant contribution of radiative cooling, e.g. in case of a flat non-finned panel acting as a heatsink with low airflow, the heatsink surface finish can play an important role. Matte-black surfaces will radiate much more efficiently than shiny bare metal. The importance of radiative vs. coolant-mediated heat transfer increases in situations with low ambient air pressure (e.g. high-altitude operations) or in vacuum (e.g. satellites in space).
[0027] Fourier, J. B., 1822, Theorie analytique de la chaleur, Paris; Freeman, A., 1955, translation, Dover Publications, Inc, N.Y.
[0028] Kordyban, T., 1998, Hot air rises and heat sinks—Everything you know about cooling electronics is wrong, ASME Press, N.Y.
[0029] Anon, Unknown, “Heat sink selection”, Mechanical engineering department, San Jose State University [27 Jan. 2010].
[0000] www.engr.sjsu.edu/ndej ong/ME%20146% 20files/Heat% 20Sink.pptwww.engr.sjsu.edu/ndejong/ME%20146%20files/Heat%20Sink.ppt
[0030] Sergent, J. and Krum, A., 1998, Thermal management handbook for electronic assemblies, First Edition, McGraw-Hill.
[0031] Incropera, F. P. and DeWitt, D. P., 1985, Introduction to heat transfer, John Wiley and sons, N.Y.
[0032] Forghan, F., Goldthwaite, D., Ulinski, M., Metghalchi, M., 2001, Experimental and Theoretical Investigation of Thermal Performance of Heat Sinks, ISME May.
[0033] Lasance, C. J. M and Eggink, H. J., 2001, A Method to Rank Heat Sinks in Practice: The Heat Sink Performance Tester, 21st IEEE SEMI-THERM Symposium.
[0034] ludens.cl/Electron/Thermal.html
[0035] Lienard, J. H., IV & V, 2004, A Heat Transfer Textbook, Third edition, MIT
[0036] Saint-Gobain, 2004, “Thermal management solutions for electronic equipment” 22 Jul. 2008 www.fff.saint-gobain.com/Media/Documents/50000000000000001036/ThermaCool%20Brochure.pdf
[0037] Jeggels, Y. U., Dobson, R. T., Jeggels, D. H., Comparison of the cooling performance between heat pipe and aluminium conductors for electronic equipment enclosures, Proceedings of the 14th International Heat Pipe Conference, Florianópolis, Brazil, 2007.
[0038] Prstic, S., Iyengar, M., and Bar-Cohen, A., 2000, Bypass effect in high performance heat sinks, Proceedings of the International Thermal Science Seminar Bled, Slovenia, June 11-14.
[0039] Mills, A. F., 1999, Heat transfer, Second edition, Prentice Hall.
[0040] Potter, C. M. and Wiggert, D. C., 2002, Mechanics of fluid, Third Edition, Brooks/Cole.
[0041] White, F. M., 1999, Fluid mechanics, Fourth edition, McGraw-Hill International.
[0042] Azar, A, et al., 2009, “Heat sink testing methods and common oversights”, Qpedia Thermal E-Magazine, January 2009 Issue.
[0000] www.qats.com/cpanel/UploadedPdf/January20092.pdf
[0043] Several structurally complex heatsink designs are discussed in Hernon, US App. 2009/0321045, incorporated herein by reference.
[0044] Heatsinks operate by removing heat from an object to be cooled into the surrounding air, gas or liquid through convection and radiation. Convection occurs when heat is either carried passively from one point to another by fluid motion (forced convection) or when heat itself causes fluid motion (free convection). When forced convection and free convection occur together, the process is termed mixed convection. Radiation occurs when energy, for example in the form of heat, travels through a medium or through space and is ultimately absorbed by another body. Thermal radiation is the process by which the surface of an object radiates its thermal energy in the form of electromagnetic waves. Infrared radiation from a common household radiator or electric heater is an example of thermal radiation, as is the heat and light (IR and visible EM waves) emitted by a glowing incandescent light bulb. Thermal radiation is generated when heat from the movement of charged particles within atoms is converted to electromagnetic radiation.
[0045] A heatsink tends to decrease the maximum temperature of the exposed surface, because the power is transferred to a larger volume. This leads to a possibility of diminishing return on larger heatsinks, since the radiative and convective dissipation tends to be related to the temperature differential between the heatsink surface and the external medium. Therefore, if the heatsink is oversized, the efficiency of heat shedding is poor. If the heatsink is undersized, the object may be insufficiently cooled, the surface of the heatsink dangerously hot, and the heat shedding not much greater than the object itself absent the heatsink.
[0046] The relationship between friction and convention in heatsinks is discussed by Frigus Primore in “A Method for Comparing Heat Sinks Based on Reynolds Analogy,” available at www.frigprim.com/downloads/Reynolds_analogy_heatsinks.PDF, last accessed Apr. 28, 2010. This article notes that for, plates, parallel plates, and cylinders to be cooled, it is necessary for the velocity of the surrounding fluid to be low in order to minimize mechanical power losses. However, larger surface flow velocities will increase the heat transfer efficiency, especially where the flow near the surface is turbulent, and substantially disrupts a stagnant surface boundary layer. Primore also discusses heatsink fin shapes and notes that no fin shape offers any heat dissipation or weight advantage compared with planar fins, and that straight fins minimize pressure losses while maximizing heat flow. Therefore, the art generally teaches that generally flat and planar surfaces are appropriate for most heatsinks.
[0047] Frigus Primore, “Natural Convection and Inclined Parallel Plates,” www.frigprim.com/articels2/parallel_pI_Inc.html, last accessed Apr. 29, 2010, discusses the use of natural convection (i.e., convection due to the thermal expansion of a gas surrounding a solid heatsink in normal operating conditions) to cool electronics. One of the design goals of various heatsinks is to increase the rate of natural convection. Primore suggests using parallel plates to attain this result. Once again, Primore notes that parallel plate heat sinks are the most efficient and attempts to define the optimal spacing and angle (relative to the direction of the fluid flow) of the heat sinks according to the equations in FIG. 1 .
[0048] In another article titled “Natural Convection and Chimneys,” available at www.frigprim.com/articels2/parallel_plchim.html, last accessed Apr. 29, 2010, Frigus Primore discusses the use of parallel plates in chimney heat sinks. One purpose of this type of design is to combine more efficient natural convection with a chimney. Primore notes that the design suffers if there is laminar flow (which creates a re-circulation region in the fluid outlet, thereby completely eliminating the benefit of the chimney) but benefits if there is turbulent flow which allows heat to travel from the parallel plates into the chimney and surrounding fluid.
[0049] In “Sub-Grid Turbulence Modeling for Unsteady Flow with Acoustic Resonance,” available at www.metacomptech.com/cfd++/00-0473.pdf, last accessed Apr. 29, 2010, incorporated herein by reference, Paul Batten et al discuss that when a fluid is flowing around an obstacle, localized geometric features, such as concave regions or cavities, create pockets of separated flow which can generate self-sustaining oscillations and acoustic resonance. The concave regions or cavities serve to substantially reduce narrow band acoustic resonance as compared to flat surfaces. This is beneficial to a heat sink in a turbulent flow environment because it allows for the reduction of oscillations and acoustic resonance, and therefore for an increase in the energy available for heat transfer.
[0050] In S. Liu, “Heat Transfer and Pressure Drop in Fractal Microchannel Heat Sink for Cooling of Electronic Chips,” 44 Heat Mass Transfer 221 (2007), Liu et al discuss a heatsink with a “fractal-like branching flow network.” Liu's heatsink includes channels through which fluids would flow in order to exchange heat with the heatsink.
[0051] Y. J. Lee, “Enhanced Microchannel Heat Sinks Using Oblique Fins,” IPACK 2009-89059, similarly discusses a heat sink comprising a “fractal-shaped microchannel based on the fractal pattern of mammalian circulatory and respiratory system.” Lee's idea, similar to that of Liu, is that there would be channels inside the heatsink through which a fluid could flow to exchange heat with the heatsink. The stated improvement in Lee's heatsink is (1) the disruption of the thermal boundary layer development; and (2) the generation of secondary flows.
[0052] Pence, D. V., 2002, “Reduced Pumping Power and Wall Temperature in Microchannel Heat Sinks with Fractal-like Branching Channel Networks”, Microscale Thermophys. Eng. 5, pp. 293-311, similarly, mentions heatsinks that have fractal-like channels allowing fluid to enter into the heat sink. The described advantage of Pence's structure is increased exposure of the heat sink to the fluid and lower pressure drops of the fluid while in the heatsink.
[0053] In general, a properly designed heatsink system will take advantage of thermally induced convection or forced air (e.g., a fan). In general, a turbulent flow near the surface of the heatsink disturbs a stagnant surface layer, and improves performance. In many cases, the heatsink operates in a non-ideal environment subject to dust or oil; therefore, the heatsink design must accommodate the typical operating conditions, in addition to the as-manufactured state.
[0054] Prior art heatsink designs have traditionally concentrated on geometry that is Euclidian, involving structures such as the pin fins, straight fins, and flares discussed above.
[0055] N J Ryan, D A Stone, “Application of the FD-TD method to modelling the electromagnetic radiation from heatsinks”, IEEE International Conference on Electromagnetic Compatibility, 1997. 10th (1-3 Sep. 1997), pp: 119-124, discloses a fractal antenna which also serves as a heatsink in a radio frequency transmitter.
[0056] Lance Covert, Jenshan Lin, Dan Janning, Thomas Dalrymple, “5.8 GHz orientation-specific extruded-fin heatsink antennas for 3D RF system integration”, 23 Apr. 2008 DOI: 10.1002/mop.23478, Microwave and Optical Technology Letters Volume 50, Issue 7, pages 1826-1831, July 2008 also provide a heatsink which can be used as an antenna.
SUMMARY OF THE INVENTION
[0057] Most heatsinks are designed using a linear or exponential relationship of the heat transfer and dissipating elements. A known geometry which has not generally been employed is fractal geometry. Some fractals are random fractals, which are also termed chaotic or Brownian fractals and include random noise components. In deterministic fractal geometry, a self-similar structure results from the repetition of a design or motif (or “generator”) using a recursive algorithm, on a series of different size scales. As a result, certain types of fractal images or structures appear to have self-similarity over a broad range of scales. On the other hand, no two ranges within the design are identical.
[0058] A fractal is defined as “a rough or fragmented geometric shape that can be split into parts, each of which is (at least approximately) a reduced-size copy of the whole.” Mandelbrot, B. B. (1982). That is, there is a recursive algorithm which describes the structure. The Fractal Geometry of Nature. W. H. Freeman and Company. ISBN 0-7167-1186-9. This property is termed “self-similarity.” For a more detailed discussion of fractals, see the Wikipedia article thereon at en.wikipedia.org/wiki/Fractal (last accessed Apr. 14, 2010) incorporated herein by reference. Exemplary images of well-known fractal designs can also be viewed on the Wikipedia page. Due to the fact that fractals involve largely self-repeating patterns, each of which serves to increase the surface area in three-dimensional fractals (perimeter in two-dimensional fractals), three dimensional fractals in theory are characterized by infinite surface area (and two-dimensional fractals are characterized by infinite perimeter). In practical implementations, the scale of the smallest features which remain true to the generating algorithm may be 3-25 iterations of the algorithm. Less than three recursions, and the fractal nature is not apparent, while present manufacturing technologies limit the manufacture of objects with a large range of feature scales.
[0059] This fractal nature is useful in a heatsink because the rate at which heat is transferred from a surface, either through convection or through radiation, is typically related to, and increasing with, the surface area. Of course, due to limitations in the technology used to build these heatsinks, engineering compromise is expected. However a feature of an embodiment of the designs proposed herein is that vortices induced by fluid flow over a heat transfer surface will be chaotically distributed over various elements of the surface, thus disrupting the stagnant surface boundary layer and increasing the effective surface area available for heat transfer, while avoiding acoustic resonance which may be apparent from a regular array of structures which produce vortices and turbulence.
[0060] Further, a large physical surface area to volume ratio, which is generally useful in heatsink design, can still be obtained using the fractal model. In addition, fractal structures provide a plurality of concave regions or cavities, providing pockets of separated flow which can generate self-sustaining oscillations and acoustic resonance. These pockets serve to reduce the acoustic resonance in turbulent flowing fluid (as compared to flat or Euclidian surfaces), thus allowing for more effective heat transfer between the fractal structure and the surrounding fluid, thereby making the fractal structure ideal for a heatsink.
[0061] U.S. Pat. No. 7,256,751, issued to Cohen, incorporated herein by reference, discusses fractal antennas. In the background of this patent, Cohen discusses Kraus' research, noting that Euclidian antennas with low area (and therefore low perimeter) exhibit very low radiation resistance and are thus inefficient. Cohen notes that the advantages of fractal antennas, over traditional antennas with Euclidian geometries, is that they can maintain the small area, while having a larger perimeter, allowing for a higher radiation resistance. Also, Cohen's fractal antenna features non-harmonic resonance frequencies, good bandwidth, high efficiency, and an acceptable standing wave ratio.
[0062] In the instant invention, this same wave theory may be applied to fractal heatsinks, especially with respect to the interaction of the heat transfer fluid with the heatsink. Thus, while the heat conduction within a solid heatsink is typically not modeled as a wave (though modern thought applies phonon phenomena to graphene heat transport), the fluid surrounding the heating certainly is subject to wave phenomena, complex impedances, and indeed the chaotic nature of fluid eddies may interact with the chaotic surface configuration of the heatsink.
[0063] The efficiency of capturing electric waves in a fractal antenna, achieved by Cohen, in some cases can be translated into an efficiency transferring heat out of an object to be cooled in a fractal heatsink as described herein. See, Boris Yakobson, “Acoustic waves may cool microelectronics”, Nano Letters, ACS (2010). Some physics scholars have suggested that heat can be modeled as a set of phonons. Convection and thermal radiation can therefore be modeled as the movement of phonons. A phonon is a quasiparticle characterized by the quantization of the modes of lattice vibration of solid crystal structures. Any vibration by a single phonon is in the normal mode of classical mechanics, meaning that the lattice oscillates in the same frequency. Any other arbitrary lattice vibration can be considered a superposition of these elementary vibrations. Under the phonon model, heat travels in waves, with a wavelength on the order of 1 μm. In most materials, the phonons are incoherent, and therefore a macroscopic scales, the wave nature of heat transport is not apparent or exploitable.
[0064] The thermodynamic properties of a solid are directly related to its phonon structure. The entire set of all possible phonons combine in what is known as the phonon density of states which determines the heat capacity of a crystal. At absolute zero temperature (0 Kelvin or −273 Celsius), a crystal lattice lies in its ground state, and contains no phonons. A lattice at a non-zero temperature has an energy that is not constant, but fluctuates randomly about some mean value. These energy fluctuations are caused by random lattice vibrations, which can be viewed as a gas-like structure of phonons or thermal phonons. However, unlike the atoms which make up an ordinary gas, thermal phonons can be created and destroyed by random energy fluctuations. In the language of statistical mechanics this means that the chemical potential for adding a phonon is zero. For a more detailed description of phonon theory, see the Wikipedia article thereon available at en.wikipedia.org/wiki/Phonon (last accessed Apr. 16, 2010) incorporated herein by reference.
[0065] In certain materials, such as graphene, phonon transport phenomena are apparent at macroscopic levels, which make phonon impedance measurable and useful. Thus, if a graphene sheet were formed to resonate at a particular phonon wavelength, the resonant energy would not be emitted. On the other hand, if the graphene sheet were configured using a fractal geometry, the phonon impedance would be well controlled over a broad range of wavelengths, with sharp resonances at none, leading to an efficient energy dissipation device.
[0066] Many fractal designs are characterized by concave regions or cavities. See, for example, FIGS. 2 and 3 . While sets of concavities may be useful in improving aerodynamics and fluid dynamics to increase turbulence, if they are disposed in a regular array, they will likely produce an acoustic resonance, and may have peaks in a fluid impedance function. On the other hand, the multiscale nature of a fractal geometric design will allow the system to benefit from the concavities, while avoiding a narrowly tuned system.
[0067] The present system proposes a fractal-shaped heatsink for the purpose of dissipating heat. The benefits of a fractal heatsink, over a traditional heatsink having a Euclidian geometry may include: (1) the fractal heatsink has a greater surface area, allowing for more exposure of the hot device to the surrounding air or liquid and faster dissipation of heat; and (2) due to the plethora of concave structures or cavities in fractal structures, the fractal heatsink is better able to take advantage of flow mechanics than a traditional heatsink, resulting in heat entering and exiting the heatsink more quickly (3) acoustic properties, especially in forced convection systems.
[0068] The invention provides a heatsink to cool an object through convection or radiation. For the smallest heatsink elements, on the order of 10-100 nm, the focus of the heat transfer will be on radiation rather than convection. Electron emission and ionization may also be relevant. Larger heatsink elements, approximately >1 mm in size, will generally rely on convection as the primary form of heat transfer.
[0069] In one embodiment, the heatsink comprises a heat exchange device with a plurality of heat exchange elements having a fractal variation therebetween. A heat transfer fluid, such as air, water, or another gas or liquid, is induced to flow through the heat exchange device. The heat transfer fluid has turbulent portions. The fractal variation in the plurality of heat exchange elements substantially reduces the narrow band acoustic resonance as compared to a heatsink having a linear or Euclidian geometric variation between the plurality heat exchange elements. The turbulent flow also disturbs the stagnant surface boundary layer, leading to more efficient heat transfer.
[0070] When a heat transfer fluid (air, gas or liquid) is induced to flow over a surface, there may be turbulence in the fluid. The fractal shape of the heatsink serves to reduce the energy lost due to the turbulence, while increasing the surface area of the heatsink subject to turbulence, due to the plethora of concave regions, cavities, and pockets. Therefore, the efficiency of heat transfer may be increased as compared to a heat exchange device having a linear or Euclidian geometric variation between several heat exchange elements.
[0071] Preferably, the heat exchange device will include a highly conductive substance whose heat conductivity exceeds 850 W/(m*K). Examples of such superconductors include graphene, diamond, and diamond-like coatings. Alternatively, the heat exchange device may include carbon nanotubes.
[0072] Various variations on this heatsink will be apparent to skilled persons in the art. For example, the heatsink could include a heat transfer surface that is connected to the heat exchange device and is designed to accept a solid to be cooled. Alternatively, there could be a connector that is designed to connect with a solid to be cooled in at least one point. In another embodiment, there are at least three connectors serving to keep the solid and the heatsink in a fixed position relative to one another. Various connectors will be apparent to persons skilled in the art. For example, the connector could be a point connector, a bus, a wire, a planar connector or a three-dimensional connector. In another embodiment, the heatsink has an aperture or void in the center thereof designed to accept a solid to be cooled.
[0073] This heatsink is intended to be used to cool objects, and may be part of a passive or active system. Modern three-dimensional laser and liquid printers can create objects such as the heatsinks described herein with a resolution of features on the order of about 16 μm, making it feasible for those of skilled in the art to use such fabrication technologies to produce objects with a size below 10 cm. Alternatively, larger heatsinks, such as car radiators, can be manufactured in a traditional manner, designed with an architecture of elements having a fractal configuration. For example, a liquid-to-gas heat exchanger (radiator) may be provided in which segments of fluid flow conduit have a fractal relationship over three levels of recursion, i.e., paths with an average of at least two branches. Other fractal design concepts may be applied concurrently, as may be appropriate.
[0074] Yet another embodiment of the invention involves a method of cooling a solid by connecting the solid with a heatsink. The heatsink comprises a heat exchange device having a plurality of heat exchange elements having a fractal variation therebetween. A heat transfer fluid having turbulent portions is induced to flow with respect to the plurality of heat exchange elements. The fractal variation in the plurality of heat exchange elements serves to substantially reduce narrow band resonance as compared to a corresponding heat exchange device having a linear or Euclidean geometric variation between a plurality of heat exchange elements.
[0075] A preferred embodiment provides a surface of a solid heatsink, e.g., an internal or external surface, having fluid thermodynamical properties adapted to generate an asymmetric pattern of vortices over the surface over a range of fluid flow rates. For example, the range may comprise a range of natural convective fluid flow rates arising from use of the heatsink to cool a heat-emissive object. The range may also comprise a range of flow rates arising from a forced convective flow (e.g., a fan) over the heatsink.
[0076] The heatsink may cool an unconstrained or uncontained fluid, generally over an external surface of a heatsink, or a constrained or contained fluid, generally within an internal surface of a heatsink.
BRIEF DESCRIPTION OF THE DRAWINGS
[0077] FIG. 1 shows a set of governing equations for a parallel plate heatsink.
[0078] FIG. 2 illustrates a fractal heatsink that is an exemplary embodiment of the invention. In this embodiment, the heatsink is placed adjacent to the object to be cooled.
[0079] FIG. 3 illustrates a fractal heatsink that is an exemplary embodiment of the invention. In this embodiment, the heatsink is placed either adjacent to or surrounding the object to be cooled.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0080] FIG. 2 illustrates a heatsink implementing an exemplary embodiment of this invention. Note that the illustration is in two dimensions, but a three dimensional embodiment is both possible and preferred. There is a heat transfer surface 100 that allows the heatsink to rest comfortably on a surface, such as the solid to be cooled 190 . In the illustrated embodiment, the heat transfer surface 100 is roughly planar, having a closed Euclidian cross-section on the bottom. However, it might also have another shape, for example if the solid to be cooled does not have a planar face. A fractal-shaped heat exchange device begins at point 110 . While only one fractal heatsink is illustrated here, skilled persons in the art will recognize other similar fractal heatsinks that are also intended to be covered by the invention. Note that the heatsink has three branches leaving from point 110 —branch 120 , branch 140 , and branch 160 . Also note that the branch structure initiating from point 110 is nearly identical to that at point 122 and 142 , even though only point 110 is a true starting point. Thus, the fractal property of self-similarity is preserved. We call the structure that begins at point 110 the “first motif,” the structure from point 122 the “second motif,” and the structure that begins from point 142 the “third motif.” Note that, in the embodiment illustrated in FIG. 2 , the replication from first to second motif and from second to third motif involves a linear displacement (upward) and a change of scale. In branches not going in the same direction as the prior branch, there is also a rotation. Under the limitations for ideal fractals, the second motif and third motif must be a smaller, exact copy of the first motif. However, due to the limitations imposed by human-made structures and machines, the fractals designed here are generally finite and the second motif will thus be an inexact copy of the first motif, i.e. if there are N levels starting from the first motif, the second motif level will have N-1 levels, if N is very large, the difference is insignificant. In other words, the self-similarity element required in fractals is not preserved perfectly in the preferred designs due to the limitations of available machinery. In addition, the benefits are achieved without requiring fractal relationships over more than a few “orders” of magnitude (iterations of the fractal recursive algorithm). For example, in the embodiment illustrated in FIG. 2 , there are no continuing branch divisions and iterations at point 162 , even though an ideal fractal would have them. In an ideal fractal, there would be an infinite number of sub-branches from 110 , 122 , and 142 . However, an imperfect fractal shape, as illustrated in FIG. 2 , will serve the purposes of this invention.
[0081] Persons of ordinary skill in the art will appreciate the advantages offered by the structure 110 in FIG. 2 . The fractal heatsink has a much larger surface area than the heat transfer surface alone because all of the “branches” and “leaves” of the fern-like fractal shape serve to increase the surface area. In addition, if a heat transfer fluid is induced to flow above the heat transfer surface 100 , the turbulent portions of the heat transfer fluid near the surface will be increased by the textures inherent in the fractal variation in the heat exchange element 110 . Because the fractal patterns is itself non-identically repeating within the fractal design, this will serve to substantially reduce narrow band acoustic resonance as compared to a corresponding heat exchange device having a repeating design, e.g., a linear or geometric variation between several heat exchange elements, thereby further aiding in the heat transfer process.
[0082] In a preferred embodiment, the heat transfer surface 100 and the roughly fractal-shaped heat exchange element 110 are all made out of an efficient heat conductor, such as copper or aluminum, or more preferably, having a portion whose heat conductivity exceeds 850 W/(m*K), such as graphene with a heat conductivity of between 4840 and 5300 W/(m*K) or diamond with a heat conductivity between 900 and 2320 W/(m*K). This would allow heat to quickly enter the heatsink from the solid and for heat to quickly exit the heatsink through the branches and leaves of the fern-like fractal 110 . In another embodiment, the heatsink is formed, at least in part, of carbon nanotubes, which display anisotropic heat conduction, with an efficient heat transfer along the long axis of the tube. Carbon nanotubes are submicroscopic hollow tubes made of a chicken-wire-like or lattice of carbon atoms. These tubes have a diameter of just a few nanometers and are highly heat conductive, transferring heat much faster than diamond, and in some cases comparable to graphene. See web.mit.edu/press/2010/thermopower-waves.html (last accessed Apr. 15, 2010) incorporated herein by reference.
[0083] Also note that this exemplary embodiment provides a plethora of openings, e.g. 124 and 126 , between the branches or fractal subelements to ensure that all of the branches are exposed to the surrounding air, gas or liquid and to allow the heat to escape from the heatsink into the surroundings. In one embodiment of the invention, at least two of these openings are congruent, as are openings 124 and 126 illustrated here. An embodiment of the invention allows the openings to be filled with the air or liquid from the surrounding medium. Due to the limitation imposed by the solid's flat shape, it is not possible to increase the exposure of the fern-like fractal to the solid. However, the air or liquid outside of the solid are perfect for the fractal's exposure.
[0084] Under the phonon model of heat exchange, applicable to carbon nanotubes, graphene materials, and perhaps others, the fractal shape is advantageous to ensure the escape of the phonons into the surrounding fluid medium because the fractal guarantees close to maximal surface exposure to the medium and does not have many parts that are not exposed, as is a problem with many prior art heatsinks. Skilled persons in the art will realize that this could be achieved through many known structures. For example, graphene, which is one-atom-thick carbon and highly heat conductive, would be an advantageous material to use to build the fractal heatsink herein described.
[0085] When a turbulently flowing fluid passes around an obstacle, concave regions or cavities in the obstacle create pockets of separated flow which generates self-sustaining oscillations and acoustic resonance. The concave regions or cavities have substantially reduced narrow band acoustic resonance as compared to flat regions on the obstacle. This allows for more energy to be available for heat transfer. Skilled persons in the art will note that fractal structure 110 , as many other fractal structures, has a plurality of concave regions to allow for an implementation of this effect.
[0086] FIG. 3 illustrates another embodiment of the invention. A solid to be cooled that has an arbitrary shape 290 is located inside (illustrated) or outside (not illustrated) a two-dimensional or three-dimensional roughly fractal shaped 210 heatsink. In one embodiment, the heatsink 210 has an aperture 270 designed to hold the solid. Alternatively, the solid to be cooled might be located outside of the heatsink (not illustrated). Note that, as in FIG. 2 , the fractal heat exchange element has multiple motifs, starting with the large triangle at 210 , to progressively smaller triangles at 220 and 230 . However, note that the fractal does not keep extending infinitely and there are no triangles smaller than the one at 230 . In other words, the fractal heatsink 210 has multiple recursive fractal iterations 220 and 230 , but the fractal iterations stop at level 230 for simplicity of design and manufacturability. Also note that the fractal submotifs 220 and 230 are of different dimensional sizes from the original fractal motif 210 and protrude from the original fractal shape 210 . Here, the first motif is a large triangle, and the latter motifs are smaller triangles, which involve a rotation, linear displacement, and change of scale of the prior motif. In one embodiment, the fractal shape has some apertures in it (not illustrated) to allow the solid to be cooled to connect with other elements. Also, the solid to be cooled is connected to the fractal shape at point connector 240 and through bus wires at 250 and 260 . The solid should be connected to the fractal heatsink in at least one point, either through a point connection, a bus wire connection, or some other connection. If it is desired that the solid be fixed inside the heatsink, there may be at least three connection points, as illustrated. However, only one connection point is necessary for heat convection and radiation from the solid to the heatsink. Preferably, the point or bus wire connection is built using a strong heat conductor, such as carbon nanotubes or a diamond-like coating.
[0087] Note that, as in FIG. 1 , the fractal structure 210 in FIG. 2 has multiple concave regions or cavities. When a turbulently flowing fluid passes around this fractal heatsink, the concave regions or cavities substantially reduce the narrow band acoustic resonance as compared to a flat or Euclidian structure. This allows for more energy to be available to for heat transfer.
[0088] In yet another embodiment of the invention, the heatsink 210 in FIG. 3 could be constructed without the connections at points 240 , 250 , and 260 . In one embodiment, a liquid or gas would fill the aperture 270 with the intent that the liquid or gas surround the solid to be cooled, hold it in place, or suspend it. Preferably, the liquid or gas surrounding the solid would conduct heat from the solid to the heatsink, which would then cause the heat to exit.
[0089] Those skilled in the art will recognize many ways to fabricate the heatsinks described herein. For example, modern three-dimensional laser and liquid printers can create objects such as the heatsinks described herein with a resolution of features on the order of 16 μm. Also, it is possible to grow a crystal structure using a recursive growth algorithm or through crystal growth techniques. For example, US Patent Application No. 2006/0037177 by Blum, incorporated herein by reference, describes a method of controlling crystal growth to produce fractals or other structures through the use of spectral energy patterns by adjusting the temperature, pressure, and electromagnetic energy to which the crystal is exposed. This method might be used to fabricate the heatsinks described herein. For larger heatsinks, such as those intended to be used in car radiators, traditional manufacturing methods for large equipment can be adapted to create the fractal structures described herein.
[0090] In this disclosure, we have described several embodiments of this broad invention. Persons skilled in the art will definitely have other ideas as to how the teachings of this specification can be used. It is not our intent to limit this broad invention to the embodiments described in the specification. Rather, the invention is limited by the following claims.
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A heatsink comprising a heat exchange device having a plurality of heat exchange elements each having a surface boundary with respect to a heat transfer fluid, having a fractal variation therebetween, wherein the heat transfer fluid is induced to flow with respect to the plurality of fractally varying heat exchange elements such that flow-induced vortices are generated at non-corresponding locations of the plurality of fractally varying heat exchange elements, resulting in a reduced resonance as compared to a corresponding heat exchange device having a plurality of heat exchange elements that produce flow-induced vortices at corresponding locations on the plurality of heat exchange elements.
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BACKGROUND OF THE INVENTION
The present invention relates to new rubber compositions intended for the manufacture of tire casings based on precipitated silicas containing a reinforcing additive based on a functionalized polyorganosiloxane and an organosilane compound.
Since the economies of fuel and the need to protect the environment have become a priority, it is desirable to produce polymers which have good mechanical properties and a hysteresis which is as low as possible in order to enable them to be used in the form of rubbery compositions which can be employed for the manufacture of various semifinished products forming part of the constitution of tire casings, such as, for example, underlinings, calendering or sidewall rubbers or treads and to obtain tires with improved properties, which have in particular a reduced rolling resistance.
Many solutions have been proposed to meet such an objective, consisting especially in modifying, among others, the nature of the diene polymers and copolymers at the end of polymerization by means of coupling or starring or functionalizing agents. All these solutions have concentrated essentially on the use of the modified polymers with carbon black as reinforcing filler with the aim of obtaining a good interaction between the modified polymer and the carbon black. It is known, in general, that in order to obtain optimum reinforcing properties which are imparted by a filler it is appropriate that the latter should be present in the elastomer matrix in a final form which is both as finely divided as possible and distributed as homogeneously as possible. However, such conditions can be achieved only insofar as, on the one hand, the filler has a very good capacity for being incorporated into the matrix during the mixing with the elastomer and for being deaggregated or deagglomerated and for being dispersed homogeneously in the elastomer. The use of white reinforcing fillers, and especially of silica, has been found inappropriate because of the low level of some properties of such compositions and consequently of some properties of the tires utilizing these compositions.
In addition, for reasons of mutual affinities, silica particles have an unfortunate tendency, in the elastomer matrix, to agglomerate together. These silica/silica interactions have the detrimental consequence of limiting the reinforcing properties to a level which is appreciably lower than that which it would be theoretically possible to attain if all the silica/elastomer interactions capable of being created during the mixing operation were actually obtained.
What is more, the use of silica gives rise to difficulties in processing which are due to the silica/silica interactions which tend, in the raw state (before curing), to increase the consistency of the rubbery compositions and, in any event, to make the processing more difficult than the processing of carbon black.
Finally, the interactions between the silica and the crosslinking system, when the latter is sulfur-based, and the accelerators usually employed in the case of sulfur reduce the rate and efficiency of crosslinking.
In the case of silica-reinforced compositions interest has been revived with the publication of European Patent Application EP-A-0 501 227, which discloses a sulfur-vulcanizable rubber composition obtained by thermomechanical working of a copolymer of conjugated diene and of an aromatic vinyl compound, prepared by polymerization in solution with 30 to 150 parts by weight, per 100 parts by weight of elastomer, of a particular precipitated silica. The use of such a silica has undoubtedly reduced the difficulties in processing the mixtures containing it, predominantly or otherwise, as reinforcing filler, but the processing of such rubbery compositions nevertheless remains more difficult than the processing of carbon black.
It is known to a person skilled in the art that a coupling or bonding agent which reacts with silica must be employed to create good interactions between the surface of the silica and the elastomer while promoting the dispersion of the silica, and the compositions described in European Patent Application EP-A-0 501 227 are also subject to this need.
One objective of a person skilled in the art consists in improving the processing of the diene rubber compositions including silica as reinforcing filler which are intended for the manufacture of tire casings and, on the other hand, to reduce the quantity of coupling and/or reinforcing agent needed, without degrading the properties of such compositions.
Thus, in U.S. Pat. No. 3,350,345 it has been proposed to employ, in rubber compositions including silica, a hydrolyzable silane and in particular a mercaptosilane as elastomer/silica coupling agent. In Patent Application FR-A-2,094,859 it was subsequently proposed to employ rubber compositions including silica and a mercaptosilane as coupling agent for the manufacture of tire treads, because of the improved properties exhibited by such compositions. It was rapidly demonstrated and known to a person skilled in the art that mercaptosilanes and in particular γ-mercaptopropyltrimethoxysilane and γ-mercaptopropyltriethoxysilane were capable of providing the best silica/elastomer coupling properties, but that the industrial use of these coupling agents was not possible because of the high reactivity of the SH functional groups resulting very rapidly, during the preparation of a composition in an internal mixer, in premature vulcanizations, also called "scorching", with very high Mooney plasticities and, all things considered, in compositions which were virtually impossible to work and to process on industrial scale.
To illustrate this impossibility of employing such coupling agents and the compositions containing them on industrial scale, Patent Application FR-A-2,206,330 and U.S. Pat. No. 4,002,594 may be mentioned.
To overcome this disadvantage, in Patent Application FR-A-2,206,330 it has been proposed to employ as coupling agent organosilane polysulfides, including bis-3-triethoxysilylpropyl tetrasulfide, which are found to give the best compromise, in the case of silica-filled vulcanizates, in terms of scorch safety, ease of processing and reinforcing power. However, this coupling agent is very costly and must be employed in a relatively large quantity, of the order of 2 to 3 times greater than the quantity of γ-mercaptopropyltrimethoxysilane needed to obtain equivalent coupling property levels.
Consequently, it therefore appears desirable from an economical viewpoint to have the ability to develop on industrial scale silica-reinforced rubber compositions including low contents of reinforcing additives which are as effective as mercaptosilanes, but while avoiding premature scorching and problems in processing which are related to an excessive viscosity of the compositions.
An attempt in this direction was described in U.S. Pat. No. 4,474,908 which discloses the use of the mixture of a mercaptosilane and an alkoxysilane as reinforcing additive for a rubber composition.
However, this route is not a satisfactory remedy to the problem of scorching and of processing and, in addition, it is costly.
Another attempt has been described in Japanese Patent Application JP-A-06,248,116, which discloses rubber compositions intended for the manufacture of tire casings including, as reinforcing filler, a blend of carbon black and of silica surface treated with unfunctionalized silicone oils (generally and usually called PDMS by a person skilled in the art), as well as a silane as coupling agent. This route does not enable the problem faced by a person skilled in the art to be solved, whether the filler consists of a black/silica dilution or silica alone. In fact, the solution described in this application requires the pretreatment of the silica with the silicone oil at a high temperature (approximately 250° C.) and for an extended period (approximately 1 hour) before it is incorporated into the elastomer and into the coupling agent.
The present invention remedies the problem presented by the use, in rubber compositions based on at least one elastomer and intended for the manufacture of a tire casing which has improved hysteretic properties and which includes silica as reinforcing filler, of a reinforcing additive consisting of the mixture and/or the product of in situ reaction of at least one functionalized polyorganosiloxane compound containing, per molecule, at least one functional siloxy unit capable of bonding chemically and/or physically with the surface hydroxyl sites of the silica particles and at least one functionalized organosilane compound containing, per molecule, at least one functional group capable of bonding chemically and/or physically with the polyorganosiloxane and/or the hydroxyl sites of the silica particles and at least one other functional group capable of bonding chemically and/or physically to the chains of elastomer(s).
Another object of the invention is the use, for the manufacture of tire casings, of a rubber composition based on at least one elastomer, including silica as reinforcing filler and a reinforcing additive consisting of the mixture and/or the product of in situ reaction of at least one functionalized polyorganosiloxane compound containing, per molecule, at least one functional siloxy unit capable of bonding chemically and/or physically with the surface hydroxyl sites of the silica particles and at least one functionalized organosilane compound containing, per molecule, at least one functional group capable of bonding chemically and/or physically with the polyorganosiloxane and/or the hydroxyl sites of the silica particles and at least one other functional group capable of bonding chemically and/or physically to the chains of elastomer(s).
Another subject-matter of the present invention is semifinished constituents which can be employed in the manufacture of tires, especially of treads, and tires which have an improved rolling resistance, obtained by the use of a rubber composition according to the invention embodying silica as reinforcing filler.
Another subject-matter of the present invention is a process for improving the hysteretic properties of silica-reinforced rubber compositions intended for the manufacture of tire casings, and of semifinished products for tire casings.
Another subject-matter of the present invention is a tire casing including a rubber composition comprising at least one elastomer, silica as a reinforcing filler and a covering additive, wherein the covering additive consists of at least one functionalized polyorganosiloxane compound containing, per molecule, at least one functional siloxy unit capable of bonding chemically and/or physically with the surface hydroxyl sites present on the silica particles.
Finally, another subject-matter of the present invention is a process making it possible to delay substantially the scorching of diene rubber compositions intended for the manufacture of tire casings and of semifinished products for tire casings during the stages of preparation and processing of said compositions.
The reinforcing additive employed in the rubber compositions in accordance with the invention includes, on the one hand, one or a number of functionalized polyorganosiloxane compound(s) containing, per molecule, one or a number of functional siloxy unit(s) capable of bonding chemically and/or physically with the surface hydroxyl sites of the silica particles and, on the other hand, one or a number of functionalized organosilane compound(s). Particularly suitable among the functionalized polyorganosiloxanes are those in which the siloxy units contain a hydrolyzable functional substituent or one or a number of H or OH residue(s) whose reactivity towards silica differs from the other recurring functional substituent(s) of the polyorganosiloxane.
Any compound corresponding to any one of the following compounds may be chosen as suitable functionalized polyorganosiloxane compounds for the present invention:
(A)--the compounds containing, per molecule,
--α-- on the one hand, at least one functional siloxy unit of formula:
(R).sub.a YSi(O).sub.(3-a)/2 (I)
in which:
a=0, 1 or 2,
R is a monovalent hydrocarbon radical chosen from linear or branched alkyls containing from 1 to 6 carbon atoms, in particular methyl, ethyl, propyl and butyl and/or from aryls and in particular phenyl, methyl being more particularly preferred, the radicals R being identical or different when a=2,
Y is a linear or branched alkoxy radical chosen, preferably, from C 1 -C 15 and in particular C 1 -C 6 , alkoxys, methoxy, ethoxy and (iso)propoxy being more particularly adopted,
--β-- and optionally, on the other hand, at least one functional siloxy unit of formula:
(R).sub.b WSi(O).sub.(3-b)/2 (II)
in which:
b=0, 1 or 2,
R corresponds to the same definition as that given above for the substituent R of unit (I) and may be identical with or different from the latter,
W is a monovalent hydrocarbon radical containing from 2 to 30 carbon atoms and optionally S and/or O atoms and constituting a functional residue bonded to silicon by an Si-C bond, this residue being chosen from the following groups:
(i) a linear or branched alkyl group containing at least 7 carbon atoms,
(ii) a linear or branched C 2 -C 20 alkenyl group containing one or more double bond(s) in and/or at the end(s) of the chain(s) said double bonds being preferably conjugated and/or associated with at least one activating group in the α position,
(iii) a saturated or unsaturated aliphatic mono- or polycyclic group containing 5 to 20 carbon atoms and one or more ethylenic double bond(s) in the ring(s), optionally bonded to silicon through the intermediacy of a C 2 -C 10 linear or branched alkylene radical,
--γ-- and optionally, on the other hand, at least one siloxy unit of the following formula:
(R).sub.c (H).sub.d Si(O).sub.(4-(c+d)/2 (III)
in which:
c=0, 1, 2 or 3, d=1 and c+d≦3
the substituents R being as defined above in units (I) and (II).
According to a terminology which is conventional in silicones, the units (I) and (II) may be M, D and T units; in the latter case the polyorganosiloxanes are in the form of linear chains which are mutually crosslinked.
(B)--The compounds of formula (IV): ##STR1## in which: R is a hydrocarbon radical corresponding to the same definition as that of R given above as legend in formula (I), or a linear or branched C 2 -C 20 alkenyl group containing one or more double bonds. The various exemplars of R may be identical with or different from each other,
x=0 to 500, preferably x=0 to 50,
F and F' are monovalent radicals chosen from hydrogen, the halogens and preferably chlorine, those corresponding to the definition of R, and/or hydroxyl, alkoxy, enoxy, acyloxy, more particularly acetoxy, oxime and amine functional groups; the hydroxyl, methoxy and ethoxy functional groups being more particularly preferred. F and F' may be different or identical, but in the latter case it must not be a question of the radical R, and constitute the functional substituents of the functional siloxy units.
(C)--Polyorganosiloxane resins containing monovalent radicals and/or reactive functional groups F and F', these symbols having the same definition as that given above as legend in formula (IV).
The polyorganosiloxanes (A) are notable in that the functional substituent Y is hydrolyzable and allows grafting on silica, whereas the functional substituent W which is optionally present is hydrolyzable with greater difficulty than the functional substituent Y and is capable of expressing various properties as a function of its chemical nature.
The substituent W of the unit of formula (II) is preferably chosen from the following radicals:
a radical (i) containing from 10 to 30 carbon atoms and chosen preferably from the following alkyl radicals: dodecyl, undecyl, tridecyl;
a C 6 -C 10 radical (ii), containing a double bond and preferably another one, conjugated or unconjugated with the first one;
a saturated or unsaturated aliphatic monocyclic or polycyclic group (iii) containing 5 to 20 carbon atoms, more particularly cyclohexyl, cyclohexenyl or bicyclic rings originating from norbornene or from dicyclopentadiene, optionally linked to silicon through the intermediacy of a C 2 -C 6 linear or branched alkylene radical.
It is appropriate to emphasize that when more than one exemplar of a unit of a given type (I, II or III) is present in the polyorganosiloxane, the various exemplars may be identical with or different from each other. It is even possible advantageously to use this plurality to advantage. For example, functionalized polyorganosiloxanes simultaneously carrying ethoxy and methoxy functional groups as functional groups Y will enable a person skilled in the art to modulate the rate of reaction with the silica as a function of the respective percentages of the two functional groups.
Bearing in mind the values which can be taken by the indices a to d attributed to the substituents in the units (I), (II) and (III), it must be understood that the polyorganosiloxanes may exhibit a linear and/or branched and/or cyclic structure.
The preferred radicals R are: methyl, ethyl, n-propyl, isopropyl or n-butyl. Still more preferably, at least 80% of the number of the radicals R are methyls.
The preferred alkoxy radicals Y are ethoxys.
As preferred polyorganosiloxanes with which the invention is concerned there are mentioned first of all those formed by random, sequential or block linear copolymers of the following average formula (V): ##STR2## in which: the symbols Y, W and R are as defined above,
the symbol Z is a monovalent radical chosen from the radicals formed by hydrogen and from those corresponding to the definitions of R, Y and W,
the sum m+n+p+q≦3, preferably between 3 and 100; the illustrated case in which p=q=0, m≧1 and n≦50 being more particularly preferred,
0≦m≦100, preferably 1≦m≦50
0≦n≦100, preferably 1≦n≦50
0≦p≦20, preferably 0≦p≦10
0≦q≦40, preferably 0≦q≦10,
with the conditions according to which:
if m=0, at least one of the substituents Z corresponds to a radical corresponding to the definition characterizing Y
if m=n=0 and p+q≧1, then at least one of the substituents Z corresponds to a radical corresponding to the definition characterizing Y.
Among the polyorganosiloxanes of formula (V) which are more particularly preferred there may be mentioned those in the case of which p=q=1 and 0.5≦m/n≦5, preferably 1≦m/n≦3.
The compounds corresponding to the following formulae may be mentioned by way of examples of linear functionalized polyorganosiloxanes: ##STR3## with, on average, m: 35 and n: 15 ##STR4## with, on average, m: 29 and n: 15 and W corresponding to: --(CH 2 ) 7 --CH 3 ##STR5## with, on average, m: 23 and n: 8.5 and W corresponding to: --(CH 2 ) 4 --CH═CH 2 ##STR6## with, on average, m: 35 and n: 16 and W corresponding to: ##STR7##
An alternative to the linear structure of the polymers of formula (V) as defined above relates to polyorganosiloxanes consisting of cyclic copolymers of the following average formula: ##STR8## in which: Y, W and R are as defined above, and with r, s, t and u representing positive whole or decimal numbers,
the sum r+s+t+u≧3, preferably between 4 and 8, the case illustrated in which t=u=0 being more particularly preferred,
1≦r≦8, preferably 1≦r≦4
1≦s≦8, preferably 1≦s≦4
0≦t≦8, preferably 0≦t≦4
0≦u≦8, preferably 0≦u≦4.
The polyorganosiloxanes preferably consist of products corresponding to those in the case of which R=CH 3 and p=u=0 and q=t=0 in the formulae (V) and (VI) defined above.
It is obvious that, as already indicated above, in these formulae (V) and (VI) the radicals W may be of identical or different nature when n>1 and s>1.
A number of polyorganosiloxanes of the type defined above may, of course, be employed within the scope of the present invention.
These polyorganosiloxanes and especially the multifunctional polyorganosiloxanes are obtained according to a process consisting, on the one hand, in reacting a starting polyorganosiloxane containing units of formula (II) as defined above, in which W denotes hydrogen, with at least one alcohol from which the functionality Y of the unit (I) is derived, and used at the same time as a reactant and as reaction solvent, in the presence of a catalyst in which at least one of the active elements is chosen from the transition metals, according to a dehydrocondensation mechanism (1st stage), and, on the other hand, in using the addition of the polyorganosiloxane converted by dehydrocondensation to at least one olefinic compound from which the functionality W of the unit (II) is derived according to a hydrosilylation mechanism (2nd stage), in the presence of a catalyst and preferably at a temperature of between 5 and 100° C. and still more preferably between 5 and 70° C.
As a matter of priority, the alcohols used are monohydroxy linear or branched alkanols (primary, secondary or tertiary, preferably primary) which are preferably chosen from the following list: methanol, ethanol, (iso)propanol and (n) butanol, ethanol being preferred.
With regard to the catalyst, this is advantageously chosen from those containing at least one of the following elements: Pt, Rh, Ru, Pd and Ni and their combinations, this catalyst being optionally coupled to a support which is inert or otherwise.
According to a preferred arrangement of the invention, the catalyst is taken from the class of the platinum catalysts which are conventionally employed for carrying out hydrosilylation reactions. These platinum catalysts are extensively described in the literature. It is possible, in particular, to mention the complexes of platinum and of an organic product which are described in U.S. Pat. Nos. 3,159,601, 3,159,602, 3,220,972 and European Patents EP-A-57 459, EP-188 978, EP-A-190 530 and the complexes of platinum and of vinylorganopolysiloxane described in U.S. Pat. Nos. 3,419,593, 3,715,334, 3,377,432 and 3,814,730. The Karstedt catalyst is an example of platinum catalyst which is appropriate for the process according to the invention. (Karstedt U.S. Pat. No. 3,775,452).
Nickel-based catalysts like, for example, Raney nickel, constitute a possible alternative to the platinum catalysts.
Where the reaction conditions are concerned, the dehydrocondensation can be carried out over a wide range of temperature extending, for example, from 0 to 200° C., but it is clear that it is preferred that it should be performed at a temperature of between 10 and 50° C., preferably between 18 and 35° C.
The second stage of the process according to the invention consists of a reaction of addition of the hydrogenated intermediate polyorganosiloxane produced by dehydrocondensation to at least one olefinic compound carrying at least one π bond.
This involves a hydrosilylation mechanism, in the presence of a catalyst and, preferably, at a temperature between 5 and 100° C. and still more preferably between 5 and 70° C.
According to a preferred methodology the hydrosilylation is initiated by adding the olefinic compound from which the radical W as defined above is derived to the intermediate alkoxylated polyorganosiloxane, once the dehydrocondensation is finished. In practice this addition can take place when the release of hydrogen has ceased.
The reactive alkene may be formed by a mixture of products comprising a single or a number of precursor species of radicals W, which determine the multifunctionality of the final polyorganosiloxane. In the case where a number of species W are provided, the alkene corresponding to the second functionality is preferably allowed to react first of all and then, once the latter has reacted completely, the alkene corresponding to the third functionality is incorporated, and so on.
Instead of being incorporated into the reaction mixture after dehydrocondensation, the olefinic compound which is a precursor of W may be used before this first stage of the process begins, or else during it.
The olefinic compounds used can be easily deduced from the definition of W given above. The choice with regard to this radical is determined by the intended applications (one or a number of different functionalities).
The hydrosilylation stage may advantageously take place at ambient temperature and in bulk or in solution, for example in the alcohol which has been used as solvent for the dehydrocondensation reaction.
When the reactions are finished, the raw polyorganosiloxanes which are obtained may be purified particularly by being passed through a column filled with an ion exchange resin and/or by simple devolatilization of the excess reactants introduced and optionally of the solvent used, by heating which is performed between 100 and 180° C. at reduced pressure.
The starting polyorganosiloxane is advantageously selected from those corresponding to the following formula: ##STR9## in which: the symbols R are identical or different and are as defined above as legend to the formula of units (I) and (II),
the symbols Z' are identical or different and correspond to R or to hydrogen,
v is an integer or a decimal number ≧0 which can be defined as follows: v=n+m+p; n, m and p corresponding to the definitions given above as legend to the formula of unit (V), with the condition according to which if v=0 then w≧1 and both radicals Z' correspond to hydrogen,
w corresponds to the same definition as that of p given above as legend to the formula of unit (V).
The starting polyorganosiloxanes used, for example, for the preparation of the cyclic functionalized products are those selected from those corresponding to the following average formula: ##STR10## in which: the symbols R are identical or different and are as defined above, as legend to the formula of units (I) and (II),
o corresponds to the same definition as that of u given above, as legend to the formula of unit (VI),
y is an integer or a decimal number ≧0, which can be defined as follows: y=r+s+t and y+u≧3; r, s, t and u corresponding to the definitions given above as legend to the formula of unit (VI).
The following are preferably suitable as examples of compounds (B):
The silanol-ended polydimethylsiloxanes such as the following commercial products manufactured by Huls America Inc. which appear in the 1994 catalog of the company ABCR--Roth--Sochiel Sarl under the reference: ##STR11## with a denoting a positive integer, to give a weight-average mass between 400 and 700. ##STR12## with a denoting a positive integer, to give a weight-average mass of 4200.
The polydimethylsiloxanes ending in ethoxy groups, such as the products manufactured by Huls America Inc. and which appear in the 1994 catalog of the company ABCR--Roth--Sochiel Sarl under the reference: ##STR13## with a denoting a positive integer, to give a weight-average mass between 700 and 1200.
The compounds (C) are polyorganosiloxane resins consisting of small macromolecular networks of one or more ring(s) as a result of the presence of M, D, T or Q units in the molecule, according to a conventional silicone terminology, and containing monovalent radicals and/or reactive functional groups.
By way of example of such resins there may be mentioned the compounds corresponding to the formula: ##STR14## in which: n denotes the number of D units in each chain link of the ring: 0≧n1, n2, n3≦20
F and F' are monovalent radicals chosen from hydrogen, chlorine, those corresponding to the definition of R, and/or hydroxyl, alkoxy, enoxy, acyloxy, more particularly acetoxy, oxime and amine functional groups; the hydroxyl, methoxy and ethoxy functional groups being more particularly preferred; F and F' may be different or identical, but in the latter case it must not be the radical R.
It is obvious that the number of chain links of each ring may be greater than 3, just as the number of units F may be greater than 2, while being of the same kind or of different kinds.
By way of example of such resins there may be mentioned the MQ resins, the MDQ resins, the DT resins and the MDT resins, which have a hydroxyl or alkyl group weight content of between 1 and 6%.
More particularly, the resins which have a molecular mass lower than 25,000 may be employed.
By way or preferred example of compounds (C) there may be mentioned the polyorganosiloxane resin 4509 marketed by the company Rhone-Poulenc, in which the molar percentage of the various units M, D and T is: M=15%, D=25%, T=60%
and the percentage, by volume, of hydroxyl functional groups=0.5%.
Finally, it is possible within the scope of the invention to employ a mixture of at least two of the polyorganosiloxanes A, B and C.
One or more compounds corresponding to at least one of the following four general formulae (X) to (XIII) are suitable as organosilane compounds which can be employed within the scope of the invention: ##STR15## in which: R 1 denotes an alkyl group containing 1 to 10 carbon atoms, or else the phenyl radical,
X denotes a hydrolyzable group chosen from:
the halogens, preferably chlorine,
alkoxy or cycloalkoxy radicals,
acyloxy radicals,
after hydrolysis, X may optionally denote a hydroxyl group (OH).
0≦n≦2
(Alk) denotes a divalent hydrocarbon group chosen from linear or branched alkyls containing from 1 to 10 carbon atoms and advantageously from 1 to 6,
m denotes 0 or 1,
(Ar) denotes a hydrocarbon group chosen from aryls, containing from 6 to 12 carbon atoms and preferably 6 to 8,
p denotes 0 or 1, with the condition that p and m are not equal to 0 simultaneously,
q=1 or 2,
B denotes a group capable of forming a bond with at least one of the elastomers of the rubber composition. The preferred groups B are the mercapto (SH) groups in the case of q=1 and the polysulfide (Sx) and disulfide (S 2 ) groups in the case of q=2.
However, the group B may also include other groups capable of reaction with the rubbery polymer, for example:
B denotes:
if q=2: a polysulfured functional group chosen from the following groups:
--Sx-- with 1≦x≦8, x being a positive integer ##STR16## if q=1: a functional group chosen from the following groups: ##STR17## in which: R1 and X correspond to the same definition as that given above as legend to formula (X),
0≦n≦2,
(R2) denotes a divalent hydrocarbon group chosen from linear or branched alkyls and alkylenoxys, containing from 1 to 10 carbon atoms and advantageously from 1 to 6,
m denotes 0 or 1,
(Ar) denotes a hydrocarbon group chosen from aryls, containing from 6 to 12 carbon atoms,
(S) x is a divalent polysulfured radical, each free valency being bonded directly to a carbon atom of an aromatic ring, it being possible for a number of aromatic rings to be linked together by the radical (S) x
2≦x≦6,
a≧2 and b≧1 with 0.4≦a/b≦2 ##STR18## in which: R1 and X correspond to the same definition as that given above as legend to formula (X),
0≦n≦2,
Alkenyl denotes a linear or branched hydrocarbon group, cyclic or otherwise, containing one or more double bonds, containing from 2 to 20 carbon atoms and preferably from 2 to 6. The double bonds are preferably conjugated and/or associated at least with an activating group situated in the α position.
This class of bonding agent corresponding to the formula (XII) is preferably employed in rubber compositions with at least one radical initiator, preferably consisting of at least one peroxide. ##STR19## in which: the symbols R1, R3, X, X1, Alk, Alk1, n, n', m, m', Ar, Ar1, p and p' are identical or different and correspond to the same definition as that given above as legend to formula (X),
1≦x≦8, Sx therefore denotes a mono-, di- or polysulfide radical,
with the condition of not simultaneously having n=n', m=m', p=p', X=X1, R1=R3, Alk=Alk1 and Ar=Ar1.
Examples of commercial organosilane compounds are given in the table below. Of course, the invention is not limited to these compounds.
__________________________________________________________________________Chemical name Formula Trade name/supplier__________________________________________________________________________3-Mercaptopropyltrimethoxysilane HS(CH.sub.2).sub.3 Si(OCH.sub.3).sub.3 A-189/OSI 3-Mercaptopropyltriethoxysilane HS(CH.sub.2).sub.3 Si(OC.sub.2 H.sub.5). sub.3 Dynasylan 3201/Huls Vinyltriethoxysilane C.sub.2 H.sub.3 Si(OC.sub.2 H.sub.5).sub.3 Dynasylan VTEO/Huls 3-Aminopropyltriethoxysilane NH.sub.2 (CH.sub.2).sub.3 Si(OC.sub.2 H.sub.5).sub.3 A-1100/OSI 3-Methacryloxypropyltrimethoxysilane CH.sub.2 CCH.sub.3 COO(CH.sub.2).su b.3 Si(OCH.sub.3).sub.3 A-174/OSI Mercaptomethyldimethylethoxysilane HSCH.sub.2 Si(CH.sub.3).sub.2 (OC.sub.2 H.sub.5) M8200/ABCR Bis(triethoxysilylpropyl) tetrasulfide [(C.sub.2 H.sub.5 O).sub.3 Si(CH.sub.2).sub.3 S.sub.2 ].sub.2 Si 69/Degussa Bis(trimethoxysilylpropyl) tetrasulfide [(CH.sub.3 O).sub.3 Si(CH.sub.2) .sub.3 S.sub.2 ].sub.2 Si 167/Degussa 3-Chloropropyltrimethoxysilane (CH.sub.3 O).sub.3 Si(CH.sub.2).sub.3 Cl Si 130/Degussa 3-Thiocyanatopropyltriethoxysilane (C.sub.2 H.sub.5 O).sub.3 Si(CH.sub.2 ).sub.3 SCN Si 264/Degussa Bis(triethoxysilylethyltolyl) trisulfide [(C.sub.2 H.sub.5 O).sub.3 Si(CH.sub.2).sub.2 --C.sub.6 H.sub.5 (CH.sub.3).sub.2 [(S).sub.3 ] URC2/OSI__________________________________________________________________________
Any precipitated or pyrogenic silicas known to a person skilled in the art, which have a BET surface ≦450 m 2 /g and a CTAB specific surface ≦450 m 2 /g are suitable as silica capable of being used in the invention, even though the highly dispersible precipitated silicas are preferred.
A highly dispersible silica is intended to mean any silica which has a capacity for deagglomeration and for dispersion in a polymeric matrix which is very great and observable by electron or optical microscopy on thin sections. The dispersibility of the silica is also assessed by means of a test for capacity for being deagglomerated by ultrasonics, followed by a measurement, by scattering on a particle size analyzer, of the size of the silica particles, in order to determine the median diameter (D50) of the particles and the deagglomer-ation factor (Fd) after deagglomeration as described in Patent Application EP-A-0 520 860, the content of which is incorporated here, or in the article published in the journal Rubber World, June 1994, pages 20-24, entitled "Dispersibility Measurements of Prec. Silicas".
As nonlimiting examples of such preferred highly dispersible silicas there may be mentioned those which have a CTAB surface equal to or lower than 450 m 2 /g and particularly those described in European Patent Applications EP-A-0 157 703 and EP-A-0 520 862, the content of which is incorporated here, or the silica Perkasil KS 430 from the company Akzo, the silicas Zeosil 1165 MP and 85 MP from the company Rhone-Poulenc, the silica HI-Sil 2000 from the company PPG and the silicas Zeopol 8741 or 8745 from the company Huber.
However, by way of greater preference, the silicas which are suitable have:
a CTAB specific surface of between 120 and 200 m 2 /g, preferably between 145 and 180 m 2 /g,
a BET specific surface of between 120 and 200 m 2 /g, preferably between 150 and 190 m 2 /g,
a DOP oil uptake lower than 300 ml/100 g, preferably between 200 and 295 ml/100 g,
a median diameter (.o slashed.50), after ultrasonic deagglomeration, equal to or lower than 3 μm, preferably lower than 2.8 μm, for example lower than 2.5 μm,
an ultrasonic deagglomeration factor (FD) higher than 10 ml, preferably higher than 11 ml and more preferably ≧21 ml,
a BET specific/CTAB specific surface ratio ≧1.0 and ≧1.2.
The physical state in which the silica is present, that is to say whether it is present in the form of powder, of microbeads, of granules or of beads, is immaterial.
Silica is, of course, also intended to include blends of various silicas. The silica may be employed alone or in the presence of other white fillers. The CTAB specific surface is determined according to NFT method 45007 of November 1987. The BET specific surface is determined according to the Brunauer, Emmet and Teller method described in "The Journal of the American Chemical Society", vol. 80, page 309 (1938), corresponding to NFT standard 45007 of November 1987. The DOP oil uptake is determined according to NFT standard 30-022 (March 1953), using dioctyl phthalate.
Elastomers capable of being used in the compositions in accordance with the invention are intended to mean:
1) any homopolymer obtained by polymerization of a conjugated diene monomer containing from 4 to 12 carbon atoms,
2) any copolymer obtained by copolymerization of one or more conjugated dienes with each other or with one or a number of aromatic vinyl compounds containing from 8 to 20 carbon atoms,
3) the tertiary copolymers obtained by copolymerization of ethylene, of an α-olefin containing 3 to 6 carbon atoms with an unconjugated diene monomer containing from 6 to 12 carbon atoms, like, for example, the elastomers obtained from ethylene and propylene with an unconjugated diene monomer of the above-mentioned type such as especially 1,4-hexadiene, ethylidenenorbornene and dicyclopentadiene,
4) the copolymers obtained by copolymerization of isobutene and of isoprene (butyl rubber), as well as the halogenated, in particular chlorinated or brominated, versions of these copolymers.
Conjugated dienes which are particularly suitable are 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-di(C 1 -C 5 -alkyl)-1,3-butadienes such as, for example, 2,3-dimethyl-1,3-butadiene, 2,3-diethyl-1,3-butadiene, 2-methyl-3-ethyl-1,3-butadiene, 2-methyl-3-isopropyl-1,3-butadiene, phenyl-1,3-butadiene, 2-chloro-1,3-butadiene, 1,3-pentadiene, 2,4-hexadiene, and the like.
Aromatic vinyl compounds which are suitable are especially styrene, ortho-, meta- and para-methylstyrene, the commercial vinyltoluene mixture, para-tert-butylstyrene, methoxystyrenes, chlorostyrenes, vinylmesitylene, divinylbenzene, vinylnaphthalene, and the like.
The copolymers may contain between 99% and 20% by weight of diene units and from 1 to 80% by weight of vinylaromatic units. The elastomers may have any microstructure that is a function of the polymerization conditions employed, especially of the presence or absence of a modifying and/or randomizing agent and of the quantities of modifying and/or randomizing agent which are employed. The elastomers may be of block, random, sequential, microsequential or other structure and may be prepared in dispersion or in solution.
Those preferably suitable are the polybutadienes and in particular those which have a 1,2-unit content of between 4% and 80% and those which have more than 90% of cis 1,4 bonds, polyisoprenes, butadiene-styrene copolymers and in particular those which have a styrene content of between 5% and 50% by weight and more particularly between 20% and 40% by weight, a 1,2 bond content of the butadiene portion of between 4% and 65%, a trans 1,4 bond content of between 30% and 80%, those which have an overall content of aromatic compound of between 5% and 50% and a glass transition temperature (Tg) of between 0° C. and -80° C., and particularly those which have a styrene content of between 25% and 30% by weight, a content of vinyl bonds in the butadiene portion of between 55% and 65%, a trans 1,4 bond content of between 20% and 25% and a glass transition temperature of between -20° C. and -30° C.
In the case of butadiene-styrene-isoprene copolymers, those which are suitable have a styrene content of between 5 and 50% and more particularly between 10% and 40%, an isoprene content of between 15% and 60% by weight and more particularly between 20% and 50 by weight, a butadiene content of between 5 and 50% and more particularly between 20% and 40% by weight, a content of 1,2-units in the butadiene portion of between 4% and 85%, a content of trans 1,4 units in the butadiene portion of between 6% and 80%, a content of 1,2 plus 3,4-units in the isoprene portion of between 5% and 70% and a content of trans 1,4 units in the isoprene portion of between 10% and 50%.
The elastomer may, of course, be coupled and/or starred or else functionalized with a coupling and/or starring or functionalizing agent. The elastomer may also be natural rubber or a blend based on natural rubber with any synthetic, especially diene-based, elastomer.
Besides one or more elastomers and the silica, the compositions in accordance with the invention contain all or part of the other constituents and additives usually employed in rubber mixes, like plasticizers, pigments, antioxidants, antiozonant waxes, a crosslinking system based either on sulfur, sulfur donors and/or on peroxide and/or on bismaleimides, vulcanization accelerators, extender oils, one or more silica-coating agents such as alkoxysilanes, polyols, amines, and the like.
The compositions in accordance with the invention may contain between 0.5 and 15 parts by weight of functionalized polyorganosiloxane compound(s) and from 0.2 to 8 parts by weight of functionalized organosilane compound(s).
In a way which could not be foreseen by a person skilled in the art, it has been discovered that the rubber compositions in accordance with the invention and including a reinforcing additive consisting of at least one linear or cyclic functionalized polyorganosiloxane and at least one organosilane compound exerting a rubber/silica bond, make it possible:
to employ high ratios of organosilane agents belonging to the mercaptosilane class, without incurring a penalty in terms of "scorch safety" and without perturbing the processing of the compositions,
to increase appreciably the effectiveness of the organosilane agents and particularly those of the mercaptosilane type,
to prepare silica-filled vulcanizates exhibiting an improved hysteresis, which makes these compositions particularly useful for the manufacture not only of tires but also of semifinished products, especially of treads, of underlinings, of sidewall rubbers or of rubbers intended to adhere to textile or metal reinforcements,
to obtain good processing properties in the raw state by virtue of a reduction in viscosity,
to facilitate the adjustment of the content of rubber/silica reinforcement agent (in particular in the case of low contents), through the use of two products instead of one, without necessarily being penalized in terms of processing and scorch safety,
in general, to prepare silica-filled vulcanizates exhibiting an advantageous compromise of properties when compared with the solutions already known in the art.
The maximum beneficial effect is obtained when the highly dispersible silica forms all of the reinforcing filler. A beneficial effect is also obtained when the silica is employed predominantly or blended with conventional precipitated silicas, or else with carbon black: carbon blacks which are suitable are any carbon blacks, especially all the commercially available blacks and preferably the HAF, ISAF, SAF and other blacks conventionally employed in tires and particularly in tire treads. As nonlimiting examples of such blacks may be mentioned the blacks N 134, N 115, N 234, N 339, N 347, N 375, and the like.
The quantity of carbon black which is present may vary within wide limits, it being understood, however, that the improvement in the properties will be proportionally greater the higher the silica content present. The quantity of carbon black which is present is preferably equal to or lower than 200% of the quantity of silica present in the composition.
Another subject-matter of the invention is a process for improving the hysteretic properties of rubber compositions including silica as reinforcing filler which are intended for the manufacture of tire casings and of semifinished products for tire casings, which consists in adding to the compositions a reinforcing additive consisting of the addition and the mixing, in any order, of at least one functionalized polyorganosiloxane compound containing, per molecule, at least one functional siloxy unit capable of bonding chemically and/or physically with the surface hydroxyl sites of the silica particles and at least one functionalized organosilane compound containing, per molecule, at least one functional group capable of bonding chemically and/or physically with the polyorganosiloxane and/or the hydroxyl sites of the silica particles and at least one other functional group capable of bonding chemically and/or physically to the chains of polymer(s).
Another subject-matter of the invention is a process making it possible to delay substantially the premature vulcanization (scorching) of diene rubber compositions intended for the manufacture of tire casings and of semifinished products for tire casings, including silica as reinforcing filler.
The process according to the invention consists in adding and incorporating into the rubber of the composition a reinforcing additive for establishing an elastomer/silica bond, consisting of a functionalized polyorganosiloxane compound containing, per molecule, at least one functional siloxy unit capable of bonding chemically and/or physically with the surface hydroxyl sites of the silica particles and at least one functionalized organosilane compound containing, per molecule, at least one functional group capable of bonding chemically and/or physically with the polyorganosiloxane and/or the hydroxyl sites of the silica particles and at least one other functional group capable of bonding chemically and/or physically to the chains of polymer(s).
The two constituents of the reinforcing additive may be added in any order, that is to say simultaneously or one after the other; the functionalized polyorganosiloxane compound is preferably added first before the addition of the organosilane compound. It is also possible to react the polyorganosiloxane with the silica before the latter is mixed with the rubber. This process enables the mercaptosilanes to be used on industrial scale by delaying the appearance of the phenomenon of scorching of the composition containing silica as reinforcing filler. This effect of delaying the appearance of the scorching phenomenon offers an advantage in the case of the mercaptosilanes, as well as in the case of other organosilane compounds, in the sense that it makes it possible to decrease the quantity of organosilane, which is generally very costly, needed without significantly affecting the compromise of the composition in terms of scorch safety, of ease of processing and of reinforcing power. The process according to the invention is thus capable of reducing the costs of manufacture.
The functionalized polyorganosiloxane compound acts as a covering agent, in contrast to a reinforcing function, when it is mixed with the silica in the presence of at least one elastomer forming part of the rubber composition used to manufacture the tire casing. In other words, the siliceous filler is covered with the organopolysiloxane compound(s).
The invention is illustrated, without any limitation being implied, by the examples which must not be taken to constitute a limitation of the scope of the invention. In the examples the properties of the compositions are evaluated as follows:
Mooney viscosity ML (1+4) at 100° C. measured according to standard AFNOR-NF-T43-005 (November 1980), entitled Mooney in the tables which follow.
Moduli of elongation at 300% (M 300), 100% (M 100): measurements performed in MPa according to standard AFNOR-NF-T46-002 (September 1988).
Tensile strength (TS) in MPa and elongation at break (EB) in %: measurements performed at 20° C. according to standard AFNOR-NF-T40-101 (September 1979)
Hysteretic losses (HL): measured by rebound at 60° C. on 6th impact and expressed in %.
Dynamic Shear Properties:
Measurements as a function of the deformation: performed at 10 Hertz with a crest-crest deformation ranging from 0.15% to 50%. The hysteresis is expressed by the measurement of tan δ at 7% deformation. The dynamic modulus (G) for the highest deformation level is expressed in N/m 2 . The measurements are performed according to ASTM standard D 2231-87;
Scorch Time: (T5) Expressed in Minutes.
Time needed to obtain an increase in the value of the consistometry index, expressed in "Mooney units", by 5 units above the minimum value measured in the case of this index. Measurements performed at 130° C. according to standard AFNOR-NF-T43-005 (November 1980).
Rheometric Characteristics:
The following values are deduced from the vulcanization curves:
Ts (0.2): time in minutes needed for the increase in the torque by 0.2 N m from the minimum Mooney ML (1+4)100 torque.
Tc (99): vulcanization time in minutes corresponding to 99% of the highest torque obtained.
The measurements are performed at 150° C. according to standard AFNOR-NF-T43-015 (August 1975).
DESCRIPTION OF THE DRAWINGS
FIGS. 1 to 4 show the vulcanization curves for various rubber compositions including various reinforcing additives. The vulcanization period of the compositions, expressed in minutes, is shown as the abscissa. The rheometric torque, expressed in decanewtons per meter (dN/m) is shown as the ordinate.
DESCRIPTION OF PREFERRED EMBODIMENTS
In the examples the contents of materials are expressed in phe: parts per hundred of elastomer by weight.
EXAMPLE 1
This example is intended to compare two rubber compositions which are identical with the exception of the covering additive which, in the case of test 1, the control test, is Dynasylan 3201 and, in the case of test 2, in accordance with the invention, consists of Dynasylan 3201 and the functionalized polyorganosiloxane (PMHS) corresponding to the formula (V-2) shown above. This functionalized PMHS is prepared as follows:
Into a 500 ml three-necked round bottom flask equipped with mechanical stirring, a thermometer and a dropping funnel are charged, under nitrogen atmosphere, 300 ml of ethanol predried on 3 angstrom molecular sieve and 10 μl of Karstedt catalyst (10% in hexane). The mixture is stirred and dropwise addition of polymethylhydrosiloxane (40 g, dp n =50) is started. The rate of addition of the Si-H fluid is adjusted to control the flow rate of hydrogen and the exothermicity of the reaction. At the end of addition the mixture is left stirring for one hour. 36 g of 1-octene are then added dropwise. After addition the reaction mixture is heated to 60° C. until all the Si-H functional groups have been consumed. The excess of alcohol and of octene is then evaporated off. 87 g of clear and slightly colored oil are recovered. NMR analysis shows the following structure (NMR): ##STR20##
The diene polymers are processed by thermomechanical working in two stages in an internal mixer, which last 5 and 4 minutes respectively, with a mean blade speed of 45 rev/min, until a maximum drop temperature of 160° C. is reached, followed by a finishing stage performed at 30° C. on an external mixer, under the following formulations:
TABLE 1______________________________________Composition No. 1 2______________________________________SBR (1) 96 96 PB (2) 30 30 Silica (3) 80 80 ZnO 2.5 2.5 Stearic acid 2 2 Antioxidant (4) 1.9 1.9 PMHS (5) 4.5 Dynasylan 3201 (6) 2.8 2 Aromatic oil 6 6 Sulfur 1.1 1.1 CBS (7) 2 2 DPG (8) 1.5 1.5______________________________________ (1): SBR which has 59.5% of 1,2 bonds, 23% of trans bonds, 26% of styrene incorporated and extended with 37.5% of oil; (2): PB which has 4.3% of 1,2 bonds, 2.7% of trans bonds, 93% of cis 1,4 bonds (3): Zeosil 1165 MP silica from the company RhonePoulenc (4): N1,3-Dimethylbutyl-N-phenyl-para-phenylenediamine (5): Functionalized PMHS corresponding to the formula (V2) (6): Mercaptopropyltriethoxysilane marketed by the company Huls (7): NCyclohexyl-2-benzothiazylsulfenamide (8): Diphenylguanidine
The properties of the rubber compositions measured before curing (Mooney) and the rheograms at 150° C. are shown respectively in Table 2 and in FIG. 1.
TABLE 2______________________________________Composition No. 1 2______________________________________Properties before curing Mooney 137 90 T5 (min) 3.5 22.5______________________________________
In FIG. 1, curve C1 corresponds to the reference composition 1 with the mercaptosilane alone and curve C2 corresponds to the composition 2 in accordance with the invention. The scorch time results and the rheograms of FIG. 1 show that the invention allows the scorch safety to be considerably increased. In addition, the invention facilitates processing of the rubber compositions containing a mercaptosilane.
EXAMPLE 2
This example is also intended to show the need for, and the advantage of, employing a bonding agent simultaneously with a functionalized PMHS. Two compositions are produced which are identical with those of Example 1 with the exception of the contents of PMHS and Dynasylan 3201.
TABLE 3______________________________________Composition No. 3 4______________________________________SBR 96 96 PB 30 30 Silica 80 80 ZnO 2.5 2.5 Stearic acid 2 2 Antioxidant 1.9 1.9 Aromatic oil 6 6 PMHS 5 5 Dynasylan 3201 1.5 Sulfur 1.1 1.1 CBS 2 2 DPG 1.5 1.5______________________________________
The properties of the rubber compositions measured before and after curing are listed in Table 4.
TABLE 4______________________________________Composition No. 3 4______________________________________Properties before curing Mooney 75 88 T5 (min) >30 >30 Cure time at 150° C. in minutes 60 40 Properties after curing M100 0.68 1.5 M300 2.47 6.75 HL 41.7 24.6 EB 1040 580 TS 16.8 19.6 Dynamic properties tan δ 0.324 0.257______________________________________
The results show that composition 3, containing no mercaptosilane, has a low level of reinforcement. On the other hand, the results obtained with composition 4 make it possible to demonstrate that the use of the invention gives a higher and a satisfactory level of reinforcement and lower hysteresis levels without significantly penalizing the properties before curing and consequently the processing.
EXAMPLE 3
The aim of this example is to demonstrate the advantage of the invention when compared with the use, known in the art, of a combination including a bonding agent of mercaptosilane type and an alkylsilane.
Two compositions are produced which are identical with those of Example 1 with the exception of the contents of covering additive and of sulfur and, in the case of control composition 5, the addition of an alkylsilane.
TABLE 5______________________________________Composition No. 5 6______________________________________SBR 96 96 PB 30 30 Silica 80 80 ZnO 2.5 2.5 Stearic acid 2 2 Antioxidant 1.9 1.9 Aromatic oil 6 6 PMHS (9) 4 Dynasylan 3201 1.1 1.1 Si 216 (*) 4 Sulfur 2.4 2.4 CBS 2 2 DPG 1.5 1.5______________________________________ (9) Functionalized PMHS corresponding to the formula (V3) (*) Si 216: covering agent of raw formula C.sub.16 H.sub.33 Si(OEt).sub.3 marketed by the company Degussa
The results are listed in Table 6.
TABLE 6______________________________________Composition No. 5 6______________________________________Properties before curing Mooney 80 78 T5 (min) 15 23 Cure time at 150° C. in minutes 40 40 Properties after curing M100 1.69 2.04 M300 5.89 7.52 HL 30.3 30.9 EB 540 480 TS 21.4 21.1 Dynamic properties tan δ 0.244 0.254______________________________________
Composition 6, in accordance with the invention, enables scorch times T5 to be obtained which are superior to those obtained with the composition in accordance with the state of the art, employing the combination of a mercaptosilane and of an alkylsilane, while facilitating the processing.
In addition, composition 6, in accordance with the invention, makes it possible to obtain, at equivalent contents of constituent materials, a reinforcement level which is far superior to that of the control composition.
EXAMPLE 4
This example is intended to demonstrate that the invention makes it possible to introduce into the rubber compositions large quantities of organosilanes which have a mercapto functional group. The compositions thus prepared remain easy to process and exhibit a satisfactory scorch safety.
Three compositions in accordance with the invention are prepared, which are identical with those of Example 1 with the exception of the quantities of mercaptosilane, which vary.
TABLE 7______________________________________Composition No. 7 8 9______________________________________SBR 96 96 96 PB 30 30 30 Silica 80 80 80 ZnO 2.5 2.5 2.5 Stearic acid 2 2 2 Antioxidant 1.9 1.9 1.9 Aromatic oil 6 6 6 PMHS 4.5 4.5 4.5 Dynasylan 3201 1 1.5 2 Sulfur 1.1 1.1 1.1 CBS 2 2 2 DPG 1.5 1.5 1.5______________________________________
The properties of the rubber compositions measured before and after curing are listed in Table 8.
TABLE 8______________________________________Composition No. 7 8 9______________________________________Properties before curing Mooney 87 88 91 T5 (min) >30 >30 >30 Cure time at 150° C. 40 40 40 in minutes Properties after curing M100 1.51 1.49 1.54 M300 6.34 6.75 7.32 HL 25.9 24.6 23.2 EB 620 590 510 TS 19.8 19.3 17.7 Dynamic properties G 1.58 × 10.sup.6 1.58 × 10.sup.6 1.52 × 10.sup.6 tan δ 0.263 0.255 0.24______________________________________
The results show that the invention allows the mercaptosilane content to be increased without incurring any penalty in terms of scorch safety, which remains satisfactory, and of processing of the compositions.
Consequently, the invention makes it possible to prepare rubber compositions with high contents of bonding agent of the mercaptosilane class, in contrast to what was possible according to the prior state of the art.
EXAMPLE 5
This example is intended to demonstrate the advantage of the invention in relation to the use of Si 69 (bis(3-triethoxysilylpropyl) tetrasulfide) marketed by the company Degussa, which is considered to be the product giving the best compromise in the case of compositions including silica as reinforcing filler, in terms of scorch safety, ease of processing and reinforcing power.
Two compositions are prepared which are identical with those of Example 1 with the exception, in the case of control composition 10, of the use of Si 69 alone as reinforcing additive and, in the case of composition 11, in accordance with the invention, of the Dynasylan 3201 content.
TABLE 9______________________________________Composition No. 10 11______________________________________SBR 96 96 PB 30 30 Silica 80 80 ZnO 2.5 2.5 Stearic acid 2 2 Antioxidant 1.9 1.9 Aromatic oil 6 6 PMHS 4.5 Dynasylan 3201 1.5 Si 69 6.4 Sulfur 1.1 1.1 CBS 2 2 DPG 1.5 1.5______________________________________
The properties of the rubber components measured before and after curing are listed in Table 10.
TABLE 10______________________________________Composition No. 10 11______________________________________Properties before curing Mooney 82 88 T5 (min) 25 >30 Cure time at 150° C. in minutes 40 40 Properties after curing M100 1.56 1.49 M300 6.97 6.75 HL 26.4 24.6 EB 560 590 TS 19.5 19.3 Dynamic properties tan δ 0.299 0.255______________________________________
It is found that the invention makes it possible to improve the scorch safety and to decrease the hysteresis without substantially penalizing the other properties.
EXAMPLE 6
This example is intended to demonstrate that the beneficial effect of the invention is also obtained with rubber compositions based on natural rubber which are reinforced with silica. Three compositions are prepared according to the formulations shown in Table 11.
TABLE 11______________________________________Composition No. 12 13 14______________________________________Natural rubber 100 100 100 Silica (3) 50 50 50 ZnO 5 5 5 Stearic acid 2 2 2 Antioxidant (4) 1.9 1.9 1.9 PMHS (5) 2.5 PMHS (9) 2.5 A 189 (10) 3 1.5 1.5 Sulfur 1.3 1.3 1.3 CBS (7) 2 2 2 DPG (8) 1.1 1.1 1.1______________________________________
The materials (3) (4) (5) (7) and (8) are identical with those in Example 1. Material (9) is identical with that of Example 3.
(10): γ-Mercaptopropyltrimethoxysilane marketed by the company OSI.
Composition 12 is a control composition containing only one mercaptosilane compound, the rheogram of which is shown in FIG. 2 by curve C3; compositions 13 and 14 are in accordance with the invention and their rheograms are shown in FIG. 2 by curves C4 and C5 respectively. The properties of the rubber compositions measured before curing and after curing and the rheograms at 150° C. are shown in Table 12 and in FIG. 2 respectively.
TABLE 12______________________________________Composition No. 12 13 14______________________________________Properties before curing Mooney 102 54 53 T5 (min) 0 12.5 12 Rheometric characteristics Ts (0.2) min 0 4.5 4.5 Tc (99) (min) 5 11 11 Cure time at 150° C. in 20 20 minutes Properties after curing M100 Premature 1.77 1.79 M300 vulcanization 5.7 5.85 HL 15.2 14.6______________________________________
A considerable improvement in the scorch safety is observed throughout the measurements of the scorch time and of the rheometric characteristics. Furthermore, the invention makes it possible to improve the processing and to allow on industrial scale the production of compositions with a bonding agent of the mercaptosilane class.
EXAMPLE 7
Two compositions are produced which are identical with those of Example 5, except that in the case of composition 16, in accordance with the invention, the quantity of PMHS (5) is higher than in composition 11.
TABLE 13______________________________________Composition No. 15 16______________________________________SBR 96 96 PB 30 30 Silica 80 80 ZnO 2.5 2.5 Stearic acid 2 2 Antioxidant 1.9 1.9 Aromatic oil 6 6 PMHS 6 Dynasylan 3201 1.5 Si 69 6.4 Sulfur 1.1 1.1 CBS 2 2 DPG 1.5 1.5______________________________________
Composition 15 is a reference composition identical with composition 10 of Example 5, already known in the art, and capable of being used for producing a tire casing tread. The properties of the rubber compositions measured before and after curing are shown in Table 14.
TABLE 14______________________________________Composition No. 15 16______________________________________Properties before curing Mooney 82 86 T5 (min) 25 >30 Cure time at 150° C. in minutes 40 40 Properties after curing M100 1.56 1.59 M300 6.97 7.5 Hysteresis 26.4 22.3 EB 560 530 TS 19.5 18.1 Dynamic properties G 3.67 × 10.sup.6 1.97 × 10.sup.6 tan δ 0.299 0.231______________________________________
The results show that the composition in accordance with the invention makes it possible to obtain properties before curing which are similar to those obtained with Si 69 and that, after curing, it has a reinforcement level identical with that of reference composition 15, while the hysteresis and tan δ levels are considerably lower, and this makes such a composition particularly suitable for forming part of the constitution of semifinished products, especially treads, capable of giving tire casings which have a reduced rolling resistance.
EXAMPLE 8
This example shows the advantage of a rubber composition in accordance with the invention and crosslinking with sulfur, for coating and adhering to a metal reinforcement intended to be employed in a tire casing.
Three compositions are produced according to the formulations described in Table 15. Composition 17 is a reference composition containing no elastomer/silica reinforcement additive. Composition 18 is also a control composition containing only γ-mercaptopropyltriethoxysilane. Composition 19 is in accordance with the invention.
TABLE 15______________________________________Composition No. 17 18 19______________________________________Natural rubber 100 100 100 Silica (12) 50 50 50 ZnO 4 4 4 Stearic acid 1 1 1 Antioxidant (4) 2 2 2 Cobalt salt (13) 0.7 0.7 0.7 PMHS (11) 2.5 Dynasylan 3201 (6) 1 1 Sulfur 4.5 4.5 4.5 CBS (7) 0.8 0.8 0.8 DPG (8) 0.8 0.8 0.8______________________________________ Materials (4), (6), (7) and (8) are the same as those in Example 1 (11): Functionalized PMHS corresponding to the formula (V4) (12): Ultrasil VN 2 silica marketed by the company Degussa (13): Cobalt naphthenate
The properties of the rubber compositions measured before and after curing at 150° C. are shown, respectively, in Table 16.
TABLE 16______________________________________Composition No. 17 18 19______________________________________Properties before curing Mooney 94 82 74 Cure time at 150° C. in minutes 35 35 35 Properties after curing M100 1.69 2.22 2.06 M300 4.08 6.36 5.91 HL 20.7 17.2 14.5 EB 590 570 510 TS 22.1 23.6 22.1______________________________________
It is found that the composition in accordance with the invention has processing properties in the unvulcanized state which are superior to those of the compositions according to the prior art. In other words, the use of the reinforcing additive according to the invention allows the Mooney viscosity to be improved.
It is also found that the composition in accordance with the invention has a hysteresis which is clearly improved without incurring a penalty in the reinforcing properties and the mechanical properties of the composition.
EXAMPLE 9
The aim of this example is to show that a reinforcing additive including polyorganosiloxanes which are functionalized "at the chain end" can also be employed within the scope of the invention. Three compositions are produced according to the formulations described in Table 17.
The compositions 15 and 20 are control compositions in accordance with the state of the art, employing only a bonding agent. Their rheograms are shown in FIG. 3 by curves C6 and C7 respectively. Composition 21 is in accordance with the invention and the rheogram is shown in FIG. 3 by curve C8.
TABLE 17______________________________________Composition No. 15 20 21______________________________________SBR (1) 96 96 96 PB (2) 30 30 30 Silica (3) 80 80 80 ZnO 2.5 2.5 2.5 Stearic acid 2 2 2 Antioxidant (4) 1.9 1.9 1.9 Aromatic oil 6 6 6 PS 340 (14) 4.5 Dynasylan 3201 (6) 1.8 1.8 Si 69 6.4 Sulfur 1.1 1.1 1.1 CBS (7) 2 2 2 DPG (8) 1.5 1.5 1.5______________________________________
Materials (1), (2), (3), (4), (6), (7), (8) and Si 69 are the same as those in Example 1.
(14): PS340 polydimethylsiloxane functionalized with OH at chain ends, marketed by ABCR.
The properties of the rubber compositions measured before and after curing at 150° C., and the rheograms produced at 150° C. are shown in Table 18 and in FIG. 3 respectively.
TABLE 18______________________________________Composition No. 15 20 21______________________________________Properties before curing Mooney 82 105 90 Rheometric characteristics Ts (0.2) 5 0 8 Tc (99) 34 27 30 Cure time at 150° C. in minutes 40 40 40 Properties after curing M100 1.56 1.68 2.44 M300 6.97 4.38 10.92 HL 26.4 35 19.8______________________________________
Throughout the Mooney viscosity results we see that the invention makes it possible to facilitate the processing of the rubber compositions comprising a high content of reinforcing agent of the mercaptosilane type.
It is also seen that the composition in accordance with the invention makes it possible to obtain rigidities (M100 and M300) which are clearly superior to those of the reference compositions and that the hysteretic properties are clearly improved in relation to those measured in the case of the control compositions 15 and 20.
Furthermore, the rheometric characteristics, and the curves in FIG. 3, show that the invention makes it possible to employ a mercaptosilane, because it gives rise to a large increase in the scorch safety of the composition.
EXAMPLE 10
The aim of this example is to demonstrate that the rubber compositions in accordance with the invention which are reinforced at the same time with silica and with carbon black have an improved processing.
2 compositions are produced according to the formulations described in Table 19. Composition 22 is a control composition, while composition 23 is in accordance with the invention.
TABLE 19______________________________________Composition No. 22 23______________________________________SBR (15) 137.5 137.5 Silica (3) 40 40 Black N 234 15 15 ZnO 3 3 Stearic acid 2 2 Antioxidant (4) 1.5 1.5 PMHS (11) 2.5 Dynasylan 3201 (6) 1 1 Sulfur 1.4 1.4 CBS (7) 1.4 1.4______________________________________
Materials (3), (4), (6) and (7) are the same as those in Example 1.
Material (11) is that employed in Example 8.
(15): Emulsion SBR (Cariflex 1712) which has 16% of 1,2 bonds, 72% of trans bonds and 23.5% of incorporated styrene, extended with 37.5% of oil and marketed by Shell.
The properties of the rubber compositions measured in the raw state are shown in Table 20.
TABLE 20______________________________________Composition No. 22 23______________________________________Properties before curing Mooney 114 97 TS (min) >30 >30______________________________________
It is found that the composition in accordance with the invention still has a Mooney viscosity which is lower than that of the control composition when the reinforcing filler in the composition is a blend of carbon black and of silica.
EXAMPLE 11
This example is intended to demonstrate that the compositions in accordance with the invention have improved properties with a reduced Si 69 content when it is employed in combination with a functionalized polyorganosiloxane.
Two compositions are produced according to the formulations described in Table 21. Composition 24 is a control composition in accordance with the state of the art. Composition 25 is in accordance with the invention.
TABLE 21______________________________________Composition No. 24 25______________________________________SBR (1) 96 96 PB (2) 30 30 Silica (3) 80 80 ZnO 2.5 2.5 Stearic acid 2 2 Antioxidant (4) 1.9 1.9 Aromatic oil 6 6 PMHS (11) 4.5 Si 69 2 2 Sulfur 1.1 1.1 CBS (7) 2 2 DPG (8) 1.5 1.5______________________________________
Materials (1), (2), (3), (4), (7) and (8) are the same as those employed in Example 1 and material (11) is that employed in Example 8.
The properties of the rubber compositions measured before curing and the rheometric characteristics obtained at 150° C. are shown in Table 22.
FIG. 4 contains the rheograms of compositions 24 and 25, shown by curve C9 and curve C10 respectively.
TABLE 22______________________________________Composition No. 24 25______________________________________Properties before curing Mooney 113 65 T5 (min) 6 >30 Rheometric characteristics (150° C.) Ts (0.2) (min) 0 15 Tc (99) (min) indeterminate 35______________________________________
The results show that the invention makes it possible to obtain rubber compositions which are highly filled with silica and which have an excellent processability, but with a reduced Si 69 content, and this makes it possible to achieve savings in the production costs of compositions containing silica as a reinforcing filler without incurring any penalty in the compromise in terms of scorch safety.
EXAMPLE 12
This example is intended to demonstrate that the compositions in accordance with the invention have properties which are equivalent to those obtained when Si 69 is employed, but with an overall reinforcing additive content which is clearly decreased.
Two compositions are produced according to the formulations described in Table 23. Composition 15, already described in Example 7, is in accordance with the state of the art;
composition 27 is in accordance with the invention.
TABLE 23______________________________________Composition No. 15 27______________________________________SBR (1) 96 96 PB (2) 30 30 Silica (3) 80 80 ZnO 2.5 2.5 Stearic acid 2 2 Antioxidant (4) 1.9 1.9 Aromatic oil 6 6 PS 340 (14) 2.5 Dynasylan 3201 (6) 1.1 Si 69 6.4 Sulfur 1.1 1.1 CBS (7) 2 2 DPG (8) 1.5 1.5______________________________________
Materials (1), (2), (3), (4), (6), (7), (8) and (14) are the same as those in the preceding examples.
The properties of the rubber compositions measured before and after curing at 150° C. are shown in Table 24.
TABLE 24______________________________________Composition No. 15 27______________________________________Properties before curing Mooney 82 90 T5 (min) 25 >30 Cure time at 150° C. in minutes 40 40 Properties after curing M100 1.56 1.62 M300 6.97 6.75 HL 26.4 26.2 EB 560 600 TS 19.5 21.8______________________________________
The results show that the composition in accordance with the invention makes it possible to obtain properties before curing which are close to those obtained with Si 69 and that after curing it has a reinforcement level identical with that of the control composition No. 15, but with an overall reinforcing additive content which is clearly lower (3.6 phe against 6.4 phe), which makes it possible to achieve savings in the costs of the composition, without incurring a penalty in the compromise of the properties.
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Rubber composition intended for the manufacture of tire casings which havemproved hysteretic properties and scorch safety, based on at least one elastomer and silica by way of reinforcing filler enclosing a reinforcing additive consisting of the mixture and/or the product of in situ reaction of at least one functionalized polyorganosiloxane compound containing, per molecule, at least one functional siloxy unit capable of bonding chemically and/or physically to the surface hydroxyl sites of the silica particles and at least one functionalized organosilane compound containing, per molecule, at least one functional group capable of bonding chemically and/or physically to the polyorganosiloxane and/or the hydroxyl sites of the silica particles and at least one other functional group capable of bonding chemically and/or physically to the polymer chains.
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FIELD OF THE INVENTION
Generally, this invention relates to the field of games. More specifically, this invention is a bag toss game which utilizes two target boards. During storage, the target boards interlock forming an enclosed compartment between them for the storage of the tossing bags and any other items required.
BACKGROUND OF THE INVENTION
There appears to be an almost universal enjoyment by participants of tossing type games, be they formal games such as horse shoes, or something as simple as throwing a rock into the water then trying to land other rocks within the same area. Thus, the field of games is replete with different types of tossing games and new variations on this general concept are myriad. Occasionally, one such variation is able to combine the basic enjoyment of a tossing game with a new type of system or device which in some way either alters the play of the game, or improves the convenience of using the game to a point that the game becomes widely accepted.
For example, one well known game utilizes over sized darts which are weighted in order to stick in the ground when thrown, which darts are combined with two single ring targets with the play following somewhat similar to that of horse shoes. Two problems with this type of dart toss game are easily recognized. Namely, the obvious threat to safety and the difficulty of having to store the multiplicity of parts used in the game for future use.
Other games have combined this basic toss concept with yet other known games such as tic-tac-toe. In a game such as this, a bean bag or the like is often thrown onto a target and by any one of a variety of methods and an "x" or "o" designation is recorded where the bag has landed to come to rest. The goal of such games being similar to tic-tac-toe in that the user tries to align the same designations in a row until there is a connection made between one side of the target board and the other side. While such a game overcomes the safety threat posed by the dart toss game, the problem with storing the target and bags still remains.
Thus, virtually everyone having such a toss game has experienced the frustration of being unable to locate some of the parts of the game, the most common problem being a lack of a full compliment of toss items. Eventually, the toss items disappear and statements such as "you can only use three of yours because I can't find my fourth one" continue until the numbers eventually decrease to two or one. Any reduction in the number of toss items makes the game more difficult as the players must more frequently retrieve the toss items. Finally, the entire game is either left unused since "I can't find all the pieces" or the game is simply discarded.
To appreciate what the effect would be of having a toss game where one does not have to be worried about loosing the various parts, one need only consider the various games available at amusement centers or bazaars. Many of these include toss games such as the throwing of rings, balls or bean bags. Such games are very popular at these events, since they appeal to the natural tendency to play toss type games and also because the participant can use his or her skill in these tossing games without concern of the loss or gathering up of the various parts and pieces. Thus, it became evident to me that to have a tossing game which utilizes not only basic toss concepts but incorporates game variations as well as a simple yet effective storage mechanism, would not only provide a great deal of enjoyment but would also avoid much frustration.
In addition to the above stated factors many toss games are made for use in a specific setting. For example, some such games are solely for indoor use and are not constructed in a manner suitable for use out of doors. Or, alternatively, if the indoor game is used out of doors the various parts may become almost irreversibly soiled in which case the game becomes designated strictly as an outdoor game to avoid the use of these soiled items within the home. Still other games are seasonal or require a specific type of seasonal play surface. Summer time for example, lends itself to the use of games which are suitable for play as a water sport. However, such games might not be suitable for play outside of their aquatic environment.
Based upon a recognition of these problems and consideration of various solutions the applicants have developed the subject invention which combines basic toss concepts with a unique target combination. In addition, the subject invention solves the problem of storing the various toss items and the targets while providing versatile play pieces suitable for use not only indoors and outdoors but also as a water sport. Accordingly, applicant believes that the subject invention is a significant improvement over prior toss games and will obtain wide acceptance and provide much satisfaction and enjoyment to its users.
SUMMARY OF THE INVENTION
The subject matter of this invention is directed toward a new toss game having targets that engage each other for easy transportation of the target boards while also forming an enclosed storage compartment that acts as a receptacle for whatever type of tossing item used. The invention is blow molded out of plastic so as to form hollow supports which enable the toss game to float, and with rubber toss bags, it may be used as a water sport. When the boards are separated and used individually the variation in the support sizes will provide different buoyancies such that the boards will float on somewhat of an angle for easier viewing of the board and more simplified hand, eye coordination. When the target boards are engaged together back to back they still float, however, the different buoyancy of each target board support offsets the other providing a substantially horizontal game surface, more difficult distance evaluation and greater hand, eye coordination.
The subject invention accomplishes these purposes through the use of two target boards having a relatively flat top surface onto which the tossing bags may be thrown. Each target board has a hole through the center of the board that serves as a bulls eye and may be used in various ways during the play of the game. Concentric ridges on the top of the boards prevent the toss bags from sliding off of the targets. On the bottom of the boards are two sets of supports, one set of which is placed inward around the periphery of the hole in the middle of the game board, with the other set placed outwardly under and around the outer portion of the game board. The outer supports are higher toward one end of the board and lower toward the other end such that the boards are tilted when resting on the supports. For storage, the boards nest bottom to bottom with inner supports abuting each other, and the outer supports abuting such that the higher portions of the outer support abut the lower portions of the outer support of the opposing board. This creates a completely enclosed channel between the boards for storage of the tossing bags.
The target boards are blow molded of a plastic material in a manner which provides for the forming of hollow spaces within the supports. The amount of hollow space is sufficient to float the board in water. Since the outer support has different sizes with incomminently different amounts of air space, the larger portions which have greater air space will also be more buoyant thus raising that end of the target board so that the board remains angled even in the water. Alternatively, when used as a water sport the participants are not above the target as much as they are when the game is placed on the ground. This adds another dimension to the play as a type of hand, eye coordination is altered since the players are on a more similar plane with the target board and an overhand toss must be used. The target boards can be arranged to add an additional variation in that the boards may be nested back to back before being put in the water. The corresponding higher and lower portions of the outer supports cancel any variation in buoyancy so that the target floats substantially flat on the water. Thus, the players do not have a clear view of the target surface and therefore, the accurate tossing of the bags requires a greater exercise of depth perception and again a varied degree of hand/eye coordination. While the above is a summary of some of the characteristics and advantages of the subject invention man of the subtleties of the game such as the manner of play, ease of storage and versatility will only become truly evident and be fully appreciated through the actual use of the game.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of one of the target boards;
FIG. 2 is a cross sectional view taken along lines 2--2 of FIG. 1; and
FIG. 3 is a cross sectional view similar to FIG. 2 but showing two target boards locked bottom to bottom in the nesting position.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a target board generally designated as 10 which has a top surface 12. Centrally located through the board is an opening 14 which serves as the board bulls eye. The top surface 12 of the target board 10 is divided into a plurality of concentric rings 16 which rings are separated from one and other by ridges 18 which raise slightly above the top surface. The ridges 18 in my preferred embodiment are approximately 1/32 to 1/64 of an inch high and help prevent the rubber tossing bags 20 from sliding over the top surface. The tossing bag 20 has a cap 22 for altering the contents of the bag. In my preferred embodiment the contents of the bag is a combination of water and menthol cellulose which combine to form a jelly-like filling. Depending on the proportions of water and menthol cellulose the consistency of the gel-like filling can be varied to obtain different bag characteristics. For scoring purposes a predetermined number of concentric rings 16 may make up a section having a predetermined value. If preferred, each concentric ring can have a designated value which increases as one moves closer toward the opening 14.
On opposite sides of the board are notches 24 each of which has a peg 26 which extends upwardly toward the top surface of the board. If desired, one of the notches 24 on each board can be narrower at their opening than the elastic band 38, thus, securing the band within the notch at all times to assure that the bands 38 are not misplaced during play.
FIG. 2 is a side elevational view taken along lines 2--2 of FIG. 1 and showing the ridges 18 which in my preferred embodiment are approximately 1/32 to 1/64 of an inch above the top surface 12. The bottom surface 28 has an inner support ring 30 which is about the opening 14 and outer ring support 32 which extends around beneath the outer portion of the board when rested on a playing surface would be angled since outer support ring has a higher or larger portion 33 toward one side of the board and a smaller or lower portion 35 toward the other side of the board. The configuration of the outer support is essentially circular with the higher portion 33 extending 180° of the circle. When nested together the outer surface of the higher portion 33 of the first board abuts the inner surface of the lower portion 35 on the second board. Conversely, the outer surface of the higher portion 33 of the second board abuts the inner surface of the lower portion 35 of the first board. Also, the slopping portions of the outer supports on each board also engage each other. In the manner the nested boards are prevented from either slipping or rotating relative to each other. The slopping portions of the board are also beneficial when the board is used in the water. In this usage, the board when used separately floats at an angle and the sloped portions helps stabilize the board inhibiting rotation of the board in the water. In manufacture, the boards are blow molded such that the supports 30 and 32 are hollow as at 34 such that the entire target board is buoyant in water and floats at an angle similar to the angle created when the board is placed on a solid playing surface.
When placed bottom to bottom the board's nest as shown in FIG. 3 with the larger portion of the outer support 32 nesting against the smaller portion of the outer support 32 of the other board. Similarly, the inner supports 30 abut each other thus forming a circular, totally enclosed storage compartment or sealed container 36 for holding the tossing bags 20. The enclosure of the compartment must be sufficient to prevent the tossing bags 20 from exiting the compartment irrespective of the positioning of the board during storage.
The target boards 10 are secured in this nesting position by means of elastic bands 38 which are secured over opposing pegs or stanchions 26 to secure the nested target boards 10 in the storage position. When used, the target boards 10 are disengaged by releasing the elastic bands 38 from their respective pegs 26. The boards are then separated approximately 25 feet and set on the supports 30 and 32 which results in the angling of the top surface of the board which boards are located to angle downwardly toward each other. The target boards in my preferred embodiment are 36 inches in diameter and the game includes eight tossing bags 20, four being of one color and the other four being of a different color. For scoring purposes the outer five concentric rings form a section which is given a one point designation. The remaining inner rings have a two point designation with the opening 14 having a three point score for tossing bags which overhang the hole or pass therethrough. Teams begin by alternately throwing the tossing bags 20 one at a time onto one of the target boards 10. The total points are added and the team scoring the most points receives credit for the difference between their score and the score of the other team. Play continues until one of the teams reaches a total score of 21 points. In an alternate approach the first team to direct one of the toss bags 20 through the opening 14 cancels all of the scores on the board and receives an additional three points.
If preferred the targo boards can be used in a pool with the target boards being used either separately so that they float at an angle or in their nesting position as shown in FIG. 3 which will cause the target board to float substantially flat in the water thus making the landing of a toss bag on the top surface 12 more difficult. Because the game can be used in the water the tossing bags in my preferred embodiment are made of rubber and as previously stated, the contents of the tossing bags can be varied so that they will float.
It should be appreciated that other methods of play are possible and that variations may be made without departing from the invention, the scope of which should only be limited by the appended claims.
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In a bag tossing game nesting target boards which form an enclosed compartment for the storage of tossing bags. Supports on the bottom side of the target boards support the target boards in an upright and angle position and provide buoyancy for use of the target boards in water. Ridges on the top surface of the target boards reduce the slippage of the tossing bags off of the target board surface during play.
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REFERENCE TO RELATED APPLICATIONS
[0001] This is a U.S. national stage of application No. PCT/EP2012/069604 filed 4 Oct. 2012. Priority is claimed on German Application No. 102011084096.6 filed 6 Oct. 2011, the content of which is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to an adapter for an assembly having a valve and a positioner, where the valve includes a first interface and the positioner includes a second interface corresponding thereto, which are each configured for tube-less and pipe-less connection of the valve to the positioner in accordance with the guideline VDI/VDE 3847.
[0004] 2. Description of the Related Art
[0005] In order to control process valves, use is frequently made of pneumatic actuating drives (i.e., positioners), in which a diaphragm acting on an actuating element, such as on a closing element of a control valve, has pressure applied to it with the aid of a gaseous medium, for which in this application the general term “air” will be used, and is thus deflected. The application of a variable pressure to the diaphragm can be performed on one side, where the diaphragm is loaded by a spring on the other side, or it can be performed on both sides, with different pressures on the two sides of the diaphragm generating a drive force. The control of the pressures is performed via an electro-pneumatic position controller, in which an electrically actuated valve distributes feed air under pressure to the two sides of the diaphragm in the actuating drive via two air exhaust connections, depending on the activation.
[0006] EP 1 632 679 A1 discloses an electro-pneumatic position controller, in which a valve for distributing compressed air to two air exhaust connections can be employed in two different installation positions, where control air connections of the valve are each connected in an aligned manner to another of the two air exhaust connections in the two installation positions.
[0007] U.S. Pat. No. 6,354,327 B1 describes an assembly having an electro-pneumatic position controller and a pneumatic drive, in which a pneumatic switch is inserted between position controller and drive in order to permit a manual intervention.
[0008] The guideline VDI/VDE 3847 describes an additional interface between the drive of a positioner and position controller. Particular attention was directed to the mounting of the position controller being suitable for high vibration and shock loading and for pipe-less solenoid valve mounting in accordance with VDI/VDE 3845. The basis of the concept is the mounting of the position controller from the front on a vertical surface of the bonnet, which is provided with air ducts and fixing threads and a coding pin. Via the air ducts, both the feeding of the feed air and the connection to single-acting or double-acting drives are performed. As a result, replacement of the position controller is possible without disassembling existing feed air or control air lines. On the same side of the bonnet, at the back, a second vertical surface is provided, is likewise provided with air ducts and fixing threads and can also be used as a second interface for tube-less and pipe-less mounting of a solenoid valve. The connecting surfaces for the solenoid valve and position controller are optionally a fixed constituent part of the bonnet or can be implemented via a separate connecting block fixed to the bonnet. Since, in the aforementioned guideline, only the minimal size of the connecting surface, the position of the threaded holes, of a dowel pin and the inlet and outlet openings of air ducts are defined, but not a clearance which has to be provided in the area of the second interface for the mounting of the solenoid valve, there is the problem that, in the case of some drives, it is possible for a collision to occur between the solenoid valve and, for example, the head of the drive, if an attempt is made to mount the solenoid valve on the second interface when there is inadequate clearance.
SUMMARY OF THE INVENTION
[0009] It is therefore an object of the invention to provide an adapter by which the mounting of a valve, i.e., a solenoid valve, on the interface of a positioner, provided for the purpose in accordance with guideline VDI/VDE 3847, is made easier.
[0010] In order to achieve this object, the novel adapter of the type mentioned at the beginning has the features specified in the characterizing part of claim 1 . Advantageous developments are described in the dependent claims.
[0011] This and other objects and advantages are achieved in accordance with the invention by providing an adapter which is advantageously installed between a valve and positioner to provide the possibility to variably adjust the position of the valve relative to the positioner. The adapter can be mounted on an existing interface that is implemented in accordance with guideline VDI/VDE 3847, and can therefore be used universally. Specific adapters, which have to be constructed as a special solution for a specific application, are normally no longer required.
[0012] A particularly simple and robust embodiment of the adapter can be obtained if, via the adapter, the rotation of the valve with respect to the positioner is variably adjustable. An adapter of this type can be implemented with comparatively little effort in an embodiment that is suitable for high vibration and shock loading. For the implementation thereof, substantially as few as two adapter parts, which are rotatable relative to each other to adjust the rotation, are advantageously sufficient. For each air duct to be led via the adapter, an annular duct arranged substantially concentrically with respect to the axis of rotation can be provided between the two adapter parts, which is delimited by the latter. In each case, a feed duct in the two adapter parts produces the connection of the annular duct to the two pneumatic interfaces of the adapter. As a result of the virtually continuous possibility of rotation through virtually 360°, achieved in this way, in most cases the above-described collision problem can be avoided.
[0013] Special solutions for fixing a solenoid valve can thus normally be dispensed with.
[0014] If the two interfaces of the adapter are arranged parallel to each other, these can advantageously firstly be screwed to a corresponding interface of the positioner and, secondly, on the opposite side, again provide an interface of exactly the same type, so that a solenoid valve can be mounted on the interface. Thus, a “sandwich” configuration of the assembly, in which the adapter is located between the positioner and the solenoid valve, which each have interfaces according to the guideline VDI/VDE 3847, is advantageously obtained.
[0015] By means of a specific configuration of slots to receive fixing screws, with a comparatively low overall height of the adapter, good accessibility of the fixing screws for a tool can advantageously be obtained.
[0016] Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] By using the drawings, in which an exemplary embodiment of the invention is shown, the invention and refinements and advantages will be explained in more detail below, wherein:
[0018] FIG. 1 shows a perspective view of a connecting block;
[0019] FIG. 2 shows a connecting block with attached adapter in accordance with the invention;
[0020] FIG. 3 shows a perspective view of the rear side of the adapter in accordance with the invention;
[0021] FIG. 4 shows a plan view of the front side of the adapter in accordance with the invention; and
[0022] FIG. 5 shows a sectional view of an adapter in accordance with the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] In the drawings, the same parts are provided with the same designations.
[0024] As known, a solenoid valve having a first interface, (not shown) can be mounted on a second interface 1 of a positioner. In the exemplary embodiment shown in FIG. 1 , this second interface 1 is arranged on the rear side of a separate connecting block 2 , on the front side 3 of which, facing away, there is a further interface for a position controller (not shown). The design of the second interface 1 is familiar to those skilled in the art in the area of process instrumentation which deals with control valves and position controllers, and does not have to be explained in more detail here. In FIG. 1 , a dowel pin 4 , two threaded holes 5 and 6 and four air ducts 7 , 8 , 9 and 10 of the interface 1 are visible.
[0025] A solenoid valve mounted on the second interface 1 can be used, for example, to vent a drive, so that a positioner provided therewith moves to a safety position irrespective of the respective operating state of a position controller. If no such solenoid valve is needed, a closure cover, in which the supply of the position controller with feed air is ensured, at least via suitable internal duct guidance, can be placed on the second interface 1 .
[0026] In order that a solenoid valve can be mounted in any rotational orientation on the connecting block 2 , and thus possible collisions with further parts of the positioner can be avoided, according to FIG. 2 an adapter 11 is attached to the second interface 1 of the connecting block 2 . On its remote side, the adapter 11 has a third interface, which corresponds to the second interface 1 ( FIG. 1 ). On the visible side thereof, the adapter 11 offers a fourth interface 12 , the connecting elements 4 ′ . . . 10 ′ of which correspond to the connecting elements 4 . . . 10 of the second interface 1 . In the illustration according to FIG. 2 , the fourth interface 12 has been rotated through 180° with respect to the second interface 1 shown in FIG. 1 . Fixing screws, of which only one fixing screw 15 is visible in FIG. 2 , are screwed into threaded holes 13 and 14 in order to fix the rotational position.
[0027] FIG. 3 shows a perspective view of the adapter 11 , in which the third interface 16 thereof, which is used to mount the adapter 11 on the second interface 1 ( FIG. 1 ) of the connecting block 2 , is easily visible. During the mounting, firstly two fixing screws 17 and 18 are screwed partly into the threaded holes 5 and 6 ( FIG. 1 ) of the second interface 1 . The adapter 11 comprises a first adapter part 19 and a second adapter part 20 that can be rotated relative thereto. The second adapter part 20 is provided with a first slot 21 and a second slot 22 , which are used to receive the fixing screws 17 and 18 . During the mounting, the second adapter part 20 is firstly pushed onto the partly screwed-in fixing screw 17 in a translational movement such that the shank thereof comes to lie in the first slot 21 . The second adapter part 20 is then rotated about the axis of the fixing screw 17 until the shank of the fixing screw 18 is located in the slot 22 . This is made possible via specific cam milling of the slot 22 . The two fixing screws 17 and 18 are then tightened with an open-end wrench. By means of the described specific configuration of the second adapter part 20 , trouble-free mounting of the adapter 11 on the positioner is thus made possible, although the fixing screws 17 and 18 are not accessible from above.
[0028] The third interface 16 is configured in a way corresponding to the second interface 1 ( FIG. 1 ) and, accordingly, has a hole 4 ″ for the dowel pin 4 and ducts 7 ″, 8 ″, 9 ″ and 10 ″ which, during the connection of the third interface 16 to the second interface 1 , are connected to ducts 7 , 8 , 9 and 10 . Two fixing screws 15 and 23 are used to fix the rotational position at the two adapter parts 19 and 20 and, for the variable adjustment of the rotational position, are introduced into guide slots 24 and 25 in the shape of circular arcs.
[0029] In order to illustrate the internal structure of the adapter 11 , in FIG. 5 a sectional view for a section along a line V-V shown in FIG. 4 is illustrated. The ducts are led via the adapter 11 with the aid of concentrically arranged annular ducts 26 , 27 , 28 and 29 , which are delimited by the two adapter parts 19 and 20 and are sealed off by O-ring seals, such as a seal 30 . In FIG. 5 , by way of example, the course of duct 9 ′ of the fourth interface 12 , which can also be designated a feed duct, via the annular duct 27 and the duct 9 ″ which, in this connection, can likewise be designated a feed duct, to the third interface 16 is shown. By means of further holes, not visible in FIG. 5 , the further three passages of the air ducts are also produced in an analogous way via the annular ducts 26 , 28 and 29 . As a result of the use of the annular ducts 26 . . . 29 , the ability to rotate the two adapter parts 19 and 20 with a simultaneously stable structure for a high vibration and shock load-bearing ability is achieved.
[0030] Thus, while there have been shown, described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.
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An adapter for an assembly having a valve and a positioner, which are configured for pipeless valve mounting according to the guideline VDI/VDE 3847, wherein the adapter is intended to be installed between the valve and the positioner, and the adapter enables a variably adjustable position of the valve relative to the positioner, such that possible collisions between the valve and other parts located near the interface intended for the installation of the valve can be largely avoided.
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TECHNICAL FIELD
[0001] This document relates to processing large amounts of data.
BACKGROUND
[0002] Organizations can use enterprise resource planning (ERP) systems to manage financial data. The ERP system can periodically save the financial data to a file to record the financial status of the organization for a particular period. The file can periodically be retrieved and processed by an application program executed from application server memory, for example, to change a formatting of the file or provide some information from the file to a different organization. The processing by the application program can include storing information from the file in the application server memory and manipulating portions of the information while the information is stored in application server memory.
SUMMARY
[0003] The invention relates to processing substantial amounts of data using a database.
[0004] In a first aspect, a computer-implemented method for handling large amounts of data is to be initiated. The method includes receiving, using an application program executed from local memory of a computer system, portions of information from a first file. The method includes generating a database table in a peripheral storage device. The method includes storing the portions of information in the database table of the peripheral storage device in lieu of storing the information in the local memory of the computer system, wherein the database table and local memory are both accessible to the application program. The method includes locking the database table, wherein the locking exclusively provides the application program a database accessing technique to the database table. The method includes processing by the application program the portions of information in the database table using the database accessing technique. The method includes clearing the database table upon a termination of the application program. The method includes, unlocking the database table upon the termination of the application program.
[0005] Implementations can include any or all of the following features. The processing can include generating a second file that includes portions of the processed information. The received portions of the first file can exceed an addressable memory space of the local memory. The method can further include determining that the portions of information from the first file exceed an addressable memory space of the local memory and, in response, receiving the portions of information, generating the database table, and storing the portions of information. The database accessing technique exclusively provided to the application program can include write access to the database table. The method can further include deleting the database table upon termination of the application program. The local memory can be volatile memory that loses a capability to store information upon a power disruption and the peripheral storage device can be non-volatile memory that stores information magnetically and maintains a capability to store information upon a power disruption.
[0006] In a second aspect, a computer program product is tangibly embodied in a computer-readable storage medium and includes instructions that when executed by a processor perform a method for handling large amounts of data. The method includes receiving, using an application program executed from local memory of a computer system, portions of information from a first file. The method includes generating a database table in a peripheral storage device. The method includes storing the portions of information in the database table of the peripheral storage device in lieu of storing the information in the local memory of the computer system, wherein the database table and local memory are both accessible to the application program. The method includes locking the database table, wherein the locking exclusively provides the application program a database accessing technique to the database table. The method includes processing by the application program the portions of information in the database table using the database accessing technique. The method includes clearing the database table upon a termination of the application program. The method includes, unlocking the database table upon the termination of the application program.
[0007] Implementations can include any or all of the following features. The processing can include generating a second file that includes portions of the processed information. The received portions of the first file can exceed an addressable memory space of the local memory. The method can further include determining that the portions of information from the first file exceed an addressable memory space of the local memory and, in response, receiving the portions of information, generating the database table, and storing the portions of information. The database accessing technique exclusively provided to the application program can include write access to the database table. The method can further include deleting the database table upon termination of the application program. The local memory can be volatile memory that loses a capability to store information upon a power disruption and the peripheral storage device can be non-volatile memory that stores information magnetically and maintains a capability to store information upon a power disruption.
[0008] In a third aspect, a system for handling large amounts of data includes a processor. The system includes local memory coupled to the processor through a memory bus. The system includes a peripheral storage device. The system includes computer-readable storage medium including instructions that when executed by the processor perform a method for handling large amounts of data. The method includes receiving, using an application program executed from the local memory of a computer system, portions of information from a first file. The method includes generating a database table in the peripheral storage device. The method includes storing the portions of information in the database table of the peripheral storage device in lieu of storing the information in the local memory of the computer system, wherein the database table and local memory are both accessible to an application program. The method includes locking the database table, wherein the locking exclusively provides the application program a database accessing technique to the database table. The method includes processing by the application program the portions of information in the database using the database accessing technique. The method includes clearing the database table upon a termination of the application program. The method includes unlocking the database table upon the termination of the application program.
[0009] The described subject matter may provide for one or more benefits, such as processing the contents of a large file more quickly with a database storing portions of the file in peripheral memory than if the portions of the file were stored in application server memory. Loading the file contents into a database enables the use of database accessing techniques as opposed to memory accessing techniques. Peripheral memory is less expensive than application server memory and can store the entire contents of a file that is larger than the application server memory or an addressable address space of an operating system.
[0010] The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims.
DESCRIPTION OF DRAWINGS
[0011] FIG. 1 is a block diagram schematically representing a system for processing large amounts of data.
[0012] FIG. 2 is a flow chart of an example process for processing large amounts of data.
[0013] FIG. 3 is a block diagram schematically representing a system for processing large amounts of data.
[0014] FIG. 4 is a block diagram of a computing system that can be used in connection with computer-implemented methods described in this document.
[0015] Like reference symbols in the various drawings indicate like elements.
DETAILED DESCRIPTION
[0016] FIG. 1 is a block diagram schematically representing a system 100 for processing large amounts of data. Organizations use enterprise resource planning (ERP) systems 102 to manage and coordinate all the resources, information, and functions of the organizations' business. Part of this management includes the processing and storage of significant amounts of financial data. On occasion, a “snapshot” of an organization's current financial status can be taken and recorded before the data in an ERP system 102 changes. For example, a data extract file generator 104 can traverse data structures maintained by the ERP system, pull financial data that is relevant to a current time period, and generate a data extract file 106 to record the financial status of the organization at a specific time. The ability to take this snapshot aids organizations in meeting legal data retention and reporting requirements. For example, the data extract file 106 can be created at the end of every financial quarter. This data extract file 106 can range be rather large, on the order of several gigabytes or even terabytes in size.
[0017] The data extract file 106 can contain data from several different applications in the ERP system 102 . In some implementations, the information in the data extract file 106 is organized into segments that each store a particular type of information from documents stored by the ERP system. For example, one segment may include “Purchase order document header data” and another segment may include “Purchase order line item data,” and one segment may include “Purchase order customer data.” Thus, information from a single financial accounting document stored by the ERP system 102 (e.g., an SAP FI document) can be split into several segments, each segment including information for a portion of the document. A segment can include the same type of information from several different documents.
[0018] An organization may need to occasionally access the financial information stored in the data extract file 106 . A common example is when the organization is being audited. If the auditor is an external agency, the organization may only want to disclose the portions of the financial data that are relevant to the investigation. Further, the external agency may use software systems that can not manipulate the format of the data extract file 106 . Even if the audit is performed internally, the data extract file 106 can be large and unwieldy. A processed file 118 that includes a subset or processed version of the information in the data extract file 106 can be generated from the data extract file 106 by a data processing application 108 .
[0019] The data processing application 108 can be created with an application generator 114 specifically for processing the data extract file 106 and generating the processed file 118 . In this illustration, the data processing application is an executable file that operates autonomously to parse information from the data extract file 106 and generate the processed file 118 (a process discussed later in this document).
[0020] The application generator 114 can access a data dictionary 120 that is associated with the data extract file 106 (e.g., the data dictionary can be included in the data extract file 106 ). Every segment in the data extract file 106 can be based on a structure recorded in the data dictionary 114 . Segments in the data extract file 106 and segment definitions in the data dictionary 114 can have the same name. The data dictionary 114 can list each segment in the data extract file, fields of each segment, and provide indexes to the fields. In some examples the data dictionary identifies field descriptions, field lengths, and line or field delimiters if the fields are not a pre-determined length. That is, the data dictionary can identify metadata for the information stored in the data extract file 106 .
[0021] Application generator 114 can include a graphical user interface (GUI) that can receive user-defined configuration information 112 . The user-defined configuration information indicates a configuration of the data processing application that the application generator 114 is to generate. The data processing application generates processed file 118 in accordance to its own configuration. The user-defined configuration information 112 can identify a specific data extract file 106 from a collection of files. In some examples, the application generator 114 accesses the data dictionary 120 and presents with the GUI a list of the segments and fields in the data extract file 106 . A user of the application generator 114 can select a subset of the segments and fields to include in the processed file 118 , as well as an ordering of the segments and fields. The data processing application generated in accordance with these user selections will generate a processed file that includes the selected segments and fields.
[0022] In some implementations, the user-defined configuration information 112 includes selection criteria for fields. The selection criteria defines conditional operations to perform on data in a field of the data extract file. If a condition is not met, the data processing operation will not include the field (or a segment) in the processed file 118 . As an illustration, a field may only be copied from data extract file 106 to processed file 118 if a value contained in the field is between $1000 and $10,000. In some examples, the selection criteria can filter information from a specific year, period, company code, or depreciation area from a set of financial accounting documents. A user may request that processed file 118 only include information from financial accounting documents and not from controlling documents (e.g., SAP CO documents), source documents from material management (e.g., SAP MM documents), sales and distribution documents (e.g., SAP SD components), or asset accounting documents (e.g., SAP FI-AA documents).
[0023] In some implementations, a user of the application generator 114 selects one or more customizing tables 110 . The customizing tables provide a template for the generation of data processing application 108 . The templates can define default values that may be changed with user-defined configuration information 112 . For example, a template entitled “Separate data extract file into financial accounting documents” can define a configuration for parsing the portions of financial accounting documents from several segments and re-combining the portions into whole financial documents. The re-combined documents can be saved as one or more processed files 118 . In some examples, a user can save a user-defined configuration as a customizing table 110 .
[0024] The user-defined configuration information 112 can identify operations for the data processing application 108 to perform upon the data from extract file 106 . For example, the user can request that the data processing application 108 perform a Join operation on two or more data records from different segments to combine the data records. A user may want to specify that data for each financial accounting document should be grouped together in the processed file 118 instead of separated into segments (as noted above, each financial accounting document is parsed into segments that include a particular type of information common to several documents). In this example, the user would request that the data processing application 108 Join data from the “header data” segment and data from the “line item” segment. Additional operations that the data processing application 108 can perform upon the information parsed from the data extract file 106 are discussed later in this document.
[0025] In some implementations, a user can request that the data processing application 108 combine data from two or more separate data extracts 106 . This feature can permit the merging of data from four data extract files 106 , that each represent a fiscal quarter, into a processed file 118 that represents financial data for the entire fiscal year. In some examples, the data processing application generates several processed files 118 . For example, each of several processed files can be a financial accounting document or include financial information for a fiscal quarter (when the data extract file 106 included financial information for an entire fiscal year).
[0026] Using the received user input, the customizing tables 110 , and the data dictionary 120 , application generator 114 generates the data processing application 108 . The data processing application 108 can be executed and process information from the data extract file 106 to generate the processed file 118 . This process is detailed with reference to process 200 .
[0027] FIG. 2 is a flow chart of an example process 200 for processing large amounts of data. Process 200 will be described with reference to FIG. 3 , a block diagram schematically representing a system 300 for processing large amounts of data, as an example. In step 202 , the data processing application 108 receives portions of information from a data extract file 106 that is stored in a peripheral memory storage device 322 . For example, when the data processing application 108 is executed, it performs a process that sequentially reads the portions of information from the peripheral memory storage 322 into primary storage 302 (e.g., a cache of the CPU 306 or the application server memory 304 ). The application server memory 304 can include a buffer for temporarily storing portions of the data extract file 106 before the portions are stored in a database, as described later in this document.
[0028] In step 204 , the data processing application 108 generates at least one database table 116 in the peripheral memory storage device 322 to store the received portions of information from data extract file 106 . In some examples, the data processing application generates a database table 116 for each segment in the data extract file 106 . Each table can include a column for each field in a segment. The data processing application may include information identifying the segments and fields in the data extract file 106 or can identify the segments and fields from the data dictionary 120 during runtime. In some implementations, the data processing application 108 requests that a database management system (DBMS) 308 create the database table (and subsequently organize, store, manage, and retrieve records in the database).
[0029] In step 206 , the data processing application locks the database table 116 . A lock provides a single application program exclusive access to the records in the database table 116 . In some examples, the application program provided exclusive access is the only application program that can write to the locked database table 116 . In various examples, the application program provided exclusive access is the only application program that can read from the locked database table 116 . In some examples, the application program provided exclusive access is the only application program that can perform database accessing techniques (e.g., join, merge, sort, summarization). Other application programs may be unable to read or write to the locked database table. In examples where the locking and access to the database tables is controlled by the DBMS, the DBMS will not provide other application programs using the DBMS access to locked tables.
[0030] In step 208 , the data processing application 114 stores a received portion of information into an appropriate database record. To store the information in an appropriate record, the data processing application 108 uses information from the data dictionary 120 to identify a semantic meaning of a portion of information received into primary memory storage 302 (e.g., a buffer in application server memory 304 ). For example, the application program 108 can identify the first 25 characters in the buffer as being associated with a “name” field for a “header data” segment that originated from a “Fiscal Year 2008” financial accounting document. The data processing application 114 can store the 25 character portion of information in the “name” column for a “header data” database table.
[0031] After storing of the portion of data in the database table 116 , the portion of data can be removed from the primary memory storage 202 or replaced in the primary memory storage 202 with a new portion of data from the data extract file 106 . The receipt of information, identification of a portion of the information, and copying of the portion of information to a database table can be repeated for an entire sequential sequence of data read from data extract file 106 . The primary memory storage 302 available to the data processing application 114 for withdrawing portions of data from the file 106 and placing the portions in the database tables 116 can be much smaller than a size of the data extract file 106 and a size of the database tables 116 .
[0032] In step 210 , the data processing application 114 generates an index to the one or more database table. The database index is a data structure that improves the speed of operations (e.g., retrieval or processing) on records stored in the database table. A database index provides the data processing application efficient access to the ordered portions of information stored in the database tables 116 . In some implementations, this step is optional. In other implementations, several indexes are generated for the one or more database tables.
[0033] In step 212 , the data processing application 108 processes the information in the database. For example, a user of the application generator 114 may have requested that the processed file 118 only include information from three financial accounting documents (while the data extract file includes information from several types of hundreds of documents). Because information from a financial accounting document is separated into different tables (e.g., one table may include “Purchase Order document header data” and another table may include “Purchase order line item data”), the information corresponding to a single financial accounting document needs to be collected from the different tables. In this illustration, a “Join” operation can be performed to combine data records from two or more tables (each representing a segment) in the database (representing all the data from the data extract file). The Join operation can copy one record to another, place the Joined records in a new table, or copy the joined records to application server memory 304 .
[0034] A Join request can conditionally operate, in some examples. For instance, the data processing application 108 may only Join two records if the records are from the same financial accounting document. The origin of the records can be verified by checking if the document number, company code, and posting period for a group of fields for the “header data” segment is the same as for the “line item data” segment. In some implementations, the Join statements compare records that contain similar data, even if the records do not share a common name. The data processing application 108 can perform other database operations upon data records in the locked tables of database 116 . For example, the data processing application 108 can perform merge, sort, and summarization operations. A merge statement can insert new records or update existing records, depending on whether or not a condition is satisfied.
[0035] As an illustration, a user of the application generator can request that that data processing application program generate processed file that includes a list of FI documents ordered by document number and fiscal year for a certain range of customers. The data processing application program generates three database tables from the segments in the data extract file: one for FI document header data, one for FI document item data, and one for customer data. The user of the application generator has additionally requested that the data extract file include a subset of the information from the document items table (e.g., only amounts and customer numbers) and a subset of information from the customer table (e.g., only customer names and addresses). The data processing application performs a Join on the three database tables with the condition “header-doc.no.=item-doc.no.” and “item-cust.no.=cust-cust.no.” In addition, the data processing application performs a grouping right during the database selection and a summarization of the amounts for each customer number. These operations directly provide a result for output to the processed file.
[0036] If the data was stored within tables in application server memory instead of the database, similar operations would be time consuming and require additional memory. For example, processing three separate internal tables would require a nested loop about the three tables (i.e., a loop at the customer data within a loop at the item data within a loop at the header data) and a comparison of the fields. The data processing application program would additionally need to manually sort and summarize the data without being able to rely upon the corresponding database operations. Further, the use of nested loops requires additional time and processing resources. Additional application server memory is required to copy the data into a result table to perform the sorting.
[0037] In some implementations, the data processing application 114 generates the processed file 118 from information in the database tables 116 after the processing of the information in the database tables (e.g., after step 212 ). For example, the data processing application can perform queries (e.g., Join or Sort queries) of tables in the database and copy the responsive information to the processed file 118 . The processed file 118 can grow in size following each database operation requested by the data processing application 114 .
[0038] In step 214 , the application program clears the one or more database tables 116 by deleting all the records in the table or writing over the records in the table. The application program then unlocks the database table (step 216 ) to free the table for use by other processes. In some examples, the database table is deleted, either after the clearing or unlocking, or in lieu of the unlocking and/or cleaning.
[0039] Process 200 can provide an efficient method for handling large amounts of data from the data extract file 106 . Less efficient methods include reading the information from the data extract file 106 into internal tables in application server memory 304 (e.g., internal tables defined by the data processing application 108 using the Advanced Business Application Programming language). Access to the internal tables is quick, but the internal tables do not provide data processing application 108 the breadth of operations that are provided by a database system. In other words, the memory accessing techniques are not as robust as the database accessing techniques.
[0040] When application server memory is used to store file contents for processing, the data processing application is limited in the size of the data extract file 106 that it can operate upon. As an illustration, the data extract file 106 may be five gigabytes and the application server memory 304 only one gigabyte. The inability to store the entire file in the application server memory 304 leads to either memory overflow, the use of virtual memory, or inefficient recursive calls for portions of the data extract file 106 from the peripheral memory storage 322 . During the recursive calls, data portions are processed, and upon requiring data that is not in application server memory 304 , additional portions of the data extract file 106 needs to be brought into application server memory 304 and overwrite existing data. Because the data extract file 106 is not structured like the database or internal tables, accessing information from the file is inefficient.
[0041] In another illustration, an ability to add additional application server memory 304 is limited. For example, a 32-bit operating system only permits addressing four gigabytes of data. Virtual memory does not provide an adequate solution because it can be very slow (requiring the loading of page tables similar to the recursive calls previously described) and is constrained by the addressable memory space of an operating system. If a data extract file is 217 gigabytes, virtual memory on a 32-bit system is not capable of providing access to contents of the entire file, and recursive calls to the data extract file is too inefficient.
[0042] The system described in the present disclosure does not have the same size constraints as the application server memory or the use of virtual memory. In addition, the system described in the present disclosure can provide access to information more quickly than virtual memory. With a 64-bit operating system, the addressable memory space for the application server memory is larger than a 32-bit system, but the cost of sufficient application server memory to handle large data extract files 106 can be prohibitively expensive.
[0043] The system described in the present disclosure enables a data processing application to realize the various benefits of processing data using database accessing techniques instead of application server memory accessing techniques. The database tables are generated by the data processing application subsequent to the execution of the data processing application and are removed prior to the termination of the application program. The database tables, in this respect, are similar to the use of tables in application server memory. The use of a database, however, enables the efficient processing storing of significantly more data and the use of more robust accessing techniques.
[0044] In some implementations, the application generator 114 identifies a size of the data extract file 106 or portions of the data extract file that are selected for processing. If the application generator 114 determines that the size of the data extract file or the portions thereof exceed a size of application server memory 304 , a data processing application 108 can be generated that copies the portions of information from the data extract file 106 into the database table 116 , as described above. If the application generator 114 determines that the size does not exceed the size of the application server memory 304 , a data processing application 108 can be generated that reads the portions of information from the data extract file 106 into local tables in application program memory.
[0045] Processing data in the application program memory local tables can be faster than processing the data in database tables. This determination by the application generator can generate a data processing application 108 that processes the data extract file 106 in the most efficient method. In some examples, the data processing application determines that the size of the file or the portions thereof exceeds a size of application server memory that is allocated for use by the data processing application, or addressable memory space available to the data processing application 108 .
[0046] In some implementations, an interface receives instructions from the data processing application 108 that are intended for processing data in application server memory local tables. The interface can modify the instructions and transmit them to database tables. For example, the data processing application 108 can read a portion of information from the data extract file 106 and transmits to the interface a request that the portion of information be stored within local tables stored in application server memory. The interface can modify the request and transmit the request to a DBMS. The interface can similarly intercept instructions to process data in application server memory local tables. The use of an interface enables the features discussed in this document to be implemented on an application program without modification of the application program source code.
[0047] In some implementations, a separate application program receives the portions of information from the data extract file 106 and stores the portions of information in the database table generated by either the data processing application 108 or the DBMS. This separate application program can be generated by application generator 114 and can signal the data processing application upon copying all the information from the data extract file 106 to the database tables 116 . Information from the data extract file may never pass through the portion of application server memory 304 allocated to the data processing application 108 .
[0048] In some implementations, the data processing application and the application generator 114 are portions of the same application program. The data processing application 108 can represent a portion of the application program that reads the data extract file 106 and processes information from the data extract file, while the application generator 114 can represent a portion of the application program that interfaces with a user to identify the operations that should be performed by the data processing application 108 . The data processing application program need not be a separate executable file.
[0049] In some implementations, the data extract file 106 is a flat file. The data extract file can contain data that does not have any structured relationships. For example, the file can be a comma-delimited ASCII file. The data extract file 106 can be a comma-separated value (CSV) file. Fields coped to the data extract file 106 may not include links to other fields copied to the data extract file 106 . The structure of the data extract file 106 may only be addressable from data processing applications 108 .
[0050] In some implementations, the primary memory storage includes a CPU 306 cache and application server memory 304 . The application server memory 304 can be RAM or other electronic memory storage that the CPU can access via system bus 310 and execute instructions from in synchrony with the system bus 3 10 . The application server memory 304 can store running processes. For example, application generator 108 , data processing application 114 , and DBMS 308 can run or be executed from the application server memory 304 . In some examples, the application server memory 304 is only accessible to the one CPU 306 . No other CPUs can access the application server memory 304 . The primary memory storage 302 can be volatile, electronic memory storage. For example, the CPU cache and application server memory 304 can lose stored information when power to the components is disrupted.
[0051] In some implementations, the peripheral memory storage is persistent, non-volatile memory storage 322 . If power is disrupted to the peripheral memory storage 322 , information stored by the peripheral memory storage is not lost. For example, the data extract file 106 , the processed file 118 , and the database tables 116 are capable of being stored in memory 322 without a power source. The peripheral memory storage can be magnetic storage, for example a disk drive. In various examples, information from the peripheral memory is transferred to the primary memory storage over an external data bus 318 (e.g., using IDS, SATA, ATA, or SAS interfaces). In some examples, the data extract file 106 , the processed file 118 , and the database tables 116 are stored in different peripheral memory storages 322 .
[0052] FIG. 4 is a schematic diagram of a generic computer system 400 . The system 400 can be used for the operations described in association with any of the computer-implement methods described previously, according to one implementation. The system 400 includes a processor 410 , a memory 420 , a storage device 430 , and an input/output device 440 . Each of the components 410 , 420 , 430 , and 440 are interconnected using a system bus 450 . The processor 410 is capable of processing instructions for execution within the system 400 . In one implementation, the processor 410 is a single-threaded processor. In another implementation, the processor 410 is a multi-threaded processor. The processor 410 is capable of processing instructions stored in the memory 420 or on the storage device 430 to display graphical information for a user interface on the input/output device 440 .
[0053] The memory 420 stores information within the system 400 . In one implementation, the memory 420 is a computer-readable medium. In one implementation, the memory 420 is a volatile memory unit. In another implementation, the memory 420 is a non-volatile memory unit.
[0054] The storage device 430 is capable of providing mass storage for the system 400 . In one implementation, the storage device 430 is a computer-readable medium. In various different implementations, the storage device 430 may be a floppy disk device, a hard disk device, an optical disk device, or a tape device.
[0055] The input/output device 440 provides input/output operations for the system 400 . In one implementation, the input/output device 440 includes a keyboard and/or pointing device. In another implementation, the input/output device 440 includes a display unit for displaying graphical user interfaces.
[0056] The features described can be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. The apparatus can be implemented in a computer program product tangibly embodied in an information carrier, e.g., in a machine-readable storage device, for execution by a programmable processor; and method steps can be performed by a programmable processor executing a program of instructions to perform functions of the described implementations by operating on input data and generating output. The described features can be implemented advantageously in one or more computer programs that are executable on a programmable system including at least one programmable processor coupled to receive data and instructions from, and to transmit data and instructions to, a data storage system, at least one input device, and at least one output device. A computer program is a set of instructions that can be used, directly or indirectly, in a computer to perform a certain activity or bring about a certain result. A computer program can be written in any form of programming language, including compiled or interpreted languages, and it can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment.
[0057] Suitable processors for the execution of a program of instructions include, by way of example, both general and special purpose microprocessors, and the sole processor or one of multiple processors of any kind of computer. Generally, a processor will receive instructions and data from a read-only memory or a random access memory or both. The essential elements of a computer are a processor for executing instructions and one or more memories for storing instructions and data. Generally, a computer will also include, or be operatively coupled to communicate with, one or more mass storage devices for storing data files; such devices include magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; and optical disks. Storage devices suitable for tangibly embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, such as EPROM, EEPROM, and flash memory devices; magnetic disks such as internal hard disks and removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, ASICs (application-specific integrated circuits).
[0058] To provide for interaction with a user, the features can be implemented on a computer having a display device such as a CRT (cathode ray tube) or LCD (liquid crystal display) monitor for displaying information to the user and a keyboard and a pointing device such as a mouse or a trackball by which the user can provide input to the computer.
[0059] The features can be implemented in a computer system that includes a back-end component, such as a data server, or that includes a middleware component, such as an application server or an Internet server, or that includes a front-end component, such as a client computer having a graphical user interface or an Internet browser, or any combination of them. The components of the system can be connected by any form or medium of digital data communication such as a communication network. Examples of communication networks include, e.g., a LAN, a WAN, and the computers and networks forming the Internet.
[0060] The computer system can include clients and servers. A client and server are generally remote from each other and typically interact through a network, such as the described one. The relationship of client and server arises by virtue of computer programs running on the respective computers and having a client-server relationship to each other.
[0061] A number of embodiments have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of this disclosure. Accordingly, other embodiments are within the scope of the following claims.
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Among other disclosed subject matter, a computer-implemented method for handling large amounts of data is to be initiated. The method includes receiving, using an application program executed from local memory of a computer system, portions of information from a first file. The method includes generating a database table in a peripheral storage device. The method includes storing the portions of information in the database table of the peripheral storage device. The method includes locking the database table, wherein the locking exclusively provides the application program a database accessing technique to the database table. The method includes processing by the application program the portions of information in the database table using the database accessing technique. The method includes clearing the database table upon a termination of the application program. The method includes, unlocking the database table upon the termination of the application program.
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CROSS REFERENCE TO A RELATED APPLICATION
This is a continuation-in-part of my copending application Ser. No. 775,242, filed on July 15, 1985, now abandoned.
BACKGROUND OF THE INVENTION
The invention disclosed herein is useful in several processes used by the pulp and paper industry. During pulping processes, cellulosic fibers must be liberated from their encasing lignin matrix so that they can associate with one another, yielding strength in the final product. This polymer separation can be accomplished by removal of lignin as in chemical pulps, or by maintaining the lignin as in high yield mechanical pulps. During the bleaching process, lignin is removed and the resulting pulp is brightened.
The secondary cell wall of wood, composed of cellulose fibrils, hemicellulose and lignin, imparts physical strength and rigidity to woody plants. The cellulose fibrils are densely packed and surround the cell in regular parallel arrays, or in crisscross layers. These fibrils are held together by a matrix of hemicellulose and lignin.
Cellulose is the most abundant component of woody tissue, comprising 35-45% of the dry weight. Cellulose is an ordered linear polymer of glucose monomers coupled by β-1,4 bonds. The hemicelluloses are branched polymers composed of pentose (5-carbon) monomers, normally xylose and arabinose; and hexose (6-carbon) monomers, consisting of glucose, galactose, mannose and substituted uronic acid.
Lignin is an extremely complex polymer formed by the free radical polymerization of substituted cinnamyl alcohol procursors. Lignin constitutes 15-35% of dry wood weight.
Lignin is highly resistant to biological attack; not a surprising finding considering the complexity and stability of lignin structure. No organism has been demonstrated to grow on lignin as the sole carbon source. The complex lignin polymer, however, is completely degraded by pure cultures of various higher order fungi. For reviews see Higuchi (1982) Experientia 38: 159-166, and Janshekar, H. and Feichter, A. (1983) "Advances in Biochemical Engineering/Biotechnology," A. Fiechter and T. W. Jeffries, Eds., Vol. 27, pp. 119-178, Springer, Berlin; Kirk, T. K. (1984) in "Biochemistry of Microbial Degradation," D. P. Gibson, Ed., pp. 339-437, Marcel Dekker, N.Y. The major degraders of "fully lignified" tissues (lignin >20%) are the basidiomycetes that cause the white-rot type of wood decay. The most extensive physiological investigations of lignin biogradation by white-rot fungi have been conducted with a single member of the family Corticraceae, Phanerochaete chrysosporium Burds.
Although P. chrysosporium is capable of completely degrading lignin, purified lignin will not support its growth. Purified cellulose, however, is a growth nutrient for these fungi. Lignin degradation allows these fungi to expose the cellulose food source contained within the lignin matrix. Under defined laboratory conditions, fungal lignin degradation is not observed during the approximately first 3 days of culture. Subsequently, the culture becomes starved for carbon or nitrogen. Lignin degradation is first observed one or two days later and is maximal at 6 days. The induction of lignin degradation in response to carbon and nitrogen starvation indicates that fungal lignin metabolism is a secondary metabolic event (Keyser, P., Kirk, T. K. and Zeikus, J. G. [1978] J. Bacteriol. 135: 790-797.).
Fungal lignin degradation is commercially impractical for several reasons. The rate of lignin degradation is unacceptably slow since ligninolytic activity must be induced by starvation. Furthermore, fungi metabolize cellulose fibers are their primary food source, resulting in reduced pulp yield and an inferior pulp product.
With regard to the major C--C and C--O--C intersubunit linkages found in lignin, it is important to note that approximately 80% of intersubunit bonds involve linkages to the C.sub.α or C.sub.β carbons.
Tien and Kirk have disclosed a ligninase preparation capable of oxidatively cleaving C.sub.α -C.sub.β bonds in lignin model compounds (Tien, M. and Kirk, T. K. [1984] Proc. Natl. Acad. Sci. 81: 2280-2284). This preparation displays on an SDS-polyacrylamide gel predominantly one protein with an apparent molecular weight of 42 kilodaltons and several minor bands. Thus the preparation is a mixture of proteins without any means suggested for isolating the dominant protein from the minor bands. Subsequent to the publication of this paper, several scientific papers were published disclosing an inability to isolate the major protein from the mixture. These articles are as follows: Huynh, V-B and Crawford, R. L. (1985) FEMS Microbiology Letters 28: 119-123; Leisola, M. et al. (1985) Lignin Biodegradation Workshop; and Gold, M. H. et al. (1985) Lignin Biodegradation Workshop.
These protein isolations have been done by either ion-exchange chromatography or size exclusion-ion exchange column chromatography. The fractions containing ligninase have been analyzed by isoelectric focusing or SDS-polyacrylamide gel electrophoresis, and have shown multiple proteins. The scientists who performed this work are at the forefront of the lignin enzyme field, as evidenced by their participation in the Lignin Biodegradation Workshop held in Vancouver, BC in 1985.
With this background of prior art failures, the inventors of the subject invention were faced with a seemingly insurmountable problem. The invention disclosed herein has successfully solved the problem by producing a substantially pure preparation, designated rLDM™ 6, which is free of other proteins contained in the Tien and Kirk mixture disclosed above.
Advantageously, the preparation of the subject invention, rLDM™ 6, possesses desirable properties for use in pulping wood and treating effluent which the Tien and Kirk preparation did not have. Specifically, the Tien and Kirk mixture has a lower specific activity than the rLDM™ 6 of the subject invention.
There is a clear need to isolate and identify other enzymes which can be used to catalyze the degradation and modification of lignin. The novel rLDM™ of the subject invention are useful for this purpose.
These novel compounds are lignin-degrading enzymes which will not attack cellulose or hemicellulose. The enzymes are immediately active and require no metabolic induction; therefore they overcome the drawbacks of fungi previously mentioned for use in pulp operations.
BRIEF SUMMARY OF THE INVENTION
The subject invention concerns novel lignin-degrading enzymes which are called rLDM™ 1, rLDM™ 2, rLDM™ 3, rLDM™ 4, rLDM™ 5, and rLDM™ 6. These novel compounds, advantageously, possess the properties of (1) reducing the amount of lignin in kraft pulp, (2) enhancing the strength properties of thermomechanical pulp (TMP) and (3) decolorizing kraft lignin. The rLDM™ of the subject invention are characterized herein by the critical property of being able to catalyze the oxidation of veratryl alcohol to veratrylaldehyde, and the following physical parameters:
(1) molecular weight as determined by SDS-PAGE;
(2) amino acid composition;
(3) heme content;
(4) homology by antibody reactivity;
(5) specificity of activity against lignin model substrates; and
(6) elution from a FPLC column at specified sodium acetate molarities.
The lignin-degrading enzymes of the invention, referred to as rLDM™, are referred to as Pulpases™ in co-pending application Ser. No. 755,242.
DETAILED DESCRIPTION OF THE INVENTION
The isolation of the novel rLDM™ of the subject invention was facilitated by use of a novel stable mutant strain of Phanerochaete chrysosporium, which elaborates high amounts of ligninolytic enzymes into the fermentation medium. The novel mutant strain, designated SC26, has been deposited in the permanent collection of a public culture repository, to be maintained for at least 30 years. The culture repository is the Northern Regional Research Laboratory, U.S. Dept. of Argiculture, Peoria, Ill. 61604, USA. The accession number is NRRL 15978, and the deposit date is July 3, 1985. This deposited culture is available to the public upon the grant of a patent disclosing it. The deposit also is available as required by foreign patent laws in countries wherein counterparts of the subject application, or its progeny, are filed. However, it should be understood that the availability of a deposit does not constitute a license to practice the subject invention in derogation of patent rights granted by governmental action.
Novel mutant SC26 was obtained by UV mutagenesis of the wild type Phanerocheate chrysosporium, ATCC 24725.
Novel mutant SC26 was grown on a nitrogen-limited trace element medium supplemented with glucose and buffered at pH 4.5.
Ligninase activity in the fermentation medium was measured periodically by standard means determining the rate of oxidation of veratryl alcohol to veratrylaldehyde.
Isolation and purification of the novel rLDM™ of the subject invention from the extracellular fluid in the fermentation was accomplished by ultrafiltration and FPLC using an anion exchange column.
Following are examples which illustrate the novel enzymes and procedures, including the best mode, for practicing the invention. These examples should not be construed as limiting. All percentages are by weight and all solvent mixture proportions are by volume unless otherwise noted.
EXAMPLE 1
Growth of Mutant SC26 (NRRL 15978) to Product Fermentation Medium Containing Novel Ligninaes
Inoculum was prepared by homogenizing 50 ml of 1.5-day cultures of mutant SC26 grown in 1 liter flasks containing the following medium, designated nitrogen-limited BIII/glucose medium:
The BIII medium contains 1.08×10 -3 M ammonium tartrate, 1.47×10 -2 M KH 2 PO 4 , 2.03×10 -3 M MgSO 4 .7H 2 O, 6.8×10 -4 M CaCl 2 .2H 2 O, 2.96×10 -6 M thiamine.HCl an 10 ml.L -1 of a trace element solution. The trace element solution contains 7.8×10 -3 M nitriloacetic acid, 1.2×10 -2 M MgSO 4 .7H 2 O, 1.7×10 -2 M NaCl, 3.59×10 -4 M FeSO 4 .7H 2 O, 7.75×10 -4 M CoCl 2 , 9.0×10 -4 M CaCl 2 , 3.48×10 -4 M ZnSO 4 .7H 2 O, 4×10 -5 M CuSO 4 .5H 2 O, 2.1×10 -5 M AlK(SO 4 ) 2 .12H 2 O, 1.6×10 -4 M H 3 BO 3 , 4.1×10 -5 MNaMoO 4 .2H 2 O and 2.9×10 -3 M MnSO 4 .H 2 O.
The medium was supplemented with 10% (by wt/liter) of glucose.
The medium was buffered with 10 mM trans-aconitic acid, pH 4.5.
Flasks (125 ml, containing 10 ml sterile medium having the above-described medium) were each inoculated with 0.5 ml of the above homogenate and kept stationary at 39° C. The flasks were flushed on days 0, 3, and 6 with water-saturated O 2 . Alternatively, a rotating biological contractor (RBC) was used to grow the fungus. 2.5 liters of the above-described medium was inoculated with 100 ml of the above homogenate and grown at 39° C. with the RBC rotating at 1 rpm with continuous oxygenation.
Logninase activity was measured periodically by determining the rate of oxidation of veratryl alcohol to veratrylaldehyde. Reaction mixtures contained 275 μl of extracellular fluid (from flasks or the RBC), 2 mM veratryl alcohol, 0.4 mM H 2 O 2 and 0.1 mM sodium tartrate, pH 2.5 in a final volume of 0.5 ml. The reactions were started by H 2 O 2 addition immediately after buffer was added and were monitored at 310 nm. Protein was determined according to Bradford (Bradford, M. M. [1976] Anal. Biochem. 72: 248-254) using bovine serum albumin (Sigma Chemical, St. Louis, MO) as standard.
EXAMPLE 2
Isolation and Purification of the Novel rLDM™
The extracellular growth media from cultures grown in flasks, as described above, was harvested by centrifugation at 5000×G, 10 min, 4° C. Extracellular growth media was then concentrated by ultrafiltration through a 10K filter. The resulting concentrate is called the Ligninolytic Mixture™. The rLDM™ contained in this Ligninolytic Mixture™ were separated by fast protein liquid chromatography (FPLC) using a Pharmacia Mono Q column (Pharmacia, Piscataway, NJ) and a gradient of sodium acetate buffer, pH 6, from 10 mM to 1M. rLDM™ 1, 2, 3, 4, 5, and 6 elute from the column in a typical preparation at the following sodium acetate molarities, respectively: 0.16, 0.18, 0.34, 0.40, 0.58, and 0.43M to give essentially opure rLDM™ 1-6. Each rLDM™ is substantially free of other rLDM™ and native proteins.
Characterization of the Novel rLDM™
The rLDM™ have been characterized by the following criteria:
(1) ability to catalyze the oxidation of veratryl alcohol to veratrylaldehyde;
(2) molecular weight as determined by SDS-PAGE;
(3) amino acid composition;
(4) heme content;
(5) homology by antibody reactivity;
(6) specificity of activity against lignin model substrates; and
(7) elution from an FPLC column at specified sodium acetate molarities.
All of the rLDM™ catalyze the oxidation of veratryl alcohol to veratryladehyde, as monitored spectrophotometrically at 310 nm. A unit of activity is defined as the production of 1 micromole of veratrylaldehyde in the rLDM™ catalyzed reactions. The specific activities of typical preparations at about 24° C. are as follows:
______________________________________rLDM ™ 1 2 3 4 5 6______________________________________SPECIFIC ACTIVITY 2.6 17.1 5.1 9.7 9.4 12.4UNITS/MG · MINUTEMOLECULAR 38 38 42 42 43 42WEIGHT kD______________________________________
Amino acid composition--See Table 1.
Heme and carbohydrate content--rLDM™ 1, 2, 3, 4, 5, and 6 each contain a single protoheme IX moiety. All are glycosylated according to periodic acid staining (PAS) and binding to Con A-Sepharose (Sigma).
TABLE I__________________________________________________________________________Amino Acid Composition of rLDM ™ rLDM ™1 rLDM ™ 2 rLDM ™ 3 rLDM ™ 5 rLDM ™ 6Amino Acid Ratio Ratio Ratio Ratio Ratio__________________________________________________________________________asp/asn 1.4 2.0 5.4 5.0 3.0glu/gln 6.0 7.7 16.8 19.9 8.0ser 4.3 4.1 14.0 22.3 6.8his 4.4 3.2 7.3 15.9 3.2gly 6.5 5.7 24.0 44.7 8.3thr 2.2 3.5 -- -- 4.9arg 1.1 1.2 2.9 4.8 1.3ala 7.3 7.9 14.4 13.8 6.7tyr 0.2 -- 1.0 1.0 0.2met -- -- 1.2 -- 0.14val 1.6 2.6 7.4 6.5 4.2phe 1.1 3.0 7.0 3.3 3.2ile 1.0 2.2 4.1 3.6 2.4leu 1.5 2.6 6.5 6.0 3.3lys 0.5 1.0 2.5 2.3 1.0__________________________________________________________________________
Immunoblot Procedure
This procedure was used to further characterize the rLDM™. It is a standard procedure which is disclosed in Towbin et al. (Towbin, H., Staehelin, T. and Gordon, J. [1979] Proc. Natl. Acad. Sci. USA 76: 4350). The procedure involves separating the proteins by electrophoresis in a gel, transfer of the proteins to a solid matrix, and reacting with (1) a primary probe, rabbit anti-rLDM™ antibody and (2) a secondary probe, goat anti-rabbit antibody coupled to horseradish peroxidase.
rLDM™ 1, 3, 4, 5, and 6 react to polyclonal antibodies made to rLDM™ 2 and 6, using the above immunoblot procedures. rLDM™ 2, in the same procedure, reacts to polyclonal antibodies made to rLDM™ 6.
All the rLDM™ disclosed herein have the following unique activities on lignin model substrates:
(1) oxidative cleavage of C.sub.α -C 62 ;
(2) hydroxylation of benzylic methylene groups;
(3) oxidation of benzyl alcohols to aldehydes;
(4) phenol oxidation; and
(5) oxidative cleavage of methoxyl groups.
"Lignin model substrates" are chemicals which resemble parts of lignin. The above activities are characteristic of the rLDM™ disclosed herein.
EXAMPLE 3
Bleaching of Kraft Pulp with rLDM™
rLDM™ 1-6, alone, or mixtures thereof, are added to kraft pulp having a characteristic brown color at 3% consistency in 10 mM trans-aconitic acid, pH 4.5, 400 μM H 2 O 2 and 100 μM MnSO 4 . The pulp slurry is flushed with O 2 and incubated with slow shaking at 39° C. for 12 hr, after which the kraft pulp solution is decanted, and a 1M NaOH solution is added to the pulp and incubated for 60 min at 65° C. This is then decanted and the kraft pulp is washed in water. The resulting kraft pulp no longer has a dark brown color, but instead has a desired lighter color.
The use of MnSO 4 is optional.
EXAMPLE 4
Treatment of Thermomechanical Pulp (TMP) with rLDM™
rLDM™ 1-6, alone, or mixtures thereof, are added to 10 gm of TMP (dry weight) at 3% consistency in 10 mM trans-aconitic acid, pH 4.5, 400 μM H 2 O 2 and 100 μM MnSO 4 . The pulp slurry is flushed with O 2 and incubated with slow shaking at 39° C. for 12 hr, after which time the TMP is washed with water. The tensile, tear and burst indices as well as breaking length of the pulp are measured and found to be of enhanced strength versus an untreated sample. The brightness reversion of the treated sample is less than the untreated sample; therefore, brightness stability is increased with the rLDM™ treatment.
The use of MnSO 4 is optional.
The rLDM™ of the subject invention can be used in the crude form, in a purified form, wherein each rLDM™ is substantially free of other rLDM™ and native proteins, and in mixtures thereof. It is well within the skill of a person skilled in the art to adjust amounts of rLDM™ used in accordance with the purity of the rLDM™ preparation.
"Native proteins" as used herein refers to other proteins present in the extracellular fermentation medium, as described above.
EXAMPLE 5
Treatment of Wood Pulp with rLDM™
One part of wood pulp is treated with about 10×10 -6 to about 20×10 -6 parts of a rLDM™ in about 40 mM trans-aconitic acid, pH 4.5, at about 39° C. for about 1 to about 16 hr. The pulp is then washed in about 1M NaOH at about 65° C. for about 1 hr, and rinsed in water. This treatment of the wood pulp results in the removal of about 1/3 of the lignin as evidenced by the reduction of kappa number from about 18 to about 13.
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Novel lignin-degrading enzymes designated rLDM™1, rLDM™2, rLDM™3, rLDM™4, rLDM™5, and rLDM™6 are isolated and purified to the essentially pure form, wherein each rLDM™ is substantially free of other rLDM™ and native proteins, from the extracellular medium of a novel mutant microbe. The novel mutant, designated SC26, produces large amounts of the rLDM™, thus facilitating the isolation and purification of them. These rLDM™ are useful in pulping processes to degrade and/or modify lignin.
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BACKGROUND
[0001] 1. Field of the Invention
[0002] The present invention relates to power amplifiers, particularly switched-mode power amplifiers.
[0003] 2. Description of Related Art
[0004] Switched-mode power amplifiers have demonstrated the capability of producing, with high power-added efficiency (PAE), phase-modulated signals that have very high signal quality—i.e., low root-mean-square (RMS) phase error relative to an ideal signal and little or no degradation in power spectral density (PSD). These power amplifiers have also been demonstrated to be highly tolerant of temperature variation, and are believed to be highly tolerant to fabrication-process variation, making them attractive for high-volume applications such as consumer electronics. Such power amplifiers include a switch connected to a resonant network; the output of the resonant network is connected in turn to a load (e.g., the antenna in a radio transmitter).
[0005] An early switched-mode amplifier is described in U.S. Pat. No. 3,900,823 to Sokal et al., incorporated herein by reference. Sokal et al. describes the problem (created by unavoidable feedthrough from amplifier input to amplifier output) of power control at low power levels and proposes solving the problem by controlling RF input drive magnitude to a final amplifier stage. In particular, the input drive magnitude of the final stage is controlled by using negative feedback techniques to control the DC power supply of one or more stages preceding the final stage. Various other known techniques use variation of amplifier power supply for linearization as described, for example, in the following patents, incorporated herein by reference: U.S. Pat. No. 5,091,919; U.S. Pat. No. 5,142,240, and U.S. Pat. No. 5,745,526.
[0006] Another type of switched-mode amplifier, that does not require the use of negative eedback as in Sokal, is described in U.S. patent application Ser. Nos. 09/247,095 and 09/247,097 of the present assignee, entitled HIGH-EFFICIENCY MODULATING RF AMPLIFIER and HIGH-EFFICIENCY AMPLIFIER OUTPUT LEVEL AND BURST CONTROL, respectively, filed Feb. 9, 1999 (W00048306 and W00048307) and U.S. patent application Ser. No. ______(Dkt. 090729HEM2. US), entitled FHGH-EFFICIENCY MODULATING RF AMPLIFIER, filed Aug. 10, 2000, all incorporated herein by reference. In the latter switched-mode power amplifiers, the average power is determined by two signals: the switch supply signal and the switch control signal. The switch supply signal is the DC voltage available on one side of the switch; as this voltage increases, the peak voltage of the oscillatory signals developed within the resonant network and subsequently delivered to the load also increases. The switch control signal is typically a phase-modulated signal that controls the switch (i.e., determines whether the switch is on or off). This switch control signal should be strong enough to toggle the switch on and off but should not be excessively strong: unlike a linear amplifier in which the strength of the output signal is determined by the strength of the input signal, in a switched-mode power amplifier, if the switch control signal is too strong, the excess signal merely leaks through the switch and into the resonant network (i.e., feedthrough). When this occurs, a version of the switch control signal that is out-of-phase with respect to the desired signal adds to the desired signal within the resonant network, altering both the phase and the amplitude of the output signal in an undesirable way.
[0007] French Patent 2,768,574 also describes a switched-mode power amplifier arrangement. Referring to FIG. 1 , in this arrangement, the power amplifier circuit comprises a DC-to-DC converter 20 and a power amplifier 30 . The DC-to-DC converter 20 includes a pulse-width modulator 22 , a commutator/rectifier 24 and a filter 26 .
[0008] The pulse-width modulator 22 is coupled.to receive a DC-to-DC command input signal from a signal input terminal 21 , and is arranged to apply a pulse-width-modulated signal to the commutator/rectifier 24 . The commutator/rectifier 24 is coupled to receive a DC-to-DC power supply input signal from a signal input terminal 25 , and is also coupled to apply a switched signal to filter 26 . The filter 26 in turn applies a filtered switched signal 28 in common to multiple stages of the power amplifier 30 .
[0009] A circuit of the foregoing type is substantially limited by the frequency of the pulse-width modulator. In addition, common control of multiple power amplifier stages in the manner described may prove disadvantageous as described more fully hereinafter.
[0010] It is desirable to achieve more precise control of switched-mode-generated RF signals, including amplitude-modulated signals, such that the aforementioned benefits of switched-mode power amplifiers may be more fully realized.
SUMMARY OF THE INVENTION
[0011] This invention controls and modulates switched-mode power amplifiers to enable the production of signals that include amplitude modulation (and possibly, but not necessarily, phase modulation), the average power of which may be controlled over a potentially wide range.
[0012] In order to produce amplitude-modulated signals, the DC switch supply voltage is replaced by a time-varying switch supply signal that is related to the desired amplitude modulation. This switch supply signal can be either the desired amplitude modulation signal itself or a pre-distorted version thereof, where the pre-distortion is such that the output signal has the desired amplitude modulation. In the latter case, the pre-distortion corrects for amplitude non-linearity (so-called AM/AM distortion) in the switch and/or the resonant network.
[0013] The foregoing modification alone, however, may be insufficient to provide as much dynamic range in the output signal as may be desired. Also, the modification may not be sufficient to maintain dynamic range in the amplitude modulation while adjusting the average power of the output signal. Both of these problems are caused by the undesirable leakage signal described previously; its contribution to the output is largely independent of the level of the switch supply signal. That is, the switch supply signal may be reduced to zero volts (the minimum possible amplitude), yet the output signal will still be at a relatively high level; below some point, the amplitude modulation imparted through the switch supply signal is manifest less and less in the output signal.
[0014] Similarly, the severity of amplitude-dependent phase shift (so-called AM/PM distortion) increases as the switch supply signal decreases. This effect arises because the leakage of the switch control signal is out of phase relative to the desired signal. As the switch supply signal decreases, the desired signal decreases as well, whereas the leakage signal does not; since these two signals are out of phase, the phase of their sum is increasingly dominated by the phase of the leakage signal. This invention, in one aspect thereof, modifies the switched-mode power amplifier by adjusting the amplitude of the switch control signal to reduce the undesirable leakage effect. As a result, it becomes possible to produce output signals having average power anywhere within a wide range, or to greatly increase the dynamic range over which amplitude modulation may be produced at a given average power level, or both.
BRIEF DESCRIPTION OF THE DRAWING FIGURES
[0015] The present invention may be further understood from the following description in conjunction with the appended drawing figures. In the figures:
[0016] FIG. 1 is a block diagram of a known switched-mode power amplifier in a variable power supply voltage is applied in common to multiple stages;
[0017] FIG. 2 is a block diagram of a switched-mode power amplifier without amplitude modulation capability;
[0018] FIG. 3 is a diagram comparing AM/PM distortion in a switched-mode power amplifier without a countermeasure of the invention and with a countermeasure of the invention;
[0019] FIG. 4 is a waveform diagram of waveforms in the circuit of FIG. 2 ;
[0020] FIG. 5 is one possible circuit that may be used to control the application of power to one or more power amplifier stages;
[0021] FIG. 6 is another possible circuit that may be used to control the application of power to one or more power amplifier stages;
[0022] FIG. 7 is still another possible circuit that may be used to control the application of power to one or more power amplifier stages;
[0023] FIG. 8 is a block diagram of a generalized efficient power amplifier structure;
[0024] FIG. 9 is a block diagram of a switched-mode power amplifier having amplitude modulation capability;
[0025] FIG. 10 is a waveform diagram of waveforms in the circuit of FIG. 9 ;
[0026] FIG. 11 is another waveform diagram of waveforms in the circuit of FIG. 9 ;
[0027] FIG. 12 is a more detailed diagram of an exemplary embodiment of the switched-mode power amplifier of FIG. 9 ; and
[0028] FIG. 13 is a waveform diagram of waveforms in the circuit of FIG. 12 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] Referring now to FIG. 2 , a block diagram is shown of a switched-mode power amplifier. A switch 201 is coupled to a resonant network 205 and to power control logic 215 , which is coupled in turn to a DC supply 203 . The resonant network is coupled to a load 207 . Control of the switch 201 is accomplished using a control signal 209 , applied to an amplifier 211 . The amplifier 211 produces a switch control signal 219 , which is applied to the switch 201 . As the switch 201 is opened and closed responsive to the control signal 209 , the resonant network 205 shapes the switch voltage to produce a desired output signal 213 .
[0030] In the amplifier of FIG. 2 , the signals 209 and 219 are constant-amplitude (CA) signals (i.e., oscillatory signals having a constant peak amplitude) that may be phase-modulated. The amplitude of the switch control signal 219 is set by the power control logic 215 . The power control logic 215 also controls a DC supply voltage 216 produced by the DC supply 203 and supplied to the switch 201 . As the power control logic 215 causes the DC supply voltage 216 to increase, the peak voltage of the oscillatory signals developed within the resonant network 205 and subsequently delivered to the load 207 also increases. Similarly, as the power control logic 215 causes the DC supply voltage 216 to decrease, the peak voltage of the oscillatory signals developed within the resonant network 205 and subsequently delivered to the load 207 also decreases.
[0031] Further details of the amplifier chain of FIG. 2 in accordance with an exemplary embodiment of the invention are described in the foregoing copending U.S. patent applications. In addition, a bias control arrangement may be used to achieve optimal bias of the switch 201 under various conditions as described more fully in U.S. patent application Ser. No.______ (Dkt. 101006VBC.US), filed on even date herewith and incorporated herein by reference.
[0032] In accordance with one aspect of the invention, a signal 218 is used to control the amplitude of the switch control signal 219 in a coordinated manner with control of the DC supply voltage 216 , thereby avoiding excess leakage of the switch control signal 219 through the switch 201 and into the resonant network 205 .
[0033] More particularly, in any physical embodiment, a stray (unintended) capacitance 212 around the switch 201 is unavoidably present. This stray capacitance provides a leakage path for the switch control signal 219 to leak into the resonant network 205 , where it mixes with the desired switch output signal. Since the switch control signal 219 is out-of-phase with the desired switch output signal, a large phase shift will occur at the switch output when the desired output signal magnitude is near to or smaller than that of the leakage signal. This effect is shown in FIG. 3 , which depicts output phase and output magnitude as parametric functions of desired magnitude (i.e., as desired magnitude decreases, the curves of FIG. 3 are traced out in the counter-clockwise direction). In the illustrated case, signal leakage is assumed to be 35 dB below the maximum output signal (1.7%), at a relative phase shift of −170 degrees. If the switch control signal is not reduced (line A), then the amplifier output signal suffers severe AM-PM (and AM-AM) distortion when the desired output magnitude is less than 10% of the peak output magnitude.
[0034] This effect may be counteracted, for lower amplitude output signals (e.g., less than 10% of the peak output magnitude), by correspondingly reducing the switch control signal (e.g., to 10% of its original value). As FIG. 3 shows, this measure essentially removes the AM-PM and AM-AM distortion from the desired output signal (line B). In principle, this technique can be extended to arbitrarily low desired output signal magnitudes.
[0035] For illustration purposes, consider the need to produce a constant-amplitude RF signal in a time-slotted network, in which the output power may very from slot to slot. In the amplifier of FIG. 2 , this manner of operation may be achieved by holding the supply voltage 216 constant during a given time slot, and by holding the peak amplitude of the control signal constant during the time slot as illustrated in FIG. 4 . As a result, the peak amplitude of the output signal 213 is constant during a given time slot. Note that when the supply voltage 216 is is at a low level, the control signal 219 is also at a correspondingly low level (e.g., time slot (N)). In this manner, the low-distortion characteristic of line B of FIG. 3 is achieved.
[0036] Various specific circuits that may be used within the power control logic 215 of FIG. 2 to control the application of power to the amplifier stages are shown in FIG. 5 , FIG. 6 , and FIG. 7 , respectively.
[0037] Referring first to FIG. 5 , a DC supply voltage V SUPPLY is applied to the emitter of a PNP bipolar transistor Q in common-emitter configuration. The DC supply voltage may be unregulated or, alternatively, may have been regulated/conditioned to an appropriate DC level for a desired instantaneous output power using, for example, a switching power supply in combination with a linear regulator as described in greater detail in the aforementioned patent applications. The collector of the transistor Q is connected through a resistive divider network Rl, R 2 to ground. An operational amplifier 501 is connected to receive a power-setting command signal 523 on a negative input and to receive on its positive input a voltage developed at the junction of the resistors R 1 and R 2 . The operational amplifier 501 produces an output signal that is applied to the base of the transistor Q. In operation, the transistor functions as a controlled resistance, under control of the operational amplifier 501 , to deliver a precisely-controlled voltage to multiple amplifier stages, including, for example, a driver stage 503 (responsive to an RF signal 509 analogous to signal 209 of FIG. 2 ) and a final stage 505 . In the case of the driver stage 503 , the controlled voltage from the transistor Q is applied through a resistor R 3 to account for the sizing of the driver amplifier relative to the final amplifier. The foregoing circuit realizes. fast control and may be used in conjunction with or in lieu of separate DC regulation circuitry.
[0038] One or more additional driver stages may be provided as shown, for example, in FIG. 6 . In FIG. 6 , the supply voltage of an initial stage 607 is controlled less stringently. A number of discrete supply voltages (V 1 , V 2 , . . . , V N ) are applied to a switch 609 , which is controlled to select a desired one of the discrete voltages. Control of the final stage 605 and the immediately preceding driver stage 603 may remain as previously described.
[0039] If a desired output signal has a large dynamic range, common control of the driver and final stages may prove insufficient. Referring to FIG. 7 , separate control is provided for each of multiple amplifier stages. This arrangement may be extended to any arbitrary number of stages.
[0040] Referring again to FIG. 2 , in the case of constant amplitude output signals, the amplifier as shown is effective to provide efficient amplification and power control. However, it does not provide for amplitude modulation.
[0041] Referring now to FIG. 8 , a generalized efficient power amplifier structure is shown, enabling control of multiple stages to achieve complex control, including amplitude modulation, of an amplifier output signal. In FIG. 8 , an RF input signal, RF in , is applied to an amplifier chain including N stages. The amplifier chain produces an RF output signal, RF out . Supply voltages for each of the stages are independently controlled. One or more control blocks receive a DC supply voltage and, responsive to control signals from a controller (not shown), produce separate power supply voltages for each of the N amplifier stages. In the example of FIG. 8 , two control blocks are shown, a power/burst control block 801 and a modulation control block 803 . However, the functions of the control blocks may be readily consolidated or sub-divided as will be apparent to one of ordinary skill in the art.
[0042] Optionally, independent bias signals may be supplied to each one of the stages. In one embodiment, possible values of the bias signal include a value that turns the stage off, e.g., places the active element of the stage in a high-impedance state. In addition, each stage may optionally include a controlled bypass element or network, shown in FIG. 8 as a resistor connecting the input and output terminals of a stage. Such a bypass may allow performance of an amplifier stage at low input signal levels to be more completely characterized and controlled. In particular, since circuit parasitics unavoidably create the effect of a bypass, by explicitly providing a bypass, it may be designed in such a manner as to dominate parasitic effects.
[0043] A particular case of the generalized amplifier structure of FIG. 8 will now be described in detail.
[0044] Referring to FIG. 9 , an amplifier is shown that provides the advantages of the amplifier of FIG. 2 and additionally provides for amplitude modulation. In FIG. 9 , there is provided a switch 901 , a DC supply 903 , a resonant network 905 , a load 907 , a control signal 909 , a control signal amplifier 911 , an output signal 913 and power control logic 915 , corresponding generally to and given like designations as elements in FIG. 2 . The control signal amplifier 911 is responsive to a drive control signal 918 to produce a switch control signal 919 In FIG. 9 , however, there is additionally provided an amplitude modulator 917 responsive to an AM signal 923 . Instead of the power control logic 915 controlling the control signal amplifier 911 directly (as in FIG. 2 ), the power control logic 915 is coupled to the amplitude modulator 917 , which is responsive to the power control logic 915 to control the control signal amplifier 911 . Under the control of the amplitude modulator 917 , the control signal amplifier 911 produces a switch control signal 919 that is applied to the switch 901 . The DC supply 903 is coupled to the amplitude modulator 917 , which is responsive to the AM signal 923 to modify the supply voltage appropriately and apply a resulting switch supply signal 921 to the switch 901 .
[0045] Two cases of operation of the amplifier of FIG. 9 may be distinguished. One case is shown in FIG. 10 , in which amplitude modulation is achieved solely through variation of the switch supply signal 921 , and power control is achieved jointly through variation of the DC supply 903 and variation of the switch control signal 919 (via signal 918 ). During a timeslot (N−1), the peak amplitude of the switch control signal 919 remains constant. During this time, the peak amplitude of the control signal 909 also remains constant. The switch supply signal 921 , on the other hand, has impressed upon it amplitude modulation signal variations. As a result, the output signal 913 exhibits corresponding amplitude variations. During timeslot (N), the amplitudes of the control signal 909 and the switch control signal 919 are constant at a lower level, and a DC supply voltage 904 (not shown in FIG. 10 ) is also constant at a lower level, indicative of a lower desired output power level. Different amplitude modulation signal variations are impressed upon the switch supply signal 921 and are manifest in the amplitude of the output signal 913 . During timeslot (N+1), the level of the control signal 909 and the switch control signal 919 are raised back up, as is the DC supply voltage 904 , corresponding to a higher desired output power level. The constant peak amplitude of the switch control signal 919 is set higher for higher desired output power levels, and set lower for lower desired output power levels, so that the switch 901 is successfully turned on and off as needed while minimizing the undesirable leakage of the switch control signal 919 through the switch 901 and into the resonant network 905 .
[0046] At lower power levels, to avoid excess leakage of the switch control signal 919 into the output signal 913 , it may be necessary to achieve amplitude modulation of the output signal through coordinated variation of both the switch supply signal 921 and the switch control signal 919 . This represents the second case of operation previously referred to, and is illustrated in FIG. 11 . In particular, FIG. 11 shows examples of different relationships between amplitude modulation of the switch supply signal 921 and amplitude modulation of the switch control signal 919 . Power control and amplitude modulation of both the switch supply signal 921 and the switch control signal 919 are applied as needed to extend the dynamic range of the output signal 913 . In an exemplary embodiment, amplitude modulation of the switch control signal 919 is applied only when the AM signal 923 dips below a threshold that is power-level dependent.
[0047] Timeslot (N−1) illustrates the case in which the AM signal 923 is below the power-level-dependent threshold (indicated in dashed lines in the upper frame of the FIG. 11 ) for the duration of the timeslot. Hence, the switch control signal 919 is amplitude modulated along with the switch supply signal 921 throughout the duration of the timeslot. In timeslot (N), during both an initial portion of the timeslot and during a final portion of the timeslot, the AM signal 923 is assumed to be above the threshold. Hence, during these portions of the timeslot, the switch control signal 919 is not amplitude modulated. (In the middle frame of FIG. 11 , the dashed lines indicate the nominal amplitude of the switch control signal 919 when the AM signal 923 is above the threshold.) During an intermediate portion of the timeslot, however, the AM signal 923 is assumed to be below the threshold. During this portion of the timeslot, the switch control signal 919 is amplitude modulated along with the switch supply signal 921 . Finally, in timeslot (N+1), the AM signal 923 is assumed to be above the threshold throughout the duration of the timeslot. The amplitude (peak-to-peak) of the switch control signal 919 is therefore held constant throughout the duration of the timeslot. Note that the actual amplitude modulation is still solely impressed on the output signal 913 by switch supply signal 921 . Variation of signal 918 and the resulting variation of signal 919 in concert with signal 921 is performed soley to reduce leakage. As such, the precision required of signal 918 is greatly reduced from that required of signal 921 .
[0048] Referring now to FIG. 12 , a more detailed diagram is shown of an amplifier in accordance with an exemplary embodiment of the invention, in which like elements are assigned like reference numerals as in FIG. 9 . In the embodiment of FIG. 12 , the control signal amplifier 1211 and the switch 1201 are provided as first and second amplifier stages, a “gain” stage and a “switch” stage, respectively. The gain stage 211 may be implemented in a variety of ways. One implementation is a conventional gain-controlled linear CCS (controlled current source) amplifier of widely-understood classes A, AB, B and C. An alternative implementation is a smaller-scale switch-mode stage of a type described in the aforementioned copending U.S. applications.
[0049] Within dashed line block 917 are shown further details of one embodiment of the amplitude modulator 917 of FIG. 9 . In response to AM signal samples 1223 and to a signal 1232 from the power control logic 1215 , the AM logic 1231 calculates appropriate supply levels for the first amplifier stage 1211 and the second amplifier stage 1201 .
[0050] In the case of the first amplifier stage 1211 , a DC supply voltage is supplied through a transistor 1235 - 1 . Base drive to the transistor 1235 - 1 is controlled by the AM logic 1231 through a DAC (digital to analog converter) 1233 - 1 . Hence the DAC 1233 - 1 sets the level of the switch control signal 1219 seen by the second amplifier stage 1201 . Similarly, in the case of the second amplifier stage 1201 , a DC supply voltage is supplied through a transistor 1235 - 2 . Base drive to the transistor 1235 - 2 is controlled by the AM logic 1231 through a DAC 1233 - 2 .
[0051] In an exemplary embodiment, the output of the DAC 1233 - 1 is given by the following rule:
DAC 1 ( t ) = v ( p ) , for a ( t ) ≥ m ( p ) = v ( p ) · a ( t ) m ( p ) , for a ( t ) < m ( p )
where a(t) is the AM signal at time t, m(p) is a threshold dependent on the power level p, and v(p) is the nominal output voltage of DAC 1 , for power level p.
[0052] Operation of the amplifier of FIG. 12 in accordance with the foregoing rule is illustrated in FIG. 13 . As seen therein, as the signal a(t) (the amplitude of the AM signal at time t) fluctuates, for a first period of time, the signal exceeds the threshold m(p) for the current power level p. During this period, the voltage DAC 1 (t) is set to the nominal level v(p). Thereafter, the signal a(t) dips below the threshold for a period of time. During this period of time, the voltage DAC 1 (t) is amplitude modulated in accordance with-the fluctuations of the signal a(t). When the signal a(t) again rises above the threshold, the voltage DAC 1 (t) is again set to the nominal level.
[0053] Thus, there has been described an efficient amplifier for RF signals that provides for amplitude modulation over a wide dynamic range. The amplitude of the switch control signal is adjusted to reduce the undesirable leakage effect. As a result, it becomes possible to produce output signals having average power anywhere within a wide-range, or to greatly increase the dynamic range over which amplitude modulation may be produced at a given average power level, or both.
[0054] It will be apparent to those of ordinary skill in the art that the present invention can be embodied in other specific forms without departing from the spirit or essential character thereof. The described embodiments are therefore intended to be in all respects illustrative and not restrictive. The scope of the invention is indicated by the appended claims, rather than the foregoing description, and all changes which come within the meaning and range of equivalents thereof are intended to be embraced therein.
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This invention controls and modulates switched-mode power amplifiers to enable the production of signals that include amplitude modulation (and possibly, but not necessarily, phase modulation), the average power of which may be controlled over a potentially wide range.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] None.
STATEMENT REGARDING FEDERALLY FUNDED RESEARCH AND DEVELOPMENT
[0002] None.
BACKGROUND OF THE INVENTION
[0003] 1. Technical Field
[0004] A silicone gel (‘gel’) is used to seal substrates against gases (such as air) and vapor (such as moisture) penetration. The gel is fabricated to be form stable and has sufficient tack to adhere when applied to a first substrate until a second substrate is fastened thereto. The gel is useful in construction applications such as window framing and flashing, as well as indoor sealing applications, such as sealing at the perimeter of bathtubs, shower enclosures, and sinks The gel is useful in marine applications such as sealing windows and/or through holes in boat hulls.
[0005] 2. Background
[0006] Various products and methods are known in the art for sealing framing members to minimize gas and vapor penetration. Wet sealant has been used in the past. However, wet sealant suffers from the drawback of being messy to apply. Furthermore, in framing applications, the sealant may be applied and then compressed between framing members. During this compression, the excess is squeezed out and must be wiped off and discarded. Furthermore, volatile organic compounds (VOCs) may be released into the atmosphere during curing of the wet sealant.
[0007] Alternatively, a sheet of silicone rubber or foam may be cut and then the resulting piece may be placed between the framing members and compressed when the members are fastened together. This method eliminates the VOC emissions because the silicone rubber is cured before application to the substrates. However, silicone rubber may suffer from the drawback of lacking sufficient tack (self adhesion) to stay on the first substrate during the fastening process when, for example, the silicone rubber is placed against a substrate vertically.
[0008] A sheet or tape of silicone foam with adhesive on its sides has also been proposed. However, this product suffers from the drawback that it cannot be trimmed once applied to the substrate. If trimmed, the foam can delaminate from the adhesive, leaving an adhesive residue or film on the substrate, which can cause dirt pick up and poor appearance.
[0009] There is a continuing need in the construction industry to produce products with better aesthetics, reduced waste, and reduced VOC emissions.
BRIEF SUMMARY OF THE INVENTION
[0010] A method for forming a gas and vapor resistant seal between substrates is disclosed. The method comprises:
i) applying a form stable gel to a first substrate, and ii) connecting the first substrate and a second substrate;
thereby forming a seal between the first substrate and the second substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is an example of a form stable gel with release liners on its surfaces.
[0014] FIG. 2 is a process flow diagram for making the form stable gel.
[0015] FIG. 3 shows photographs of a method for using the form stable gel to seal an aluminum frame.
[0016] FIG. 4 shows photographs of an additional method step for the method of FIG. 3 .
REFERENCE NUMERALS
[0000]
100 Form Stable Gel
101 Support
102 Layer of Gel
103 Release Liner
201 Fiberglass Mesh Payoff
202 Primary Coater
203 Drum of Base
204 Drum of Curing Agent
205 Drum Pumps
206 Static Mixer
207 Mixer
208 Storage Tank
209 Fiberglass Mesh
210 Primary Heater
211 Form Stable Gel
212 Release Liner Feed Roll
213 Product Take Up
DETAILED DESCRIPTION OF THE INVENTION
[0034] All amounts, ratios, and percentages are by weight, unless otherwise indicated. The articles ‘a’, ‘an’, and ‘the’ each refer to one or more, unless otherwise indicated. All viscosity measurements were taken at 25° C. unless otherwise stated.
Gel
[0035] The curable silicone composition used in the method described above cures to form a gel that is form stable. The curing mechanism of the curable silicone composition may be any cure mechanism that does not release by products that foul the substrates between which the gel is interposed. For example, the curable silicone composition may be addition reaction curable such as a thermally curable one part composition or a two part composition that cures at ambient or elevated temperature, a peroxide curable silicone composition, a radiation curable silicone composition, or a combination thereof.
[0036] The gel used in the method and article described herein is form stable. For purposes of this application, the term ‘gel’ means a lightly crosslinked polymer network. A gel has a hardness value lower than hardness typically associated with a silicone rubber, which has a higher crosslink density than a gel. The gel may have a hardness ranging from 30 to 70 on a Shore 00 scale as measured according to ASTM Standard D 2240-05 using a durometer. Alternatively, the gel may have a hardness ranging from 50 grams to 300 grams, alternatively 100 grams to 200 grams, as measured by the method of reference example 2. These methods permit hardness measurements based on indentation.
[0037] For purposes of this application, ‘form stable’ means that when the gel is manually applied to a substrate, the gel will maintain its shape for an amount of time sufficient to attach a second substrate to the first substrate. Gels are not always form stable, however, the gel can be made form stable by the addition of an extending filler to the curable silicone composition, by the use of a support, or a combination thereof. The gel may be a commercially available silicone gel, such as GT-1700 from Dow Corning Corporation of Newark, CA, USA.
[0038] Alternatively, the gel may be prepared from a curable silicone composition. The curable silicone composition may comprise: (A) a base polymer, optionally (B) a crosslinker, and an amount sufficient to accelerate curing of the composition of (C) a catalyst, where the ingredients and amounts are selected such that a cured product of the curable silicone composition is a gel.
Hydrosilylation Curable Composition
[0039] The curable silicone composition used to form the gel described above may comprise a hydrosilylation curable composition. The hydrosilylation curable composition comprises (A′) a base polymer having an average of at least two aliphatically unsaturated organic groups per molecule, (B′) a crosslinker having an average of at least two silicon-bonded hydrogen atoms per molecule, and (C′) a hydrosilylation catalyst, where the ingredients and amounts are selected such that a product prepared by curing the composition is a gel.
Ingredient (A′) Base Polymer
[0040] Ingredient (A′) of the hydrosilylation curable composition may comprise a polyorganosiloxane having an average of at least two aliphatically unsaturated organic groups per molecule. Ingredient (A′) may have a linear or branched structure. Alternatively, ingredient (A′) may have a linear structure. Ingredient (A′) may be a homopolymer or a copolymer. The aliphatically unsaturated organic groups may be alkenyl exemplified by, but not limited to, vinyl, allyl, butenyl, and hexenyl. The unsaturated organic groups may be alkynyl groups exemplified by, but not limited to, ethynyl, propynyl, and butynyl. The aliphatically unsaturated organic groups in ingredient (A′) may be located at terminal, pendant, or both terminal and pendant positions. Alternatively, the aliphatically unsaturated organic groups in ingredient (A′) may be located at terminal positions.
[0041] The remaining silicon-bonded organic groups in ingredient (A′) may be monovalent organic groups free of aliphatic unsaturation. These monovalent organic groups may have 1 to 20 carbon atoms, alternatively 1 to 10 carbon atoms, and are exemplified by, but not limited to hydrocarbon groups including alkyl groups such as methyl, ethyl, propyl, pentyl, octyl, undecyl, and octadecyl; cycloalkyl groups such as cyclopentyl and cyclohexyl; and aromatic groups such as phenyl, tolyl, xylyl, benzyl, and 2-phenylethyl.
[0042] Ingredient (A′) may comprise a polydiorganosiloxane of
[0000] R 1 2 R 2 SiO(R 1 2 SiO) a (R 1 R 2 SiO) b SiR 1 2 R 2 , Formula (I)
[0000] R 1 3 SiO(R 1 2 SiO) c (R 1 R 2 SiO) d SiR 1 3 , Formula (II)
[0000] or a combination thereof.
[0043] In Formulae (I) and (II), each R 1 is independently a monovalent organic group free of aliphatic unsaturation and each R 2 is independently an aliphatically unsaturated organic group. The subscripts, a, b, c, and d have values sufficient to give the polydiorganosiloxane a viscosity ranging from 100 to 20,000 mPa·s as measured by Brookfield RVT CP-52 viscometer at 5 rpm.
[0044] Alternatively, subscript a may have an average value ranging from 2 to 2000, subscript b may have an average value ranging from 0 to 2000, subscript c may have an average value ranging from 0 to 2000, and subscript d may have an average value ranging from 2 to 2000. Suitable monovalent organic groups for R 1 include, but are not limited to, alkyl such as methyl, ethyl, propyl, pentyl, octyl, undecyl, and octadecyl; cycloalkyl such as cyclohexyl; and aryl such as phenyl, tolyl, xylyl, benzyl, and 2-phenylethyl. Each R 2 is independently an aliphatically unsaturated monovalent organic group. R 2 is exemplified by alkenyl groups such as vinyl, allyl, and butenyl and alkynyl groups such as ethynyl and propynyl.
[0045] Ingredient (A′) may comprise polydiorganosiloxanes such as
i) dimethylvinylsiloxy-terminated polydimethylsiloxane, ii) dimethylvinylsiloxy-terminated poly(dimethylsiloxane/methylvinylsiloxane), iii) dimethylvinylsiloxy-terminated polymethylvinylsiloxane, iv) trimethylsiloxy-terminated poly(dimethylsiloxane/methylvinylsiloxane), v) trimethylsiloxy-terminated polymethylvinylsiloxane, vi) dimethylvinylsiloxy-terminated poly(dimethylsiloxane/methylphenylsiloxane), vii) dimethylvinylsiloxy-terminated poly(dimethylsiloxane/diphenylsiloxane), viii) phenyl,methyl,vinyl-siloxy-terminated polydimethylsiloxane, ix) dimethylhexenylsiloxy-terminated polydimethylsiloxane, x) dimethylhexenylsiloxy-terminated poly(dimethylsiloxane/methylhexenylsiloxane), xi) dimethylhexenylsiloxy-terminated polymethylhexenylsiloxane, xii) trimethylsiloxy-terminated poly(dimethylsiloxane/methylhexenylsiloxane), xiii) a combination thereof.
[0059] Methods of preparing polydiorganosiloxane fluids suitable for use as ingredient (A′), such as hydrolysis and condensation of the corresponding organohalosilanes or equilibration of cyclic polydiorganosiloxanes, are well known in the art.
[0060] Ingredient (A′) can be a single base polymer or a combination comprising two or more base polymers that differ in at least one of the following properties: structure, viscosity, average molecular weight, siloxane units, and sequence.
Ingredient (B′) Crosslinker
[0061] Ingredient (B′) in the hydrosilylation curable composition is a crosslinker having an average of at least two silicon-bonded hydrogen atoms per molecule. The amount of ingredient (B′) in the hydrosilylation cure package is sufficient to crosslink the composition to form a gel, as described above. The amount of ingredient (B′) will vary depending on the structure and vinyl content of ingredient (A′) and the structure and SiH content of ingredient (B′), however, the amount may range from 0.5 part to 15 parts, alternatively 1 part to 5 parts, per 100 parts by weight of ingredient (A′). Ingredient (B′) can be a homopolymer or a copolymer. Ingredient (B′) can have a linear, branched, or cyclic structure. The silicon-bonded hydrogen atoms in ingredient (B′) can be located at terminal, pendant, or at both terminal and pendant positions.
[0062] Ingredient (B′) may comprise siloxane units including, but not limited to, HR 3 2 SiO 1/2 , R 3 3 SiO 1/2 , HR 3 SiO 2/2 , R 3 2 SiO 2/2 , R 3 SiO 3/2 , and SiO 4/2 units. In the preceding formulae, each R 3 is independently selected from monovalent organic groups, such as those described above.
[0063] Ingredient (B′) may comprise a polydiorganohydrogensiloxane of the formula
[0000] R 4 3 SiO(R 4 2 SiO) e (R 4 HSiO) f SiR 4 3 , (VI)
[0000] R 4 2 HSiO(R 4 2 SiO) g (R 4 HSiO) h SiR 4 2 H, or (VII)
[0000] (VIII) a combination thereof.
[0064] In the formulae above, the subscripts, e, f, g, and h have values sufficient to give the polydiorganohydrogensiloxane a viscosity ranging from 10 mPa·s to 500 mPa·s. Alternatively, subscript e may have an average value ranging from 0 to 2000, subscript f may have an average value ranging from 2 to 2000, subscript g may have an average value ranging from 0 to 2000, and subscript h may have an average value ranging from 0 to 2000. Each R 4 is independently a monovalent organic group. Suitable monovalent organic groups include alkyl such as methyl, ethyl, propyl, pentyl, octyl, undecyl, and octadecyl; cycloalkyl such as cyclohexyl; alkenyl such as vinyl, allyl, butenyl, and hexenyl; alkynyl such as ethynyl, propynyl, and butynyl; and aryl such as phenyl, tolyl, xylyl, benzyl, and 2-phenylethyl.
[0065] Ingredient (B′) is exemplified by
a) dimethylhydrogensiloxy-terminated polydimethylsiloxane, b) dimethylhydrogensiloxy-terminated poly(dimethylsiloxane/methylhydrogensiloxane), c) dimethylhydrogensiloxy-terminated polymethylhydrogensiloxane, d) trimethylsiloxy-terminated poly(dimethylsiloxane/methylhydrogensiloxane), e) trimethylsiloxy-terminated polymethylhydrogensiloxane, and f) a combination thereof.
[0072] Ingredient (B′) may be a combination of two or more SiH functional crosslinkers that differ in at least one of the following properties: structure, average molecular weight, viscosity, siloxane units, and sequence. Methods of preparing linear, branched, and cyclic organohydrogenpolysiloxanes suitable for use as ingredient (B′), such as hydrolysis and condensation of organohalosilanes, are well known in the art. Methods of preparing organohydrogenpolysiloxane resins suitable for use as ingredient (B′) are also well known as exemplified in U.S. Pat. Nos. 5,310,843; 4,370,358; and 4,707,531.
Ingredient (C′) Hydrosilylation Catalyst
[0073] Ingredient (C′) of the hydrosilylation curable composition is a hydrosilylation catalyst. Ingredient (C′) is added in an amount ranging from 0.1 ppm to 1000 ppm of platinum group metal, alternatively 1 ppm to 500 ppm, alternatively 2 ppm to 200 ppm, and alternatively 5 ppm to 150 ppm, based on the weight of the hydrosilylation curable composition.
[0074] Suitable hydrosilylation catalysts are known in the art and are commercially available. Ingredient (C′) may comprise a platinum group metal selected from platinum, rhodium, ruthenium, palladium, osmium or iridium metal or organometallic compound thereof, or a combination thereof. Ingredient (C′) is exemplified by compounds such as chloroplatinic acid, chloroplatinic acid hexahydrate, platinum dichloride, and complexes of said compounds with low molecular weight organopolysiloxanes or platinum compounds microencapsulated in a matrix or coreshell type structure. Complexes of platinum with low molecular weight organopolysiloxanes include 1,3-diethenyl-1,1,3,3-tetramethyldisiloxane complexes with platinum. These complexes may be microencapsulated in a resin matrix. When the catalyst is a platinum complex with a low molecular weight organopolysiloxane, the amount of catalyst may range from 0.01% to 0.4% based on the weight of the hydrosilylation curable composition.
[0075] Suitable hydrosilylation catalysts for ingredient (C′) are described in, for example, U.S. Pat. Nos. 3,159,601; 3,220,972; 3,296,291; 3,419,593; 3,516,946; 3,814,730; 3,989,668; 4,784,879; 5,036,117; and 5,175,325 and EP 0 347 895 B. Microencapsulated hydrosilylation catalysts and methods of preparing them are known in the art, as exemplified in U.S. Pat. Nos. 4,766,176 and 5,017,654.
Peroxide Cure Packages
[0076] Alternatively, the curable silicone composition may comprise a peroxide curable composition. The peroxide curable composition may comprise (A″) a base polymer having an average of at least two aliphatically unsaturated organic groups per molecule, optionally (B″) a crosslinkers, and (C″) a catalyst, where the ingredients and amounts are selected such that a cured product of the composition is a gel.
Ingredient (A″) Base Polymer
[0077] Ingredient (A″) of the peroxide cure package comprises a polydiorganosiloxane having an average of at least two aliphatically unsaturated organic groups per molecule. Ingredient (A″) may be a homopolymer or a copolymer. The aliphatically unsaturated organic groups may be alkenyl exemplified by, but not limited to, vinyl, allyl, butenyl, and hexenyl. The aliphatically unsaturated organic groups may be alkynyl groups exemplified by, but not limited to, ethynyl, propynyl, and butynyl. The unsaturated organic groups in ingredient (A″) may be located at terminal, pendant, or both terminal and pendant positions. Alternatively, the aliphatically unsaturated organic groups in ingredient (A″) may be located at terminal positions.
[0078] The remaining silicon-bonded organic groups in ingredient (A′″) may be monovalent organic groups free of aliphatic unsaturation. These monovalent organic groups are exemplified by, but not limited to alkyl groups such as methyl, ethyl, propyl, pentyl, octyl, undecyl, and octadecyl; cycloalkyl groups such as cyclohexyl; and aromatic groups such as phenyl, tolyl, xylyl, benzyl, and 2-phenylethyl.
[0079] Ingredient (A″) may comprise a polydiorganosiloxane of
[0000] R 5 2 R 6 SiO(R 5 2 SiO) i (R 5 R 6 SiO) j SiR 5 2 R 6 , Formula (IX)
[0000] R 5 3 SiO(R 5 2 SiO) k (R 5 R 6 SiO) m SiR 5 3 , Formula (X)
[0000] or a combination thereof.
[0080] In formulae (IX) and (X), each R 5 is independently a monovalent organic group free of aliphatic unsaturation, and each R 6 is independently an aliphatically unsaturated organic group. In formulae above, the subscripts, i, j, k, and m have values sufficient to give the polydiorganohydrogensiloxane a viscosity ranging from 100 mPa·s to 15,000 mPa·s. Alternatively, subscript i may have an average value of at least 2, subscript j may be 0 or a positive number, subscript k may be 0 or a positive number, and subscript m has an average value of at least 2. Suitable monovalent organic groups for R 5 include, but are not limited to, alkyl such as methyl, ethyl, propyl, pentyl, octyl, undecyl, and octadecyl; cycloalkyl such as cyclohexyl; and aryl such as phenyl, tolyl, xylyl, benzyl, and 2-phenylethyl. Each R 6 is independently an aliphatically unsaturated monovalent organic group. R 6 is exemplified by alkenyl groups such as vinyl, allyl, and butenyl and alkynyl groups such as ethynyl and propynyl.
[0081] Methods of preparing polydiorganosiloxane fluids suitable for use as ingredient (A″), such as hydrolysis and condensation of the corresponding organohalosilanes or equilibration of cyclic polydiorganosiloxanes, are well known in the art. Ingredient (A″) may be a combination of two or more polydiorganosiloxanes that differ in at least one of the following properties: structure, average molecular weight, viscosity, siloxane units, and sequence.
Optional Ingredient (B″) Crosslinker
[0082] Ingredient (B″) is a crosslinker may optionally be added to the peroxide curable composition. The amount of ingredient (B″) in the composition may range from 0 to 15 parts per 100 parts by weight of ingredient (A″). Ingredient (B″) may comprise a polydiorganohydrogensiloxane having an average of at least two silicon-bonded hydrogen atoms per molecule.
[0083] Ingredient (B″) may comprise a polydiorganohydrogensiloxane of the formula
[0000] R 7 3 SiO(R 7 2 SiO) n (R 7 HSiO) o SiR 7 3 , (XI)
[0000] R 7 2 HSiO(R 7 2 SiO) p (R 7 HSiO) q SiR 7 2 H, or (XII)
[0000] (XIII) a combination thereof.
[0084] In the formulae above, the subscripts, n, o, p, and q have values sufficient to give the polydiorganohydrogensiloxane a viscosity ranging from 10 mPa·s to 500 mPa·s. Alternatively, subscript n may have an average value ranging from 0 to 2000, subscript o may have an average value ranging from 2 to 2000, subscript p may have an average value ranging from 0 to 2000, and subscript q has an average value ranging from 0 to 2000, with the provisos that (n+o)<2000 and (p+q)<2000. Each R 7 is independently a monovalent organic group. Suitable monovalent organic groups include alkyl such as methyl, ethyl, propyl, pentyl, octyl, undecyl, and octadecyl; cycloalkyl such as cyclohexyl; alkenyl such as vinyl, allyl, butenyl, and hexenyl; alkynyl such as ethynyl, propynyl, and butynyl; and aryl such as phenyl, tolyl, xylyl, benzyl, and 2-phenylethyl.
[0085] Ingredient (B″) is exemplified by
i) dimethylhydrogensiloxy-terminated polydimethylsiloxane, ii) dimethylhydrogensiloxy-terminated poly(dimethylsiloxane/methylhydrogensiloxane), iii) dimethylhydrogensiloxy-terminated polymethylhydrogensiloxane, iv) trimethylsiloxy-terminated poly(dimethylsiloxane/methylhydrogensiloxane), v) trimethylsiloxy-terminated polymethylhydrogensiloxane, vi) a combination thereof.
[0092] Methods of preparing linear, branched, and cyclic organohydrogenpolysiloxanes suitable for use as ingredient (B′), such as hydrolysis and condensation of organohalosilanes, are well known in the art. Ingredient (B″) may be a combination of two or more polydiorganohydrogensiloxanes that differ in at least one of the following properties: structure, average molecular weight, viscosity, siloxane units, and sequence.
Ingredient (C″) Catalyst
[0093] Ingredient (C″) in the peroxide curable composition comprises a peroxide compound. The amount of ingredient (C″) added to the composition depends on the specific peroxide compound selected for ingredient (C″), however, the amount may range from 0.2 to 5 parts per 100 parts by weight of ingredient (A″). Examples of peroxide compounds suitable for ingredient (C″) include, but are not limited to 2,4-dichlorobenzoyl peroxide, dicumyl peroxide, and a combination thereof; as well as combinations of such a peroxide with a benzoate compound such as tertiary-butyl perbenzoate. Suitable peroxide curable composition are known in the art, and are disclosed in, for example, U.S. Pat. No. 4,774,281.
Optional Ingredients
[0094] The curable silicone composition may further comprise one or more additional ingredients in addition to ingredients (A), (B), and (C) described above. The composition may further comprise an additional ingredient selected from the group consisting of (D) an extending filler, (E) a filler treating agent, (F) a stabilizer (e.g., a hydrosilylation cure stabilizer, a heat stabilizer, or a UV stabilizer), (G) a plasticizer, (H), a chain extender, (I) an adhesion promoter, (J) a fungicide, (K) a rheological additive, (L) a flame retardant, (M) a pigment, and a combination thereof.
Optional Ingredient (D) Extending Filler
[0095] The curable silicone composition may optionally further comprise ingredient (D) an extending filler. The amount of extending filler depends on various factors including the type and amount of extending filler, filler treating agent (if any), and the amount of tack desired in the form stable gel. In general, as the amount of extending filler increases, the tack of the form stable gel decreases. The amount of tack desired depends on various factors including customer requirements, however, when the form stable gel will be used in aluminum window frame applications, the amount of tack should be sufficient to allow the form stable gel to stick to a substrate during the method to attach a second substrate thereto. However, when present, the extending filler may be present in an amount ranging from 20% to 90%, alternatively 40% to 70%, alternatively 45% to 70%, and alternatively 45% to 55%, based on the weight of the curable composition.
[0096] Examples of extending fillers include barium sulfate, bentonite, carbon black, clays such as kaolin clay, crushed quartz, diatomaceous earth, graphite, ground calcium carbonate, ground silica, iron oxide, magnesium oxide, sand, talc, titanium dioxide, zinc oxide, zirconia, or a combination thereof. Alternatively, the extending filler may be selected from the group consisting of barium sulfate, bentonite, diatomaceous earth, ground calcium carbonate, kaolin clay, and a combination thereof. Extending fillers are known in the art and commercially available; such as a ground silica sold under the name MIN-U-SIL by U.S. Silica of Berkeley Springs, W. Va. When ground calcium carbonate is used as ingredient (D), the amount of ground calcium carbonate may range from 20% to 80%, alternatively 45% to 55%, based on the weight of the curable silicone composition.
[0097] The extending filler may be added to the curable silicone composition to reduce cost of the gel, to control tack of the gel, or both. The extending filler should be selected such that a sufficient amount of extending filler can be added to the curable silicone composition without forming a paste. Precipitated calcium carbonate is not preferred. Without wishing to be bound by theory, it is thought that precipitated calcium carbonate may contain water in an amount that causes formation of a paste when sufficient amounts of such filler to reduce tack are added to the curable silicone composition, and even treated precipitated calcium carbonate may cause formation of the paste. One skilled in the art would be able to select a suitable extending filler without undue experimentation.
Optional Ingredient (E) Filler Treating Agent
[0098] The curable silicone composition may optionally further comprise ingredient (E), a filler treating agent in an amount ranging from 0.1% to 15%, alternatively 0.5% to 5%, based on the weight of the composition. Ingredient (D), may optionally be surface treated with ingredient (E) before being added to the composition or in situ. Ingredient (E) may comprise an alkoxysilane, an alkoxy-functional oligosiloxane, a cyclic polyorganosiloxane, a hydroxyl-functional oligosiloxane such as a dimethyl siloxane or methyl phenyl siloxane, or a fatty acid such as stearic acid. Examples of stearates include calcium stearate. Examples of filler treating agents and methods for their use are disclosed in, for example, EP 1 101 167 A2 and U.S. Pat. Nos. 5,051,455; 5,053,442; and 6,169,142 (col. 4, line 42 to col. 5, line 2).
Optional Ingredient (F) Stabilizer
[0099] Ingredient (F) is a stabilizer. Stabilizers for hydrosilylation curable compositions are exemplified by acetylenic alcohols such as methyl butynol, ethynyl cyclohexanol, dimethyl hexynol, and 3,5-dimethyl-1-hexyn-3-ol, 1,1-dimethyl-2-propynyl)oxy)trimethylsilane, methyl(tris(1,1-dimethyl-2-propynyloxy))silane, and a combination thereof; cycloalkenylsiloxanes such as methylvinylcyclosiloxanes exemplified by 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,3,5,7-tetramethyl-1,3,5,7-tetrahexenylcyclotetrasiloxane, and a combination thereof; ene-yne compounds such as 3-methyl-3-penten-1-yne, 3,5-dimethyl-3-hexen-1-yne; triazoles such as benzotriazole; phosphines; mercaptans; hydrazines; amines such as tetramethyl ethylenediamine, dialkyl fumarates, dialkenyl fumarates, dialkoxyalkyl fumarates, maleates such as diallyl maleate, and a combination thereof. Alternatively, the stabilizer may comprise an acetylenic alcohol. Suitable hydrosilylation cure package stabilizers are disclosed by, for example, U.S. Pat. Nos. 3,445,420; 3,989,667; 4,584,361; and 5,036,117.
[0100] The amount of stabilizer added to the curable silicone composition will depend on the particular stabilizer used and the composition and amount of crosslinker. However, the amount of hydrosilylation cure stabilizer may range from 0.0025% to 0.025% based on the weight of the hydrosilylation curable composition.
Optional Ingredient (G) Plasticizer
[0101] The plasticizer may optionally be added to the curable silicone composition to improve rheological properties. The plasticizer may be a nonfunctional polyorganosiloxane, such as polydimethylsiloxane having a viscosity ranging from 0.5 cSt to 20 cSt. Suitable plasticizers are commercially available as DOW CORNING® 200 Fluids from Dow Corning Corporation of Midland, Mich., USA.
Optional Ingredient (H) Chain Extender
[0102] The chain extender may optionally be added to the curable silicone composition to improve physical properties of the gel formed by curing the curable silicone composition. The chain extender may be a polydiorganosiloxane terminated with dimethyhydrogensiloxy groups. The chain extender may have a degree of polymerization (Dp) ranging from 3 to 100, alternatively 3 to 10. The amount of chain extender is added in addition to the crosslinker, and may range from 0 to 5% of the curable silicone composition, alternatively 0.25% to 2.5%.
[0103] One skilled in the art would recognize that the curable silicone composition may comprise more than one cure mechanism. For example a dual cure composition that is both radiation curable and hydrosilylation curable is within the scope of this invention. One skilled in the art would be able to select ingredients and amounts thereof in each curable silicone composition described above to prepare a cured product that has a desired consistency as a gel.
Method of Making the Curable Silicone Composition
[0104] The curable silicone composition may be prepared as a one part composition, for example, by combining all ingredients by any convenient means, such as mixing. Alternatively, the curable silicone composition may be prepared as a multiple part composition in which the crosslinker and catalyst are stored in separate parts, and the parts are combined shortly before use of the curable silicone composition. For example, a two part curable silicone composition may be prepared by combining ingredients comprising (A), (C), and any optional ingredients in a base part by any convenient means such as mixing. A curing agent part may be prepared by combining ingredients comprising (A), (B), and any optional ingredients by any convenient means such as mixing. Ingredient (D) may be added to the base part, the curing agent part, or both. The ingredients may be combined at ambient or elevated temperature, depending on the cure mechanism selected. When a two part curable silicone composition is used, the ratio of amounts of base to curing agent may range from 1:1 to 10:1. One skilled in the art would be able to prepare a curable silicone composition without undue experimentation.
Support
[0105] A support may be used to help impart form stability to the gel described above. The support may be a foam or mesh, such as silicone foam, or cotton, fiberglass, or metal mesh.
[0106] Suitable meshes are known in the art and are commercially available. Cotton mesh is exemplified by cheesecloth. BGF Industries, Inc., of Greensboro, N.C., USA manufactures various grades of fiberglass mesh, exemplified by those in Table 1, below in which LOI % means Loss of ingredients.
[0000]
TABLE 1
Fiberglass Mesh
Style/Finish
Average Thickness (inch)
Finish by Weight (LOI %)
1084/A57C
0.0025″ (.06 mm)
2.20%
1080/642
0.0022″ (.05 mm)
0.22%
2112/642
0.0032″ (.08 mm)
0.14%
2116/642
0.0036″ (.09 mm)
0.11%
[0107] The form stable gel may have a release liner on its surface, for example, to protect the gel after manufacture and before use. The release liner is not critical and may be any commercially available release liner capable of protecting the surface of the gel. Examples of suitable release liners include silicone coated release paper, plastic sheets such as polyester such as MYLAR® from LOPAREX, printed release paper from XPEDX, MATTE-FINISH-POLY-21-INCH marketed under the tradename FILCON from The Dow Chemical Company of Midland, Mich., USA; and OS-GEL-1084-A57C-TB-20W (a fiberglass) available from BGF Industries, Inc., of Greensboro, N.C., USA.
[0108] FIG. 1 shows an example of a form stable gel 100 useful as described herein. The form stable gel 100 has a support 101 with layers of gel 102 disposed on opposing sides of the support 101 . The layers of gel 102 have release liners 103 protecting their surfaces. The release liners 103 may be removed shortly before contact of the form stable gel 100 with a substrate.
[0109] The form stable gel, with or without a support (and without release liners) has a thickness sufficient to form a seal between substrates. The thickness depends on various factors including the substrate materials of construction, the surface roughness, and the material to be sealed against (e.g., gas penetration such as air, vapor penetration such as moisture, or both). However, the form stable gel 100 may have a thickness ranging from 0.25 mm to 6 mm, alternatively 0.5 mm to 1.5 mm. When the form stable gel will be used to seal an aluminum window frame, the form stable gel may have sufficient resistance to water penetration to pass the test of preventing leakage when 3 inches of water are sealed by the form stable gel for at least 18 minutes.
[0110] The form stable gel may have a hardness ranging from 30 to 70 on a Shore 00 scale. The form stable gel may have a tack of at least 30 grams as measured with a texture analyzer having a probe descending onto the form stable gel and depressing 2 mm at a speed of 0.2 mm/sec, and thereafter measuring the force to lift the probe off the gel, as described in Reference Example 1, below. Alternatively, tack may range from 30 grams to 200 grams, as measured by the method described in Reference Example 1.
Method
[0111] A method for making the form stable gel is exemplified in FIG. 2 . Fiberglass mesh is fed from payoff 201 to primary coater 202 . The curable silicone composition is prepared by mixing, for example, a base part and a curing agent part as described above. The base may be stored in a drum 203 and the curing agent may be stored in another drum 204 , and the base and curing agent may be pumped with drum pumps 205 to a static mixer 206 . Alternatively, the curable silicone composition may be prepared in a mixer 207 and fed to a storage tank 208 .
[0112] The curable silicone composition may be supplied to primary coater 202 , which coats one side of the fiberglass mesh 209 . The coated mesh 209 is then fed through a primary heater 210 to cure the curable silicone composition and form the form stable gel 211 . The resulting form stable gel 211 can have a release liner (such as the polyester, matte finish paper, or polyethylene described above) put on its surface by feed roll 212 . The resulting form stable gel 211 having the release liners on its surface is collected on a roll at product take up 213 .
[0113] One skilled in the art would recognize that the method described above is exemplary and not limiting. For example, a different type of coater may be used to coat the curable silicone composition on the substrate. Alternatively, more than one coater may be used in series, for example, when the thickness of the gel layer 102 is greater than 1.5 mm.
Methods of Use
[0114] The form stable gel described above may be used to provide a seal between a first substrate and a second substrate. The method for using the form stable gel comprises i) applying the form stable gel described above to a first substrate, and ii) connecting the first substrate and a second substrate with the form stable gel between the substrates. The method may optionally further comprise iii) shaping the form stable gel to conform to the substrates, e.g., by trimming the form stable gel after step ii), or by die cutting the form stable gel before step i).
[0115] The substrates may be any substrates commonly used in the construction industry, such as wood, metal (e.g., aluminum or steel), glass, fiberglass, plastic (e.g., extruded polyvinylchloride), or combinations thereof. For example, in one application, the form stable gel may be used to provide a seal that prevents moisture from entering two members of a window frame. The first substrate may be a frame member, such as an aluminum mullion, and the second substrate may be a second aluminum fame member. The mullion may be fastened to the frame member with fasteners such screws or bolts. The form stable gel forms a seal between the mullion and the frame member even after the fasteners pass through the gel.
[0116] A method for using the form stable gel is exemplified in FIGS. 3 and 4 . In FIG. 3 , an aluminum mullion 3 a with irregular shape and a strip of form stable gel 3 b are provided. The form stable gel 3 b is manually applied to the end of the aluminum mullion 3 c. The form stable gel adheres to the end of the mullion when it is moved 3 d. The aluminum mullion is fastened to an aluminum frame member with screws 3 e (front view), 3 f (back view). FIG. 4 shows the step of trimming the form stable gel. The excess form stable gel can be removed by manually cutting with a knife Alternatively, the form stable gel could be precut by a die cutter into the shape of the mullion for a more precise fit.
[0117] Alternatively, the form stable gel may be used for sealing in replacement window applications and retrofit window applications. For example, to install a replacement window, a method comprises i) removing the old window and ii) sliding a new window into the space left by the old window from the outside. The form stable gel may be applied to the wall around the space or to the frame around the new window before step ii). The method further comprises fastening the new window in place, for example, by installing screws from the inside.
[0118] Alternatively, the form stable gel may be used for sealing a bathroom or kitchen fixture to a mounting. At least one of the first substrate and the second substrate may be a fixture selected from the group consisting of a shower enclosure, bathtub, and a sink. For example, the form stable gel may be applied to a sink (e.g., kitchen or bathroom sink), and the sink may then be mounted to a cabinet.
[0119] Alternatively, the form stable gel may be used for sealing applications in boats. One of the first substrate and the second substrate may be a boat hull. The other of the first substrate and the second substrate may be boat window or a pipe, such a septic tank line.
EXAMPLES
[0120] The following examples are included to demonstrate the invention to those of ordinary skill in the art. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention set forth in the claims. All amounts, ratios, and percentages are by weight unless otherwise indicated.
[0121] The following ingredients were used in the examples.
[0122] Base Polymer (A1) was dimethylvinylsiloxy-terminated polydimethylsiloxane having a viscosity of 5,000 mPa·s (using a Brookfield RVT CP-52 viscometer at 5 rpm) and a vinyl content ranging from 0.15% to 0.19% (measured using infra red techniques).
[0123] Crosslinker (B1) was a trimethylsiloxy-terminated poly(dimethylsiloxane/methylhydrogensiloxane) polymer having a viscosity ranging from 141 cSt to 172 cSt using the standard capillary method, SiH content ranging from 0.112% to 0.118% using Infra red techniques.
[0124] Catalyst (C1) was a mixture of 5.5% of 1,3-diethenyl-1,1,3,3-tetramethyldisiloxane complex of platinum in a dimethylvinylsiloxy-terminated polydimethylsiloxane, having a viscosity ranging from 300 to 700 cP (300 to 700 mPa·s) and an amount of platinum metal ranging from 2.2% to 2.4%.
[0125] Chain Extender (1) was a hydrogen terminated polydimethylsiloxane having a viscosity ranging from 9 to 13 cSt using the standard capillary method and SiH content ranging from 0.112% to 0.119% using Infra red techniques.
[0126] Stabilizer (1) was 3,5-dimethyl-1-hexyn-3-ol, commercially available from Sigma-Aldrich of Milwaukee, Wis., 53201, USA.
[0127] Calcium Carbonate (D1) was Hubercarb Q from Huber Engineered Materials, part of J. M. Huber Corporation, of Quincy, Ill., 62305-9378, USA. This ground calcium carbonate was treated with 0.75% to 1.5% stearic acid.
Example 1
[0128] A two part curable silicone composition was prepared. First, the Calcium Carbonate (D1) was dried by heating for 4 hours in an oven at 150° C. The base was prepared by mixing 9 weight parts Base Polymer (A1) and 0.008 weight parts Catalyst (C1) in a 5 gallon (18.925 litre) pail for 5 minutes. Calcium Carbonate (D1) in an amount of 11 weight parts was added and mixed for 5 minutes or until smooth.
[0129] The curing agent was prepared by mixing 8.25 weight parts Base Polymer (A1), 0.24 weight parts Crosslinker (B1), 0.5 weight parts Chain Extender (1) and 0.008 weight parts Stabilizer (1) in a 5 gallon (18.925 litre) pail for 3 minutes. Calcium Carbonate (D1) in an amount of 11 weight parts was added and mixed for 5 minutes or until smooth.
[0130] The base and curing agent were combined and the resulting curable silicone composition was applied to opposing sides of a fiberglass mesh (1084/A57C), which is available from BGF Industries, Inc. of Greensboro, N.C., USA). The curable silicone composition was cured by heating at 125° C. for 30 minutes. The apparatus in FIG. 2 was used to prepare the form stable gel in this example.
[0131] The fiberglass payoff 201 operated with a centered spindle position and a payoff tension of 0 to 15 psi (0 to 1.05 kgcm −2 ). The fiberglass 209 roll length was 1000 m, and the weight was 55 kg. The primary coater 202 and primary heater 210 operated at a startup temperature ranging from 240° F. to 260° F. (115.56 to 126.67° C.) and a run temperature ranging from 260° F. to 360° F. (126.67 to 182.2° C.). The drive speed was 1 to 8 feet per minute (fpm) (0.305 to 2.44 metres per minute), and the thickness of the curable silicone composition applied to the fiberglass was controlled by the blade gap of the coater blade from the fiberglass. The secondary coater 211 and secondary heater 212 operated at a startup temperature ranging from 260° F. to 280° F. (126.67 to 137.8° C.) and a run temperature ranging from 260° F. to 360° F. (126.67 to 342.2° C.). The drive speed was 1 to 8 fpm (0.305 to 2.44 metres per minute). The thickness was controlled by the roll gap.
[0132] The product take up 214 was operated with a centered spindle position. The take up tension ranged from 20 to 40 psi (1.4 to 2.8 kgcm −2 ) and the pay off tension ranged from 5 to 15 psi (0.35 to 1.05 kgcm −2 ). The form stable gel product roll weight ranged from 25 to 35 kg and its length varied.
Example 2
Performance
[0133] A sample of the form stable gel prepared in example 1 was placed against a vertical aluminum frame member. A horizontal aluminum frame member was fastened to the vertical aluminum frame member with screws. The vertical aluminum frame member was hollow and filled with 18 inches (45.72 cm) of water. The frame had no visible leaks after 3 months, which exceeded the industry standard measurement of 3 inches (7.62 cm) of water with no leaks after 18 minutes.
Reference Example 1
Tack Measurement
[0134] A strip of form stable gel with dimensions of 1 inches by 6 inches (15.24 cm) was prepared using the coating apparatus in FIG. 2 . The strip was placed between plastic plates with holes through the centers, thereby exposing a 1 inch (2.54 cm) diameter stretched membrane of form stable gel secured at its edges. A TA-XT2 Texture Analyzer was used to measure tack. The probe was descended onto the gel and depressed 2 mm at a speed of 0.2 mm/sec, and tack was recorded by measuring the force to lift the probe off the gel.
Reference Example 2
Hardness Measurement
[0135] Gel samples (9 mL) were prepared by mixing equal weights of base and curing agent, subjecting the mixture to vacuum for 2 to 5 minutes or until bubbles disappeared, cured in an oven at 125° C. for 30 minutes, and then cooled for 10 minutes.
[0136] A Texture analyzer with a ¼ inch (0.635 cm) steel ball probe attached thereto was used for the test. The ball probe was cleaned with isopropanol and wiped with a kimwipe. The hardness was measured by indentation of the sample with the ball probe. The probe indentation distance was 0.4 mm at a speed of 0.2 mm/s.
INDUSTRIAL APPLICABILITY
[0137] The form stable gel described herein combines two effects to create a seal. First, under compression gels can conform around a variety of objects or irregular surfaces, so that the gel is in contact with the entire surface of the object to be sealed. Once the surfaces of the objects are in contact, the system dynamics may favor the coating of the surface by the gel versus by gas such as air or liquid or vapor such as water. This combination of conformability and surface wetting by the gel allows the form stable gel to seal against air and water. For purposes of this application, sealing against water means that a seal prepared with the form stable gel described herein passes the water penetration test of ASTM Standard E331. The form stable gel is self supporting enough and self adhesive enough to remain in place during assembly of a frame (or other substrates). The form stable gel does not leave residue when trimmed, as a conventional foam tape can. The form stable gel is therefore useful in a variety of applications in the construction industry.
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A form stable gel may be used to make a seal between substrates to minimize air and moisture penetration. The form stable gel is useful in construction industry applications such as sealing window frame members, sealing retrofit and replacement windows, as well as indoor applications such as sealing bathtubs, sinks and shower surrounds. The form stable gel is also useful for sealing applications in boat hulls.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a U.S. national stage application filed under 35 U.S.C. §371 of International Patent Application PCT/AU2009/000729, accorded an international filing date of Jun. 11, 2009, which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to an Energy and Emission Management (“E2M”) system and methods for reducing the costs of energy consumption and greenhouse gas emissions for Intensive Energy Consuming Systems and Sites (“IECSS”) found in areas such as manufacturing, industrial and resources sector.
BACKGROUND TO THE INVENTION
[0003] The manufacturing, industrial and resources sector contribute a large volume of greenhouse gas emissions through their intensive use of energy for production processes. Energy expenditure by the sector is often one of the largest single cost items, and with dwindling natural resources of coal, oil and gas the price for energy is continually escalating. The collective various government and non-government organisations throughout the world are starting to understand the cost to the global community of Climate Change caused by Greenhouse Gas (“GHG”) emissions.
[0004] Some governments have introduced measures to ensure that consumers who use polluting energy (ie. Electricity from fossil fuel, diesel from oil) are economically disadvantaged to those who use renewable or lower emission energy (ie Renewable Electricity, biodiesel). One form of these consist of Emissions Trading Mechanisms, and are continuing to be implemented, placing a price on the greenhouse emissions created by the energy consumer.
[0005] The traditional cost of energy expenditure by the Industrial sector now can also have a mutual, but exclusive cost of GHG emission to be considered and managed. Energy efficiency or predictive methods for making prediction on energy consumption alone may not be not enough to maximize cost savings.
[0006] Typical systems and methods have been based on the singular (energy consumption) alone. An example can be found in United States Patent Application Publication No 2003/0061091 to Amaratunga et al, and see U.S. patent application Ser. No. 11/613,728 to MacGregor, the contents of which are hereby incorporated by cross reference.
[0007] Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.
SUMMARY OF THE INVENTION
[0008] In accordance with a first aspect of the present invention, there is provided a method of performing energy estimations operations in an intensive energy consuming site or system environment, the method comprising the steps of: (a) inputting a series of energy, emission and influencing data variables related to the intensive energy consuming site or system environment; (b) performing a first energy use prediction operation utilising a first prediction technique; (c) performing a second (simultaneous) similar energy use prediction operation utilising a second prediction technique; (d) correlating the results of the two techniques and; (e) providing a pass or fail signal depending on the level of correlation between the two techniques.
[0009] The prediction techniques can include one of at least Regression and Artificial Neural Network techniques. The method can be performed to determine the environments efficiency or to predict or forecast the future energy needs and/or related emissions of the environment. The method can also further include the steps of: performing at least one further energy use prediction operation utilising a further different prediction technique; and providing a further output signal indicative of the level of correlation between all the energy use prediction operations.
[0010] In accordance with a further aspect of the present invention there is provided a system for performing energy estimations operations in an intensive energy consuming site or system environment, the system including: input means for sensing and inputting a series of data variables relating to energy or emissions from the site or system environment; data storage means for storing time series data from the input means; first prediction unit trained from data stored in the data storage means utilising a first prediction technique to output a first prediction; second prediction unit trained from data stored in the data storage means utilising a second different prediction technique to output a second prediction; and comparison means for comparing the first and second prediction and outputting a measure of the difference there between.
BRIEF DESCRIPTION OF THE PREFERRED AND OTHER EMBODIMENTS
[0011] Preferred forms of the present invention will now be described with reference to the accompanying drawings in which:
[0012] FIG. 1 illustrates schematically a simplified block diagram of the preferred embodiment of the invention representing the system for Energy and Emission Management (E2M)
[0013] FIG. 2 illustrates the energy prediction system of FIG. 1 in more detail.
DESCRIPTION OF PREFERRED EMBODIMENT
[0014] The preferred embodiment provides a predictive system and method of management that integrates Energy Consumption and Greenhouse-gas Emissions (ECGE) business intelligence into an overall strategy for managing the energy and greenhouse emissions of the IECSS. The system ideally compares Real-time (or near Real Time) ECGE with the hypothetical target values obtained from the predictive systems so deviances from optimal cost performance can be constrained through actions, such as maintenance, behavioural change, training of personnel or rescheduling of production.
[0015] The ability to predict energy consumption has a number of beneficial side effects. It allows energy waste to be minimised, efficiency to be identified for retention and energy supplies to be selected at the lowest cost and with the lowest GHG emission content. Sophisticated statistics in the form of regression analysis provide predictive systems and methods as tools for energy management. The systems and method of prediction in the aforementioned patent specification use this method. Alternatively, other techniques such as modelling prediction involving Artificial Neural Networks can be used. For example, U.S. patent application Ser. No. 11/613,728 to MacGregor discloses such a system.
[0016] Regression and Artificial Neural Networks are two very different forms of statistical analysis, and arrive at their prediction using different processes. Regression estimates the weights to apply to a single equation, whereas the Artificial Neural Network approach uses a system of equations represented by a series of interconnected switches. A single input in an Artificial Neural Network can influence multiple intermediate switches that in turn influence the final prediction, often making it difficult to find how an individual input is affecting the predicted outcome. If the single input influence is unknown, then the precision of the neural weighting scheme is unknown. On the other hand, Regression specifies how much each input impacts the prediction, and how accurately it was able to estimate the impact.
[0017] While the Artificial Neural Network technique can yield more powerful predictions, it does a poorer job of explaining why it is working or how much confidence it has in the prediction. Present methods and systems of energy management for energy and cost efficiency using predictive statistics use either Regression or Artificial Neural Network statistics. Regression gives outputs which the energy management system or method can use to investigate efficiency improvements, whereas Artificial Neural Networks provide less information for anomaly investigation for efficiency improvements. Artificial Neural Networks can provide greater forecast prediction capabilities than Regression, but have no support to verify the confidence of the predictions for (say) optimisation hypothesis tests, demand management, energy market trading and/or emission trading.
[0018] In the preferred embodiments, there is provided a predictive method and system for running Regression and Artificial Neural Networks (and any suitable other statistical methods such as Support Vector Machines) simultaneously on the same datasets to enable cross-verification of predictions appropriate to the task. In particular, simultaneously use of Regression for energy-consuming optimisation applications with Artificial Neural Networks (and others) as the validation check, and using Artificial Neural Networks for forecast prediction applications with Regression (and others) as the validation check. This may be provided continuously or at regular periodic intervals for ongoing predictions.
[0019] The preferred embodiments provide an Energy and Emission Management (“E2M”) system and methods for reducing the costs of Energy Consumption and Greenhouse-gas Emissions (“ECGE”) for Intensive Energy Consuming Systems and Sites (“IECSS”) found in the manufacturing, industrial and resources sector using simultaneous prediction algorithms of (at least) Regression and Artificial Neural Networks to cross-verify the prediction outputs. The term ‘Simultaneous’ includes existing, occurring and operating at the same time, or within the shortest time-sequence practical to achieve near-synchronism.
[0020] The preferred embodiments include a means for measuring the ECGE of the IECSS, means for determining information regarding the operation of the IECSS, means for measuring or obtaining variables that may influence the rate of ECGE of the IECSS, means for transmitting measurement and operational information about the IECSS to a means for receiving the information, means for analysing and evaluating the information, means for deriving energy efficiency algorithms and models for base-line benchmark, expected or predicted amounts of ECGE by the IECSS, means for cross-checking the confidence interval for verification of the base-line, expected or predicted amounts of ECGE by the IECSS, and means for providing access to the base-line, expected or predicted values of ECGE for the purpose of ECGE management activities, and a means for measuring and validating the results of the ECGE management activities.
[0021] Turning initially to FIG. 1 there is shown schematically an Energy and Emission Management (hereinafter called “E2M”) system 1 for Intensive Energy Consuming Systems and Sites (hereinafter called “IECSS”) normally found in the manufacturing, industrial and resources sector. The term “Energy” means all forms of energy and fuel that are consumed to operate the IECSS, and include, but are not limited to electricity, natural gas, flammable gas, diesel, gasoline, oil-derived fuels, biofuels, biomass, sulphur, and coal. The term “Emission” means greenhouse gas air emission from the direct or in-direct use of Energy and may include SO 2 , NO and CO 2 . The term “Intensive” means those manufacturing, industrial or resource sector systems or sites that consume, for example, a minimum equivalent of 20,000 MWh or 80,000 GJ of energy per annum of operation. Examples of IECSS include: manufacturing sector (brick and tile factories, ceramic factories, automotive factories), industrial sector (paper and wood pulp production, chemical production, steel/metal foundry and production, specialist gas production, cement production, aluminium smeltering), resources sector (mineral processing plants, petrochemical refineries, gold/copper/nickel/iron ore mines and processing plants).
[0022] The E2M system continuously monitors the IECSS by collecting data from E2M monitoring devices e.g. 2, 3 which can include energy metering, energy sub-metering, emission monitoring and energy-influencing variables directly from field instrumentation and control devices at the IECSS using communications devices to transfer data from the IECSS to the remote data centre for manipulation. The monitoring device data is stored in a database 5 . The data is then used by prediction system 6 for predicting energy usage. The E2M Monitoring Devices e.g. 2, 3 can include measurement systems and tools to measure, analyse, evaluate, predict and cross-check amounts of Energy Consumed and Greenhouse-gas Emissions (hereinafter call “ECGE”) by the IECSS and associated methods and use of such measurement systems and tools.
[0023] The E2M system 1 continuously compares actual ECGE against a predicted ECGE and analyses variances for identifying opportunities to improve energy efficiency and reduce greenhouse emission for the purpose of saving costs.
[0024] The preferred embodiments use simultaneous prediction algorithms of (at least) Regression and Artificial Neural Networks to cross-verify the predictions. In particular, the preferred embodiments are related to continuously improving the productivity-related use and supply of energy, while minimising the respective direct and indirect greenhouse gas emissions for cost savings and environmental sustainability. In the preferred embodiment, there is provided a method and apparatus for producing a more accurate estimate of both current site efficiency and predictions or forecasts of future requirements.
[0025] Turning now to FIG. 2 there is illustrated the Energy Prediction System in more detail. The database inputs are forwarded to a Regression prediction system 7 and an Artificial Neural Network prediction system 8 , each of which output a prediction based on the input data. The preferred embodiment utilizes at least two models to produce estimates of likely outcomes. In a first embodiment, there is provided a first Artificial Neural Network model for estimating likely outcome and a second Regression model of estimating a likely outcome. The first model can be based around a similar architecture to that disclosed by Macgregor (with the exception of input data derived as described in Amaratunga et al) and the second Regression model can be similar to that based around Amaratunga et al.
[0026] In the preferred embodiment these two (or more) models receive the relevant inputs from the environment of the specific IECSS and simultaneously output estimations of energy requirements. The method of the preferred embodiment then goes through an important step of cross correlating the outputs for prediction verification.
[0027] Where a measure of site efficiency is required, the Regression process is utilized as the primary prediction and the Artificial Neural Network model is provided as the verification prediction. Where divergence between the two models is beyond a predetermined limit, the prediction output 10 is flagged as inadequate for the particular data sample. Examples of divergence may be caused by IECSS system upsets or erroneous data inputs due to system malfunction or calibration
[0028] Where a further-into-the-future prediction or forecast is required, the Artificial Neural Network model output is utilized for the primary prediction. The Regression model output is utilized as the verification prediction. Where the divergence between the two models is beyond a predetermined limit, the prediction output is again flagged as inadequate.
[0029] It has been found that utilizing multiple models simultaneously and cross checking there between provides for a substantially more accurate prediction network than that provided by the prior art.
EXAMPLES
[0030] One example of the E2M in operation may indicate that the overall IECSS energy efficiency is higher when workers from ‘Shift A’ are operating the IECSS instead of ‘Shift B’. The action would be to interview and observe the differences between the two groups of workers, then assume a ‘best operating practice’ from the ‘Shift A’ habit. Another example of E2M may indicate where energy is wasted through underutilisation of equipment during production, such as conveyors still running when upstream equipment has faulted, has stopped for maintenance or not producing. The action would be to interlock with the controls of up-stream equipment to minimise downstream equipment run-times. Another example of E2M may indicate higher than expected actual natural gas consumptions and emissions of a boiler during periods of high ambient temperature. An action would be to inspect for thermal insulation failures, and check the calibration and operational efficiency of the gas burner. Another example of E2M may indicate that cement raw materials from Supplier 1 tend to be processed more efficiently into a cement product than materials from Supplier 2 , and create fewer emissions. One action would be to undertake a laboratory analysis of raw material samples to identify the differences in raw material supply, then create a ‘Quality Specification’ of best practice supply for all Suppliers to meet. Another example of E2M may indicate that the size of ‘run-of-mine’ ore into a gold processing crushing plant influences the energy consumed throughout the process. An action would be to undertake a study using the E2M system archived data to determine the optimum fragment size of ore for energy-efficiency for crushing and grinding, then optimising a blast pattern for ore supply to the gold processing and recovery plant.
[0031] The expected or predicted ECGE of the IECSS can be outputs of (at least) two simultaneous but independent transfer functions developed from an initial period (days, weeks or years) of data sampling (hereinafter called “E2M Baseline”) from the IECSS; one transfer function is derived from regression-based statistics and the other derived from artificial neural network-based statistics. The two methods are used simultaneously to provide prediction verification and to facilitate energy efficiency improvement investigations. In alternative embodiments, further (n) statistical methods may be added for simultaneous concurrence of results.
[0032] Embodiments can include the periodic volumetric summation of the actual energy-related direct and indirect greenhouse gas emission deviation from the E2M Baseline to verify greenhouse gas emissions offset by energy efficiency of the IECSS. For example, a monthly emission offset calculation consisting using: CO 2 Offset=[Σ 0 n actual electricity kWh consumed−Σ 0 n E2M Baseline_predicted electricity kWh consumed]*[internationally recognised greenhouse gas emission calculation factors]
[0033] Embodiments can also include the periodic substitution of time-series forecast IECSS information (such as production plan, staff roster plan, maintenance plan, raw material delivery schedules, energy trading futures pricing, gas supply upstream heating quality data, electricity supplier planned outages, biomass harvesting schedules, fuel delivery schedule) and/or meteorological data (such as weather forecast of wind, humidity, precipitation, solar or UV Index, tidal, wave, swell, water management plans) into the rolling time-series forecast model (hereinafter referred to as the “E2M Forecast”) to predict the future ECGE of the IECSS for integration into the overall energy and emission trading strategy of the IECSS.
EXAMPLES
[0034] As an example, the IECSS is taken to be a brick-making facility using a natural gas-fired kiln. The production plan may indicate a 36 hour production run at the full capacity of two production lines, while the forecast meteorological conditions indicate above-average daily ambient temperature conditions for the period. The electricity supply market indicates higher on-peak day-time costs during high temperature days. The operator shift pattern indicates more experienced production staff available through the night-shift. The IECSS has a small combined-heat and power (CHP) generation station. An analytical strategy developed from the E2M system and method would indicate to run production for half capacity (run only one production line) for twelve hours (day-shift), followed by full capacity (both production lines) for twelve hours (night shift). Surplus gas-supply (from running at half capacity) can be diverted to the CHP, where electricity is supplied to the IECSS at a lower cost than the peak market rates, while delivering exhaust heat to the brick-drying section (reducing gas consumption further). During the following twelve hours (night shift) the CHP would be turned off to take advantage of low off-peak electricity prices, and to ensure full natural gas supply is delivered for full production rate. The net result is lower costs from electricity, and lower greenhouse gas emission from on-site CHP generation.
Analysis of the Method
[0035] The Energy Prediction System determines correlation of ECGE to influencing variables of the IECSS to produce base-line benchmark models. The resultant output consists of identifying real-time or near-real-time anomalies in ECGE using cross-verified prediction methods, and arranging optimising investigations. The outputs can also include predicting the future ECGE using cross-verified prediction methods for incorporation into the IECSS energy and emission trading strategy. This can lead to determining permanent optimisation improvements and provide a means of identifying the related ECGE costs saved while also providing evidence for Energy Efficiency-based emission trading credits. The method can continuously cycle for continuous improvement.
[0036] The FIRST step in the preferred embodiment of the invention, involves using the customisation criteria to: determine, identify and record the number and type of ECGE information gathering nodes, determine, configure, test and install the required number of E2M Monitoring Devices, determine the components, configure, program the parameters, test and install the E2M Monitoring device, determine the file and database structure, archiving convention, configuration, testing and installation of IECSS data transmitting/receiving, archiving, database, statistics and web portal software.
[0037] As noted previously, the Regression and Artificial Neural Network prediction systems can be formulated via transfer functions developed from an initial period of data sampling and are called the “Baseline Algorithms BL-i”. Each transfer function will be a mathematical model that continuously relates the periodically sampled amounts of a particular form of energy consumption and/or the related greenhouse emissions to the characteristic operating factors (influencing factors) within the specific operating environment of the IECSS. The influencing factors within the specific operating environment of the IECSS may include, but are not limited to, production rate, types of product made, raw material quantities and characteristics, operating staff identification, ambient and process temperatures, ambient and process relative humidity's, solar radiation levels, pressures, ancillary equipment operating patterns (compressed air, boiler, air conditioning), sub-metering energy counters, gas monitoring equipment, mass flow metering, flue-gas analysers etc.
[0038] The analysis of the variance between the predicted and actual amounts of specific ECGE can graphically reproduced and periodically updated automatically to tables and charts that clearly show energy and emission reduction opportunities to an E2M manager. This analysis information is comprised of, but is not limited to, a summary of ECGE with regards to variances from the predicted or expected amounts, for example an analysis that includes at least one of summaries, graphs, charts and quantification of energy use and related emissions versus predicted or expected amounts, and that of variables that influence energy use and related emissions.
[0039] As noted previously, where site efficiency is an issue, the (linear and/or non-linear) Regression statistics will present the ‘Priority Prediction’ while the simultaneous trained Artificial Neural Network (hereinafter named “ANN”) model will provide a ‘Verification Prediction’ to cross-match the transfer function outputs for acceptable Pass/Fail indication. In alternative embodiments, further (n) statistical methods may be added for simultaneous concurrence of results.
[0040] The ‘Priority Prediction’ will provide the diagnostic information on the variances to present the likely causes therefore. The E2M manager can use this diagnostic to investigate further at the IECSS using a ‘Six-Sigma’, ‘LEAN’ or other business improvement investigation method. Investigation outcomes will result in recommendations to the staff at the IECSS, such as a maintenance action or rescheduling of production, to reduce ECGE while improving productivity. This is an ongoing process.
[0041] Each time energy efficiency improvements are implemented at the IECSS, new Baseline Algorithms are developed. Reduced ECGE as a result of improved energy efficiency is quantified as a difference between the old and new baseline algorithms when substituting actual influencing data into both.
[0042] Further to energy and emission reduction opportunities, the E2M may apply forecast predictions on the ECGE of an IECSS. Substituting meteorological forecast information (such as ambient temperature, solar intensity, and relative humidity), production schedule information, maintenance activity planning information, staff roster information, and historical time-series data from the IECSS into the prediction algorithms will generate a forecast total energy use profile, along with associated greenhouse gas emission forecast. In this instance, the trained Artificial Neural Network (hereinafter named “ANN”) model can present the ‘Priority Prediction’ while the simultaneous (linear and/or non-linear) Regression statistics will provide a ‘Verification Prediction’ to cross-match the transfer function outputs for acceptable Pass/Fail indication. In alternative embodiments, further (n) statistical methods may be added for simultaneous concurrence of results.
[0043] Although the invention has been described with reference to specific examples it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.
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A method of performing energy estimations operations in an intensive energy consuming site or system environment, the method comprising the steps of: (a) inputting a series of energy, emission and influencing data variables related to the intensive energy consuming site or system environment; (b) performing a first energy use prediction operation utilising a first prediction technique; (c) performing a second (simultaneous) similar energy use prediction operation utilising a second prediction technique; (d) correlating the results of the two techniques and; (e) providing a pass or fail signal depending on the level of correlation between the two techniques.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. application Ser. No. 221,640 and U.S. application Ser. No. 221,639, both filed Dec. 31, 1980, both now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to blood gas calibration and control fluids and, more particularly, fluids containing hemoglobin.
2. Description of the Prior Art
Blood gas tests are frequently used in health care facilities to determine abnormalities in pulmonary function. These parameters commonly used in determining pulmonary abnormalities are blood pH, P CO .sbsb.2 and P O .sbsb.2. The tests are performed by drawing blood from the patient and introducing this blood into specialized equipment which determines the various parameters to be measured. The specialized equipment must be calibrated frequently to determine if the readouts on values for patient blood are accurate. This calibration involves introducing various solutions or gases having predetermined amounts of constituents which are present in in vivo blood.
After the testing equipment has been calibrated it is necessary to assure maintenance of the calibration routine. For this reason the instrument is frequently tested with blood gas controls which quickly and readily determine any unexpected analytical deviations. The blood gas controls do not have absolute values for pH, P CO .sbsb.2 and P O .sbsb.2. Instead ranges are provided; if the instrument responds within the specified range, the accuracy of the calibration is assured.
Typical blood gas control techniques and solutions are taught in U.S. Pat. No. 3,859,049; Clin. Chem. 24, p. 793-795, 1978 by Steiner et al.; U.S. Pat. No. 3,973,913; and U.S. Pat. No. 4,001,142.
In calibrating or controlling of the instrumentation for blood gas analysis, it is desirable to use a material containing the predetermined amount of blood constituents which most approximates the function of blood to obtain accurate readings. Thus, the ideal solution would be blood having predetermined amounts of constituents to calibrate the instrumentation. However, use of blood as a calibration or control fluid is impractical because of instability and degradation problems upon aging, and the generation of methemoglobin on aging which destroys the oxygen carrying function of the hemoglobin constituents. Furthermore, with whole blood it is difficult if not impossible to adjust the pH accurately and reproducibly.
Thus, several other types of solutions have been proposed and used as blood gas calibration standards or controls. The most widely used are aqueous solutions such as taught in U.S. Pat. No. 4,001,142. These solutions have several problems associated with their use. Aqueous controls have excellent shelf life. However, once the seal is broken the aqueous control must be used immediately since when the aqueous control solution is open to the environment, there is rapid exchange of the dissolved gases and the control fluid with the external environment thereby changing the concentration of the assayed constituents. Such exchanges result in inaccurate recovery of the assayed parameters.
In addition, a small amount of liquid which has been exposed to, and therefore, equilibrated with the atmosphere, or other gas is present in the instrument sample chamber. The gas permeable membranes separating the electrode from the chamber also may contain trapped gas. This residue can mix with the sample and cause changes in the gaseous constituents, especially oxygen. With whole blood these changes are effectively negated, due to the reversible interaction of hemoglobin and oxygen which provides a high "oxygen buffer capacity". Typical aqueous blood gas controls contain no such "oxygen buffer capacity" and are, therefore, easily contaminated during sample handling and within the sample chamber.
The values obtained for the assayed constituents in whole blood (pH, P CO .sbsb.2 and P O .sbsb.2) are dramatically affected by the temperature of the sample chamber in which the sample is being analyzed. The control material must, therefore, respond to temperature changes in the instrument similar to whole blood. No typical aqueous blood gas control responds appropriately to temperature induced value changes in all measured parameters. The control material of the present invention containing stroma-free hemoglobin closely simulates the response of whole blood with respect to all measured parameters.
To avoid some of these problems treated red cells in a buffer have been used as a blood gas control. Louderback U.S. Pat. No. 3,973,913 teaches such a blood control standard in which the cells are treated with aldehyde to render the cell membrane less sensitive to lysing and inhibit the metabolism of the cell. The stability of the control when opened is improved but the shelf life is significantly decreased. However, the treatment effects the hemoglobin so that it is apparently no longer physiological. In order to provide an effective oxygen buffer system, the hemoglobin contained in the control must be in such a form that its oxygen affinity is similar to that of whole blood. The controls containing treated erythrocytes contain hemoglobin that has an enhanced oxygen affinity and, therefore, suffer from a reduced oxygen buffer capacity.
A quality control material for blood gas analysis must also be convenient to use and thus minimize pre-analytical variables. If it is extremely difficult to prepare the ampulized sample for analysis, then the potential for error increases. Controls containing treated red cells must be carefully re-equilibrated at 37° C. In addition, the treated red cell controls may only be kept re-equilibrated for 30 minutes before discarding.
Thus, it is desirable to use a calibration solution which functions as nearly as possible to blood while eliminating the problems associated with the use of blood as a blood gas control or calibration fluid. In accordance with the present invention, a blood gas control fluid is provided which approximates the function and the gas carrying ability of human blood without the stability problems associated with blood. Like whole blood, the blood gas reference fluid of the present invention incorporates hemoglobin as a reversible oxygen buffer system thus minimizing any errors due to contamination during handling and analysis. The stroma-free hemoglobin has near normal oxygen affinity. The control fluid re-equilibrates at normal room temperature and may be re-equilibrated for up to 48 hours before assay without deleterious effects.
A further advantage of the present invention is the deep red color of the hemoglobin which allows easy visualization within the sample chamber of the analyzer. Like whole blood, this property readily shows the presence of any trapped air bubbles accidently introduced into the measuring chamber.
BRIEF DESCRIPTION OF THE INVENTION
A reference fluid for the calibration and control of blood gas instruments is comprised of substantially pure stroma-free hemoglobin solution, a source of bicarbonate ion, a buffering agent and predetermined amounts of gases present in in vivo blood and specifically oxygen and carbon dioxide.
The stroma-free hemoglobin provides an effective oxygen buffer system. Its oxygen affinity is nearly the same as whole blood and, in fact, simulates the response of whole blood with respect to all measured parameters.
A source of bicarbonate ion is necessary to control the CO 2 content and may be used as a buffer to adjust the pH of the reference fluid. Sodium carbonate is an excellent source of bicarbonate ion and may be present in amounts up to 75 millimoles/liter of solution. A phosphate buffer such as Na 2 HPO 4 is also desirable. An electrolyte source such as sodium chloride, potassium chloride, calcium chloride, etc. may be added. It should be noted that all the additions are physiological; they are present in normal blood.
A broad spectrum antibiotic such as gentamicin or penicillin may also be added to assist in processing by controlling unwanted microbial growth during the processing.
Finally, predetermined amounts of the gases normally present in in vivo blood, generally O 2 and CO 2 , and an inert gas such as N 2 are present. A typical blood gas control is prepared at three levels to simulate the clinically significant acid base respiratory balance and function. The P O .sbsb.2 will range from 10 to 500 mm. Hg at 37° C. The P CO .sbsb.2 will range from 5 to 100 mm. Hg at 37° C. The pH will range from 6.8 to 8.0 at 37° C.
DETAILED DESCRIPTION OF THE INVENTION
The fluid utilized in the blood gas control is an aqueous solution of substantially pure stroma-free hemoglobin. "Substantially pure" as used herein means and refers to the hemoglobin being free of proteins, lipoproteins, enzymes and other blood constituents which tend to degrade the hemoglobin.
The preparation of stroma-free hemoglobin is known in the art. For example, suitable stroma-free hemoglobin may be prepared by the process disclosed in "An Improved Stroma-Free Hemoglobin Solution" by Greenberg et al.; Surgical Forum V. 26, pp. 53-55 (1975); "Further Studies with Stroma-Free Hemoglobin Solution" by Rabiner et al.; Annals of Surgery, pp. 615-622 (April 1970); "Accute Oxygen Supply by Infusion of Hemoglobin Solutions" by Bonhard; Federation Proceedings V. 34, No. 6, pp. 1466-1467 (May 1975); "Blood Substitute and Blood Plasma Expander Comprising Polyhemoglobin" by Bonsen et al., U.S. Pat. No. 4,001,401; and "Characteristics of Stroma-Free Hemoglobin Prepared by Crystallization" by DeVenuto et al.; J. Lab. Clin. Med., pp. 509-516 (March 1977). Broadly speaking, washed red cells are lysed, the stroma precipitated and the supernatant containing the stroma-free hemoglobin separated from the precipitate by centrifugation. The stroma-free hemoglobin should be sterile filtered.
A particularly useful method of preparing stroma-free hemoglobin is taught in U.S. patent application Ser. No. 290,175, entitled "Process For The Preparation Of Stroma-Free Hemoglobin Solutions" of Simmonds et al., filed the same day as this application. Said patent application is incorporated herein by reference and made a part hereof.
The substantially pure stroma-free hemoglobin solution is adjusted in order to provide a hemoglobin solution of 1 to 30 percent hemoglobin and preferably about 6 to 18 percent hemoglobin. During the adjustment it is desirable to add nongaseous constituents of the blood gas control. This may be accomplished by direct addition of solid materials, as concentrates or in a diluent solution.
In one method of calculation of diluent required, the following equations are used to determine the quantity of such diluent: ((hemoglobin concentration) (volume of hemoglobin solution))/desired percentage of hemoglobin solution=final volume of hemoglobin solution at the desired percentage; and (volume at desired percentage)-(present volume)=quantity of diluent required.
Diluents can be prepared which include various concentrations of the desired constituents. For example, where Na 2 HPO 4 (in the form of Na 2 HPO 4 .12H 2 O), sodium chloride, and an antibiotic such as gentamicin or the like are used, the determination of addition can be calculated as follows: (desired molar concentration) (final volume) (358.1 g/M)=grams Na 2 HPO 4 .12H 2 O to be added.
In the case of sodium chloride, the calculation would be: (desired concentration of NaCl) (diluent volume) (58.5 g/M)=required amount of solid NaCl. For gentamicin sulfate the calculation would be: (milligrams antibiotic/liter) (final volume) (1/0.6)=grams of antibiotic required.
In preparing the diluent, the required ingredients are added to the appropriate quantity of sterile deionized water.
Na 2 CO 3 is then added as a buffer for pH control to the blood gas calibration solution. The experimental determination of the appropriate quantity of Na 2 CO 3 is done by obtaining small aliquots of the diluted hemoglobin solution to which varying amounts of sodium carbonate are added. The aliquots are then tonometered at 25° C. with the appropriate gas mixture (preferably O 2 and CO 2 ). The pH of the tonometered solutions are determined by analysis on a blood gas analyzer and additional aliquots are prepared to achieve the desired pH. Preferably the gas mixtures range from up to 50% O 2 and up to 20% CO 2 . After the pH is tested and it is outside the desired range of pH (the preferable pH is 7.1 to 7.6), additional Na 2 CO 3 or additional hemoglobin solution may be added to obtain the correct pH. Once the correct amount of Na 2 CO 3 to be added to the diluent is determined, Na 2 CO 3 in the proper amount is added with mixing.
After the bulk diluent has been prepared, it is added to the hemoglobin slowly with constant stirring. The hemoglobin solution diluted to the desired level of in vivo blood gas constituents is then sterile filtered and stored between 2° and 8° C. The filtered hemoglobin solution is tested to assure absence of microorganisms. If growth is observed, the hemoglobin solution should be refiltered.
After the sterile hemoglobin solution has been obtained, it is warmed to 10° to 40° C. and equilibrated by use of a gas permeable membrane. A countercurrent of gas which has been warmed to the solution temperature and humidified to saturation is fed into the vessel to maintain an atmosphere over the solution of the same gas with which the solution is equilibrated. Samples are removed from the solution during equilibration and tested on a blood gas analyzer. Sodium carbonate solution may be introduced through a sterilizing filter during the equilibration the achieve the desired pH if necessary. The equilibration solutions will show stable values for pH, P O .sbsb.1 and P CO .sbsb.2. The bulk container for the blood gas reference fluid is purged with the gas used for equilibration. The equilibrated hemoglobin solution is then pumped through a sterile filter apparatus and filled into sterile, gas impermeable ampules or other suitable containers which have been preflushed with the equilibrated gas solution. The container is sealed under an atmosphere of the same gas.
The invention will be more fully illustrated by reference to the following examples.
EXAMPLE 1
Outdated human blood cells were charged to a 1 liter centrifuge bottle with an air space allowed thereover. Sterile wash solution consisting of 0.05 moles/liter of Na 2 HPO 4 and 0.22 moles/liter NaCl is charged at a temperature of 2° to 8° C. to the centrifuge bottles until full. The ratio of wash solution to cells was approximately 1:1. Several such bottles were prepared. The bottles were capped and the wash solution mixed with the blood by inversion. The bottles were placed in a centrifuge and centrifuged at 4,200 rpm (4,700×g) for 10 minutes. The centrifuge and rotor along with the centrifuge bottles were precooled to 5° C. to prevent methemoglobin formation.
After centrifugation, the supernatant wash solution was aspirated from the bottles. The bottles with the packed cells therein were filled with the same wash solution as above described and mixed by shaking and inversion. Centrifugation and aspiration of supernatant was repeated. The bottles with packed cells therein were filled with cold (2° to 8° C.) sterile 0.85 percent NaCl solution, mixed by inversion, centrifuged and aspirated as previously described. The ratio of sodium chloride solution to cells was 350 ml./unit of cells. The washed cells were poured into a funnel covered with layers of coarse and fine nylon mesh, the coarse nylon mesh having a mesh size of 120 microns and the fine nylon mesh having a mesh size of 40 microns. The nylon mesh retained the clumped white cells and other foreign matter which was present. The red cells were collected in a graduated cylinder in order to measure the amount of reagent required for stroma precipitation.
The pooled cells were disrupted by sonication using an ultrasonic probe equipped with a continuous flow cell. Cold water was passed through the jacket of the cell to avoid excess heating causing the formation of methemoglobin. The cells were pumped through the disruption cell at a speed of 300-350 ml./minute for a total of 5 passes. At the end of the 5 passes the residual cell count was less than or equal to 250,000/cu. mm. The cell lysate, forming a mixture of stroma and cytoplasmic components including hemoglobin, was collected and a 20% solution of calcium chloride was added with agitation thereto. The ratio of calcium chloride solution to cells was 50 ml. calcium chloride/liter of cells. After all of the calcium chloride had been added, the hemoglobin-stroma-calcium chloride admixture was mixed for 10 minutes. Five grams of dextran sulfate/liter of cells was added as a powder to the above admixture and mixed for 30 minutes. After 30 minutes, no undissolved material remained. 0.1 moles of Na 2 HPO 4 (in the form of Na 2 HPO 4 .12H 2 O)/liter of cells was added to the mixture and mixed for 30 minutes. Immediately after the addition of the Na 2 HPO 4 the total admixture was cooled to 2° to 8° C. and allowed to stand overnight (16 hours). The admixture was centrifuged at 4,000 rpm (4,700×g) for 90 minutes. Supernatant hemoglobin solution was collected and the complexed stroma and other lipoprotein constituents remained as the precipitant in the centrifuge bottles.
0.1 mole/liter of solid NaCl was added to the supernatant hemoglobin solution. The solution was passed through a Cuno CPX 90S filter cartridge followed by a Pall AR (0.2 micron). The filtrate was dialyzed by passing it through a series of C-DAK-2.5D artificial kidneys using a countercurrent flow of cold 0.1 molar NaCl solution. Subsequent to dialysis the solution was freed of microbial contamination by passage through a 0.2 micron filter and collected in a sterile bottle. The hemoglobin solution prepared had the following characteristics: 27 percent hemoglobin, 2 percent methemoglobin, and free of microorganisms.
The stroma-free hemoglobin solution having a concentration of 27 percent required 55.6 milliliters of hemoglobin solution to 44.4 milliliters of diluent to provide 100 milliliters as a 15 percent solution of substantially pure stroma-free hemoglobin according to the equations previously set forth. The final blood gas control was to have a pH of 7.4, P O .sbsb.2 of 105 mm. Hg. and P CO .sbsb.2 of 40 mm. Hg. at 37° C. Three aliquots of 44 milliliters each were prepared in accordance with the calculations previously set forth to obtain solutions of 0.05 molar Na 2 HPO 4 , 0.1 M/L NaCl and 2 mg./l of gentamicin sulfate. 212 milligrams, 265 milligrams and 318 milligrams of Na 2 CO 3 was added to each aliquot, respectively, thus providing three aliquots with Na 2 CO 3 levels of 20 millimole/liter, 25 millimole/liter and 30 millimole/liter, respectively. When all the Na 2 CO 3 is dissolved, each diluent aliquot was added to a respective hemoglobin aliquot of 55.6 milliliters with stirring. Ten milliliters of the diluted hemoglobin solution from each aliquot was tonometered at 25° C. with 7.5 percent O 2 and 3.5 percent CO 2 for 20 minutes. The tonometered solutions were tested on a blood gas analyzer. The pH of each solution was tested. The pH of one of the solutions was above the desired pH (which, in this case, is 7.400) and another was below that value. A linear relationship between pH and millimolarity of the Na 2 CO 3 was assumed and an aliquot was prepared based on that assumption. The new aliquot was tonometered and analyzed. This procedure was repeated until the aliquot had the desired pH (in this case, 7.400±0.010). The amount of Na 2 CO 3 as determined above was added to the bulk diluent. In this example the pH of the final adjusted aliquot was 7.402 when 27 millimoles of Na 2 CO 3 was added to an aliquot of the hemoglobin. The volume of the hemoglobin to be diluted was 30 liters and, therefore, 24 liters of the diluent containing 27 millimoles/liter of Na 2 CO 3 was added for a final volume of 54 liters. Thus, 154.5 grams of Na 2 CO 3 was added to the diluent prior to the addition of the stroma-free hemoglobin solution. The diluent as prepared above was added slowly to the hemoglobin solution with stirring. The diluted hemoglobin solution was transferred to a suitable sterile container through a Pall NR filter. A small sample was removed from the bulk hemoglobin solution and tested to determine that no bacterial growth occurred. The sterile, diluted hemoglobin solution was equilibrated with the desired amount of gas in order to obtain the desired level of pH, P O .sbsb.2 and P CO .sbsb.2. This equilibration was achieved in this specific example by prewarming the hemoglobin solution by passing it through a stainless steel coil in a 25° C.±0.2° C. water bath. The solution was passed through a series of C-DAK-2.5D artificial kidneys and into a sterile bottle containing a coil connected to a circulator bath to maintain it at 25° C.±0.2° C. A countercurrent of gas which had been prewarmed to 25° C.±0.2° C. by passage through a coil and humidified to saturation by bubbling through water at 25° C. was passed through the outside of the kidneys. The gas was then fed into the equilibration bottle to maintain an atmosphere over the solution of the same gas with which the solution was equilibrated. After all the hemoglobin solution was removed from its original container, connections were made to provide for recycling of the solution through the 25° C. coil and kidneys with return to the equilibrium container. Samples were removed from the solution during equilibration and tested on blood gas analyzers.
The equilibrated solution showed stable values for pH, P O .sbsb.2 and P CO .sbsb.2 at the target level for one hour prior to final sterile filtration.
The final bulk container, connected to the filter apparatus, was purged well with the gas having 7.5 percent O 2 and 3.5 percent CO 2 . A coil inside the container was connected to a circulator to maintain the temperature of the filtered bulk at 25° C.±0.2° C. The equilibrated bulk was pumped through the sterile filter apparatus. A slight positive gas pressure was maintained on the bulk container during transport to the filling area.
The equilibrated hemoglobin solution was filled into two ml. ampules using a fill dose of 1.5 milliliters. The ampules were preflushed with the gas mixture used for equilibration and overfilled with the same gas after filling. Discontinuous flushing using a flow of 50 cubic feet per hour was used. Bulk temperature was maintained at 25° C. by means of a coil connected to a water circulator. A slight positive pressure of the humidified gas, used for equilibration, was maintained over the bulk container.
The ampules were sealed and ready to be opened when used as a blood gas reference fluid.
EXAMPLE 2
Example 1 was repeated except that the target pH was 7.10±0.010 with P O .sbsb.2 levels and P CO .sbsb.2 levels of 155 mm. Hg and 20 mm. Hg, respectively. In order to obtain the proper pH, aliquots containing Na 2 CO 3 levels of 5 millimoles/liter, 7.5 millimoles/liter and 10 millimoles/liter were prepared and added to the aliquots of the hemoglobin solution. The tonometry results showed that 7.5 millimoles gave the desired pH. The procedure of Example 1 was followed. The final blood gas control fluid had O 2 and CO 2 levels of 154 mm. Hg and 19 mm. Hg, respectively, and a pH of 7.10.
EXAMPLE 3
Example 1 was repeated except that the target pH was 7.60±0.01 with the desired O 2 and CO 2 levels being 55 mm. Hg and 70 mm. Hg, respectively. The level of Na 2 CO 3 in the three aliquots were 40 millimoles/liter, 50 millimoles/liter and 60 millimoles/liter. Following the procedure of Example 1, 47 millimoles were determined to give the desired pH. The process was completed as in Example 1. The final pH of the blood gas control fluid was 7.60 and had an O 2 level and a CO 2 level of 54 mm. Hg and 69 mm. Hg, respectively.
Thus, in accordance with the present invention, a blood gas reference fluid is provided which is relatively stable and accurately reflects levels of blood gas constituents and pH comparable to blood samples to be analyzed. Further, in accordance with the present invention, a blood gas control fluid is provided which can be prepared at various levels of pH, P O .sbsb.2 and P CO .sbsb.2 for standardization of blood gas instrumentation.
Although the invention has been described with reference to specific materials and specific methods, the invention is only to be limited so far as set forth in the accompanying claims.
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A reference fluid for the calibration and control of blood gas instruments is comprised of substantially pure stroma-free hemoglobin solution, a buffering agent, a source of bicarbonate ion and predetermined amounts of gases found in in vivo blood.
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BACKGROUND OF THE INVENTION
The field of the invention is engine generator sets, and particularly, small compact generator units for portable use or for use in recreational vehicles.
Small, vertical shaft engine generator sets such as those disclosed in U.S. Pat. Nos. 4,450,888 and 4,677,940 include a small gasoline or gas powered engine which rotates the rotor of an electric generator. Heat is produced by both the engine and generator and this heat must be removed for proper system operation. Portable generators are housed in a compact, aesthetically pleasing enclosure, and generators for recreational vehicles are housed in compact compartments formed in the vehicle. In both applications the proper removal of heat is a significant design challenge.
The conventional solution for removal of heat is to provide separate cooling fans for the engine and the generator. As disclosed in the above-cited patents, for example, a fan is disposed on top of the engine and is driven by the vertical engine shaft to blow cooling air over the air-cooled engine. The generator is mounted below the engine, and the generator rotor and a generator cooling fan are both driven by the vertical engine shaft. The generator cooling fan cools the generator stator windings and it may also provide some engine cooling as well. The use of two fans in systems such as these is expensive, and the use of two fans increases the vertical height of the generator set.
A vertical shaft, engine generator set which employs a single cooling fan is disclosed in U.S. Pat. Nos. 4,779,905 and 4,856,470. In these systems cooling air is drawn in over the engine and then around the generator stator windings before being exhausted. Because the engine is cooled first, proper cooling of the more sensitive generator windings is problematic, particularly when a more compact generator construction is used. Also, there is no provision for cooling electronic circuitry which is used on state-of-the-art generator sets to regulate generator output voltage.
SUMMARY OF THE INVENTION
The present invention is a compact, vertical shaft engine generator set in which the generator is disposed above the engine and a single fan is disposed above the generator to blow cooling air over the generator stator windings, the electronic generator control circuitry and the engine. More particularly, the engine generator set includes an air-cooled engine which rotates a vertically disposed shaft that extends upward from the engine and which has a heat producing cylinder head that extends laterally outward to one side of the engine; a generator mounted above the engine and having a rotor coupled for rotation by the shaft and a stator with its windings disposed around the rotor; a fan mounted above the generator and coupled for rotation by the shaft to blow cooling air downward and over the stator windings; a plenum formed around the fan to direct the air over the stator windings; and an air duct coupled to the plenum to direct cooling air downward from the plenum to cool the engine cylinder head. Electronic circuitry used to control generator output voltage is mounted adjacent to the air duct and electronic components therein are cooled by cooling air flowing in the air duct.
A general object of the invention is to cool the engine and generator with a single fan. By mounting the generator above the engine, its windings and associated electronic circuitry can be cooled first by cool air drawn in from the top and directed downward through the air duct to the engine cylinder head. The heated air is exhausted through an opening in the bottom panel of a surrounding enclosure.
A more specific object of the invention is to cool generator electronic components with the same fan used to cool both generator and engine. The heat producing electronic components are mounted to the plenum wall or air duct which serve as a heat sink, or a heat sink is mounted in the air flow through the air duct.
Another object of the invention is to reduce the height of a vertical shaft engine generator set. By making efficient use of the large radial area above the engine, the stack height of the generator rotor and surrounding stator windings is kept to a minimum.
A more specific object of the invention is to reduce the axial height of the fan. By contouring the shape of the fan blades to the profile of the stator windings, the fan is compactly mounted above the generator with minimal increase in height.
Yet another object of the invention is to reduce the temperature of combustion air supplied to the enclosed engine. The plenum is coupled to a housing formed around the air filter at the air intake of the engine, and combustion air is supplied from the plenum.
The foregoing and other objects and advantages of the invention will appear from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown by way of illustration a preferred embodiment of the invention. Such embodiment does not necessarily represent the full scope of the invention, however, and reference is made therefore to the claims herein for interpreting the scope of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the preferred embodiment of the engine generator set which employs the present invention;
FIG. 2 is a perspective view of the engine generator set of FIG. 1 with the enclosure removed;
FIG. 3 is a top view of the engine generator set of FIG. 2 with parts cut away;
FIG. 4 is a view in cross section taken through the plane 4--4 indicated in FIG. 3;
FIG. 5 is a side elevation view of the engine generator set of FIG. 1 with parts cut away; and
FIG. 6 is a front elevation view of the engine generator set of FIG. 1 with parts cut away.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring particularly to FIG. 1, the engine generator set is enclosed in a housing 1 having a front panel 2, side panels 3 and a top panel 4. A control panel 5 is disposed on the front panel 2 and both cooling air and combustion air are drawn in through louvers 7 formed in the top panel 4. Both combustion air and cooling air are exhausted through openings in the bottom (not shown in the drawings) of the housing 1.
Referring to FIGS. 1 and 2, the engine combustion air is passed through an air filter 10 into an internal combustion engine 12 which is oriented inside the housing 1 with its crank shaft 14 vertical and its cylinder head 16 extending horizontally towards the front panel 2. A substantially cylindrical plenum 18 is formed beneath the top panel 4 by an upright sheet metal wall 20 mounted to the top of the engine 12. The plenum 18 surrounds a centrifugal fan 22 which is rotated by the engine shaft 14 to draw air in through the louvers 7 and direct it downward and radially outward against the surrounding plenum wall 20. The air filter 10 is enclosed by a cover 6, and combustion air is received through an opening 8 in the plenum wall 20.
Referring particularly to FIGS. 3 and 4, the centrifugal fan 22 is fastened to a flywheel 26 by bolts 28. The flywheel 26 is in turn fastened to the end of the engine crank shaft 14 by bolt 30. Sandwiched between the fan 22 and the flywheel 26, and held in place by bolts 28, is the rotor 32 of the generator. The rotor 32 is comprised of stacked steel laminations constructed as described in co-pending U.S. patent application Ser. No. 335,408 filed on Dec. 9, 1994 and entitled "Rotor With Embedded Rare-Earth Permanent Magnets". The rotor 32 extends radially outward from the shaft 14 and defines the inner surface of a circular, cylindrical generator air gap 34. The outer boundary of the air gap 34 is defined by the stacked steel laminations of a generator stator 36 which is fastened to the top of generator adapter 12 by bolts 38. The stator windings 40 are supported by these laminations and they extend upward and downward therefrom. Blades 42 on the centrifugal fan 22 are cut away along their lower edge 43 to provide clearance for the upward extending stator windings 40 while maintaining the height of these elements to a minimum.
Referring particularly to FIG. 4, when the shaft 14 is rotated by the engine, the flywheel 26, the rotor 32 and the centrifugal fan 22 are rotated about its vertical axis. The fan 22 draws cooling air downward and blows it radially outward over the stator windings 40 as indicated by arrows 44. As shown by arrows 46 in FIG. 3, this cooling air is corralled by the plenum wall 20 and directed forward and downward towards the engine cylinder head 16, as will now be described in more detail.
Referring particularly to FIGS. 3, 5 and 6, the walls 20 of the plenum 18 are extended forward and downward to form an air duct which directs cooling air from the plenum 18 to the engine cylinder head 16. More specifically, the air duct is formed by a vertical sheet metal wall 5a which extends forward from the plenum wall 20 to the front panel 2 adjacent the air cleaner 10, and extends downward along one side of the cylinder head 16. A second vertical sheet metal wall 52 spaced away from the wall 50 extends forward from the plenum wall 20 to the front panel 2 and extends downward to the other side of the cylinder head 16. The top edge of this wall 52 angles downward from the plenum wall 20 and supports an electronics support wall 54 that slopes downward and forms the top of the air duct. The air duct formed by walls 50, 52 and 54 deflects cooling air downward and around the cylinder head 16.
An electronics circuit board 56 mounts to the support wall 54 and it includes heat sinks 58 that extend downward into the cooling air stream through an opening 60 formed in the support wall 54. Cooling air is forced from the plenum 18, through the air duct and around the cylinder head 16. The electronics circuit 56 is mounted to this air duct and is cooled by the air flowing therethrough. Also, as shown best in FIG. 2, electronic components such as diodes or SCRs 64 that produce large amounts of heat can be mounted directly to the walls of the plenum 18 or air duct. In this case, the cooled metal wall serves as a heat sink for the electronic component.
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An engine driven generator set includes a vertical shaft engine which rotates a generator rotor and a centrifugal fan mounted above the engine. A plenum collects cooling air blown over generator stator windings by the fan and directs the cooling air through an air duct over the engine cylinder head. Electronic circuitry is cooled by this same cooling air.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent application claims priority to the Patent Application of Kazakhstan No. 2013/1925.1 filed on Dec. 23, 2013, currently allowed. It is also Continuation-in-part of U.S. patent application Ser. No. 13/864,385 filed on Apr. 17, 2013, and Ser. No. 13/864,399 filed on Apr. 17, 2013, both currently allowed.
FIELD OF INVENTION
[0002] The invention relates to the non-ferrous metallurgy industry and can be used to extract beryllium from bertrandite and phenakite groups under the conditions of processing mineral raw materials (ores, concentrates via heap, vat leaching).
BACKGROUND
[0003] The object of the invention is to develop a method for extracting beryllium from bertrandite (Be4(Si2O8)(OH)2)} and phenakite (Be2(SiC4)) groups that permits expanding the range of mineral raw materials that can be included in processing and provides an economical and more environmentally friendly production due to the use of effective active reagent at low-temperature modes of the hydrochemical method.
[0004] Modern methods for extracting beryllium from the aforementioned mineral in part from ore and concentrates is performed only by the pyrometallurgical method at a high temperature.
[0005] The disadvantages of pyrometallurgical production of beryllium extraction are harmful toxic gas emission, high energy costs, the need for refractory materials, which are not beneficial either economically or ecologically (Everest D. Beryllium chemistry.—M.: Chemistry, 1968; Plyushchev E. P., Stepina S. V., Fedorov P. I. Chemistry and technology of rare and trace elements. Part 1./under ed. Bolipakova. —M.: Higher education institution, 1976. —p. 186-221; Silina G. F., Zarembo Y. I., Bertina L. E. Beryllium. Chemical technology and metallurgy/under ed. V. I. Spitsina. —M.: Atomizdat, 1960. —p. 20-35).
[0006] Replacing the high-temperature method of extracting beryllium from beryllium-containing raw materials represented primarily in the form of minerals: bertrandite (Be4(Si2O8)(OH)2)} and phenakite (Be2(SiC4)) concentrates with a cheaper hydrochemical method using effective solvents is highly pressing.
[0007] The object of the invention is to develop a novel method for extracting beryllium from bertrandite and phenakite, which permits expanding the range of raw minerals used for processing and provides more economical production and improved environmental impact via use of an effective active reagent at low temperatures by hydrochemical method, which has no analogues in worldwide application.
[0008] A technical solution relatively similar to the invention is the method for dissolving bertrandite-phenakite concentrate via processing it using a sulfate method (a variant of Brush-Beryllium method) after thermal processing with an 85% concentrated sulfuric acid at a temperature of 300° C. in thermostabilized conditions (UMF, City of Ust-Kamenogorsk) (Plyushchev E. P., Stepina S. V., Fedorov P. I. Chemistry and technology of rare and trace elements. Part 1./under ed. Bolipakova. —M.: Higher education institution, 1976. —p. 186-221). A disadvantage of the known method is compliance with safety regulations and complexity of the process of breaking down sulfuric acid.
[0009] Even closer in essence is our previously proposed novel method for extracting beryllium from beryllium concentrate containing mainly bertrandite and phenakite minerals using an extremely hard-to-access, expensive, and toxic reagent with a hot solution of potassium bifluoride (KNF2) in the presence of HCl:H 2 O=1:1 during continuous heating up to 80° C. for a duration of 8 hours.
[0010] In relation to the aforementioned, in order to eliminate the above-mentioned disadvantages it is essential to find a cheaper, less toxic, and effective active reagent-solvent for beryllium minerals, which can successfully replace potassium bifluoride during hydrometallurgical processing of beryllium-containing raw materials.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0011] The object of the invention is developing a method for extracting beryllium from bertrandite (Be4(Si2O8)(OH)2)} and phenakite (Be2(SiC4)) groups, which permits expanding the range of raw minerals used for processing and provides more economical production and improved environmental impact via use of an effective active reagent at low temperatures by hydrochemical method, which has no analogues in worldwide application.
[0012] Due to this, additional studies were conducted to develop more effective and cheaper methods of extracting beryllium from bertrandite and phenakite groups under the conditions of processing mineral raw materials (ore, concentrate).
[0013] Leaching beryllium-containing raw material from beryllium minerals from bertrandite and phenakite groups is performed by contacting monomineral samples, ore or concentrate, with leaching agents: hydrochloric acid and water (1:1), in the absence as well as presence of ammonium fluoride in the range of 1-8 g in hydrochloric acid medium followed by beryllium extraction using 0.5 liters of solution within a hydrochloric acid range between 2 to 12% in the presence of the above-mentioned reagent at S:L=1:5 while steadily heating over the course of 8-10 hours at a heating temperature of 25°-80° C.
[0014] The effective action of solvents, as complexing agents as well as oxidizing agents, depends on the pH of the solution. Therefore, the choice of hydrochloric acid as the medium and dissolving reagent (solvent) is due to the hydrochloric acid, acting as a acid reagent, also simultaneously performs the functions of a complexing reagent, i.e. supplier of chloride ions into the reaction medium for bonding metal ions in the compound. This is the main advantage of hydrochloric acid compared to the widely-used sulfuric acid. In the case of using sulfuric acid in practice the transfer of beryllium ions from the solid phase into the solution sharply decreases due to the blocking of surface minerals containing the aforementioned metals, formed by low-solubility sulfates of associated metals, such as calcium, barium, lead, and magnesium.
[0015] Using hydrochloric and chloride methods for leaching beryllium ions is based on the high solubility of the resulting complex chlorides.
[0016] The role of hydrochloric acid can be summarized in that is not only inhibits hydrolysis, but also forms stable bonding of BeCl (Everest D. Beryllium chemistry. —M.: Chemistry, 1968; Plyushchev E. P., Stepina S. V., Fedorov P. I. Chemistry and technology of rare and trace elements. Part 1./under ed. Bolipakova. —M.: Higher education institution, 1976. —p. 186-221; Silina G. F., Zarembo Y. I., Bertina L. E. Beryllium. Chemical technology and metallurgy/under ed. V. I. Spitsina. —M.: Atomizdat, 1960.—p. 20-35).
[0017] We carried out initial experimental studies on dissolution only in hydrochloric acid with consequent heating of the reaction mixture from 25 to 80° C. of monomineral samples of the above-mentioned beryllium-containing minerals (mineral purity: bertrandite—98.5, phenakite—98.3). Verification of the data on monomineral samples of bertrandite and phenakite under conditions of a hydrochloric acid concentration of 0.8 to 12% (by mass) has shown that at a hydrochloric acid concentration of 0.8% no more than 5% of beryllium was extracted from bertrandite and 2% from phenakite (Table 1). Only increasing the concentration to 12% or more leads to almost complete dissolution.
[0000]
TABLE 1
Beryllium extraction (in %) from bertrandite and phenakite groups
depending on hydrochloric acid concentration. Minerals weighed
100 mg. Solution volume 200 mL. Duration of 8 hours at
continuous heating from 25° to 80° C.
Hydrochloric acid
concentration, %
Minerals
.8
.2
.4
.0
.0
2.0
Beryllium extraction from minerals, %
Bertrandite
5
2
0
8
Phenakite
.2
6
8
8
5
[0018] Our preliminary experimental results of studying bertrandite, phenakite behavior depending on hydrochloric acid concentration allowed us to obtain information regarding primary factors that influence the process being studied: hydrochloric acid concentration, duration of mixing, temperature.
[0019] With the goal of finding more effective variants of optimal conditions for complete dissolution of bertrandite and phenakite, an orthogonal experiment design of the 2nd order with “axial distance” α=±1,215 was used.
[0020] The ratio of components, including the concentration of hydrochloric acid used during leaching, was experimentally chosen using a multifactorial orthogonal experiment design method. Deviation from it leads to decreased level of beryllium extraction from beryllium-containing raw materials.
[0021] To confirm the obtained technical result of the proposed method, examples of implementation are provided: the experiment was performed in a 500 mL volume of leaching solution, respectively, with a ratio of S:L=1:5. The degree of extraction was determined using existing methods.
Example 1
[0022] A 500 mL cold solution of technical hydrochloric acid of 12% concentration (by mass) was poured into a 0.500 g weighed portion of bertrandite and phenakite (separately) monominerals. The components were gradually heated from 25° C. to 80° C. for 8 hours. Results of the experiment are shown in Table 2.
Example 2
[0023] The experiment is performed analogously to Example 1, but with a technical hydrochloric acid concentration value of 8% (by mass). Results are also shown in Table 2.
Example 3
[0024] The experiment is performed analogously to Examples 1-2, but with a technical hydrochloric acid concentration value of 0.8% (by mass). Results are also shown in Table 2.
[0000]
TABLE 2
Results of the multifactorial experiment using orthogonal
design experiment of the 2nd order α = ±1,215.
Experiments were conducted separately for bertrandite and
phenakite on the same planning matrix. Weighed portion 500 mg.
Test conditions: cold solution of hydrochloric acid of
varying concentrations; with gradual heating from cold
to 80° C. for 8 hours. Beryllium extraction in %
Example 1
Example 2
Example 3
Beryllium
(12% HCl
(8% HCl
(0.8% HCl
No
minerals, %
by mass)
by mass)
by mass)
1
Bertrandite
98.0; 96.0; 97.0;
81.0; 82.0; 80.5
5.7; 5.5; 5.2
2
Phenakite
95.0; 94.0; 94.5
78.0; 77.0; 76.8
2.0; 2.5; 2.3
[0025] Based on the experimental data (Table 2) obtained using the proposed method, the following optimal conditions for the most effective extraction of beryllium from bertrandite and phenakite were chosen: 500 mL of 12% cold hydrochloric acid solution by mass with gradual heating for 8 hours from 25° C. to 80° C. Under these conditions, the degree of beryllium extraction from bertrandite and phenakite was determined, and they are 97-98% and 94-95%, respectively. Use of a 12% cold solution of HCl:H2O-1:1 by mass with gradual heating from 25° C. to 80° C. for 8 hours is due to the fact using a hot solution creates a large quantity of silicic acid, which inhibits the process of dissolving beryllium minerals by blocking their surfaces. This leads to decreased beryllium extraction from bertrandite-phenakite concentrates. Previously, hot solutions of 1:1 hydrochloric acid was used for extracting beryllium from genthelvite groups (Innovative Patent RK No. 12 26589, MRK COIF 1/00, C22B 35/00, publ. bulletin No. 1212 from 25.12.2012). However, genthelvite groups have greater reactivity than bertrandite and phenakite groups (Ospanov K. K. General principles of prediction of differences of minerals and “solvents” reactivity in the processes of mineral raw materials processing (On materials of 3 international scientific discoveries. Student's book—Almaty: TOO <<BTS paper>>, 2012. —p 367).
[0026] The proposed method of extracting beryllium from bertrandite and phenakite mineral groups was also tested directly on bertrandite and phenakite concentrates provided by UMF (City of Ust Kamenogorsk) with initial content of 4.18%.
[0027] Extraction technique: 500 mL of cold hydrochloric solution of varying concentrations was poured on a weighed portion of 25 g of concentrate and gradually heated on the plate for 10 hours from a temperature of 25° C. to 80° C., since the object is bertrandite and phenakite concentrate. Cooled and filtered, the beryllium content was determined by physical method. It comprised 90-91%. Results are shown in Table 3.
[0000]
TABLE 3
Results of validation of beryllium extraction from bertrandite-
phenakite concentrate with initial content of 4.18%. Weighed
portion of 25 g of concentrate. The volume of the solution
is 500 mL of 12% hydrochloric acid by mass with gradual
boiling from 25° C. to 80° C. for 8 hours. Results
are the mean of 4 experiments.
Total content of Be in
Obtained value of Be
concentrate, in % by mass
from concentrate in %
4.18
91.0; 90.5; 90.7; 90.8; 90.6; 91.0
[0028] During the next step, for intensification, i.e. increasing the degree of beryllium extraction from bertrandite-phenakite concentrate, a less toxic, easily accessible, cheap reagent, ammonium fluoride (NH4F), was used. The concentration of ammonium fluoride was varied from 1 to 8%, leaving the concentration and volume of hydrochloric acid and extraction conditions unchanged.
[0029] The technique for extracting bertrandite-phenakite beryllium concentrate: 500 mL of cold solution (25° C.) of hydrochloric acid HCl:H2O=1:1 was poured over 25 g and 10 g weighed portions and 1-8 g of ammonium fluoride (NH4F) was added and gradually heated on a plate for 10 hours at a temperature of 25° C. to 80° C.
[0030] Since a single administration of solvent reagent (NH4F) ammonium fluoride in hydrochloric acid medium does not provide high beryllium extraction, additional experiments were performed with portioned introduction of ammonium fluoride of 2 g every 2 hours, which, as proposed, allows maintaining a greater concentration of ammonium fluoride for a duration of 10 hours with gradual heating from 25° C. to 80° C.
[0031] Next, the reaction mixture is cooled and filtered. The filtrate is retained for settling of beryllium ions. Part of the solution (in 15 mL volumes of each of the 4 replicated tests) was sent out to determine its content of beryllium that has changed from solid phase into a solution. This showed that portioned introduction of ammonium fluoride into a 1:1 hydrochloric acid medium while maintaining a specified solution acidity is more effective than a one-time addition. Extraction of beryllium that has changed from the solid phase into a solution was 93-94% under these conditions.
[0032] For burden balance calculations, the precipitate was dried after extraction from bertrandite-phenakite concentrate using a 1:1 hydrochloric acid solution in the presence of 8 g NH4F (ammonium fluoride) (fractional method) with heating from 25° C. to 80° C. for 10 hours. Then 1 g of precipitate was fused with Na2CO3+K2CO3 in a platinum crucible. The alloy was cooled and transferred to the solution. Beryllium content was determined. The beryllium content found in the precipitate ranged from 1.9 to 4.03%. It was factually confirmed that the degree of beryllium extraction from the solution actually corresponds to 93-94%. The aforementioned data were obtained in the laboratory of elemental analysis at the Institute for Nuclear Physics (Alatau, Almaty) using the methods of mass-spectrometry and inductively coupled plasma.
[0033] The degree of beryllium extraction from the stated bertrandite-phenakite concentrate sharply increased to 93-94%. This is due to the fact that, when using potassium bifluoride, a highly viscous medium is formed, which hinders the mobility of beryllium ions, and leads in turn to inhibition of the beryllium mineral dissolution process. At the same time, in the presence of ammonium fluoride, this does not occur. Furthermore, as mentioned above, using a hot solution creates a large quantity of silicic acid, which inhibits the dissolution of beryllium minerals by blocking their surfaces.
[0000]
TABLE 4
Results of beryllium extraction from bertrandite-phenakite concentrate
using an ammonium fluoride dissolution reagent in the range of 1-8%
concentration by mass (NH4F). Weighed portion of 25 g concentrate.
Solution volume of 500 mL. Hydrochloric acid 1:1 with continuous
heating for 8 hours at temperatures from 25° C. to 80° C.
Initial Be concentrate content of 4.18%.
Concentration of ammonium
Degree of Be
fluoride, in % by mass
extraction, %
1
90.5; 91.0; 91.3; 91.2; 90.5
2.5
90.8; 90.6; 91.5
5
91.0; 91.3; 91.5; 91.0; 91.1; 91.8
8
93.0; 93.5; 93.6; 93.8; 94.0; 94.1
[0034] Thus, the most economically and environmentally beneficial and effective dissolving reagent for extracting beryllium from bertrandite-phenakite concentrate is that according to invention claims 1 and 2 . It should be noted that under conditions of dissolving bertrandite and phenakite all beryllium minerals are dissolved, except beryllium.
[0035] Gradual heating of hydrochloric acid solution HCl:H2O=1:1 for 8 hours from 25° C. to 80° C. Beryllium extraction is 90-91%.
[0036] Using an 8% solution (by mass) of ammonium fluoride (fractional method) in the same 1:1 hydrochloric acid solution with successive heating for 10 hours from 25° C. to 80° C. Beryllium extraction is 93-94%.
[0037] The description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in this art. It is intended that the scope of the invention be defined by the following claims and their equivalents.
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The invention relates to the non-ferrous metallurgy industry and can be used for extracting beryllium from bertrandite and phenakite groups under conditions of processing of mineral raw materials (ore, concentrate) by heap, vat leaching.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This Application claims the benefit of U.S. Provisional Application 61/374,529, filed Aug. 17, 2010, and hereby incorporated by reference.
BACKGROUND
[0002] The present invention relates to a method of stabilizing and/or sterilizing peptides or proteins by irradiating a composite of a peptide and/or a protein incorporated in a polymeric matrix with β radiation.
[0003] Common sterilization processes used in the pharmaceutical industry for dry solid materials include dry-heating, steam autoclaving, use of chemical agents (e.g. hydrogen peroxide), use of gaseous agents (e.g. ethylene oxide), and irradiation by ultraviolet light or γ-radiation. But few good options are available for sterilizing proteins in a dry solid state. Dry heat and steam methods involve high heat that destroys protein structure and activity. Chemical agents and ethylene oxide gas also degrade proteins and, in addition, ethylene oxide is carcinogenic. γ-irradiation has high penetrating power and is commonly used for sterilizing medical devices. However, the extended exposure time (hours) to accumulate a sterilizing dose is known to cause localized heating, and traces of water in the dry protein lead to the generation of chemically reactive oxygen radicals. As a result, gamma-irradiation is often associated with irreversible alteration in protein conformation at the molecular level, especially when the protein contains one or more disulfide bonds or easily oxidized methionine residues. In order to prevent radical-induced degradation, antioxidants such as carotenoids or ascorbate are often added to pharmaceutical preparations. It has been reported that L-tyrosine may be used to prevent aggregation during gamma-irradiation of certain proteins in aqueous solution. The stabilization of proteins in solution by polyols such as mannitol, sucrose, glycerol, and lactose has also been studied.
BRIEF SUMMARY OF THE INVENTION
[0004] It has now been discovered that terminal sterilization of freeze-dried therapeutic proteins such as 1121 Fab, a protein available from ImClone, that have been incorporated into a bioabsorbable, biodegradable polymer matrix such as poly(D,L-lactide co-glycolide) (PLGA) may be accomplished by electron beam (β) irradiation, i.e. by high energy electrons or “E-Beam”. (See published US Patent Applications 20090203039 and 200900226399, at paragraphs [0079] and [0047], respectively, for a disclosure of Fab. See, also, “Tailoring in Vitro Selection for a Picomolar Affinity Human Antibody . . . ” 278 The Journal of Biological Chemistry 43496-43507 Oct. 30, 2003 wherein certain uses of 1121 Fab are disclosed.)
[0005] In one embodiment, the present invention is directed to a method for sterilizing a biodegradable implant, said implant comprising a polypeptide and a biodegradable polymer matrix, the method comprising
a. mixing said polypeptide with an excipient in aqueous solution to form an admixture, said excipient selected from the group consisting of sucrose, trehalose, and glycine, followed by b. lyophilizing said admixture, followed by c. incorporating the lyophilized admixture into a biodegradable polymer matrix, thereby forming a biodegradable implant for the release of said polypeptide in a tissue of a mammalian subject, followed by d. irradiating the implant with β-radiation, such that the implant receives a dose of β-radiation of between about 1.5 to about 4.0 megarads (Mrad), thereby sterilizing the biodegradable implant.
[0010] The polypeptide can be any desired protein, including any therapeutic protein, antibody, or peptide. Incorporating the lyophilized admixture into a biodegradable polymer matrix may comprise blending the admixture with one or more biodegradable polymers, and then extruding (e.g., hot melt extruding) the blend to thereby form the implant. Blending a lyophilized admixture into a biodegradable polymer matrix generally involves blending the dry, lyophilized admixture with one or more dry biodegradable polymers (i.e., a blending of dry powders). The biodegradable polymer matrix may comprise one or more biodegradable polymers selected from the group consisting of methylcellulose, carboxymethylcellulose, hydroxymethylcellulose hydroxypropylcellulose, hydroxyethylcellulose, ethyl cellulose, chitosan, polylactide-co-glycolide (PLGA), polylactic acid (PLA), polyglycolide, polyhydroxybutyric acid, poly(ε-caprolactone), poly(γ-caprolactone), poly(δ-valerolactone), hyaluronic acid, and polyorthoesters. The biodegradable polymer matrix may comprise polymeric microspheres. The microspheres may comprise one or more biodegradable polymers selected from the group consisting of poly(D,L-lactide co-glycolide) and polylactide (PLA).
[0011] In a specific embodiment, the biodegradable implant may be sized and configured as an intraocular implant. In another embodiment, the implant may be sized and configured for use as an interarticular implant, as for example one that can be used as a therapeutic implant in a joint to treat a condition, disease, disorder, or inflammation of a joint. The polypeptide may include one or more disulfide bonds or methionine residues. In a specific embodiment, the lyophilized protein admixture comprises 3 to 5% sucrose by weight. The mammalian subject can be a human or non-human mammal, including but not limited to a mouse, rat, rabbit, dog, horse, pig, and guinea pig.
[0012] Also within the scope of the present invention is a sterile biodegradable implant comprising a polypeptide, such as an antibody, wherein said implant is produced according to the method described above.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 shows the results of Example 1 wherein the specific binding activity of a soluble released protein after irradiation with high energy electrons is measured using ELISA (enzyme-linked immunosorption assay).
[0014] FIG. 2 shows the results of Example 1, wherein the total release of non-aggregated protein after irradiation with high energy electrons is measured using SEC-HPLC (size exclusion chromatography).
DETAILED DESCRIPTION OF THE INVENTION
[0015] The following terms as used herein are defined as follows:
[0016] “Sterile” means free from living organisms including microorganisms and their spores.
[0017] “Biodegradable polymer” means a polymer or polymers which degrade in vivo, and wherein erosion of the polymer or polymers over time occurs concurrently with or subsequent to release of the therapeutic agent. The terms “biodegradable” and “bioerodible” are equivalent and are used interchangeably herein. A biodegradable polymer may be a homopolymer, a copolymer, or a polymer comprising more than two different polymeric units.
[0018] “Intraocular implant” means a device or element that is structured, sized, or otherwise configured to be placed “in an eye” of a living mammal, including the subconjunctival space, without causing adverse side effects. In certain embodiments, the intraocular implant may be sized and configured for placement in the vitreous body of the eye, and thereby referred to as an intravitreal implant.
[0019] As used herein “a peptide” is a polymer of between about 3 and about 50 contiguous amino acids in length, wherein the amino acids are linked by peptide bonds. In certain embodiments, a peptide is 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, or 50 contiguous amino acids in length. A peptide can be linear, branched, or circular.
[0020] As used herein “a polypeptide” means peptides as well as full-length proteins, which proteins may be enzymes or structural proteins, including antibodies (monoclonal or polyclonal). The proteins for use in the present implants may be produced recombinantly or isolated from natural sources.
[0021] In the present method for sterilizing peptide and protein implants and polymeric composites using β-irradiation, localized heating is negligible due to very short exposure times at a high dose rate (kGy/sec for β rays compared to kGy/hour for gamma-rays). No residual radioactivity or chemical agents are present after treatment. In the case of proteins that contain disulfide bonds, such as 1121 Fab, it has been discovered that lyophilizing the protein in the presence of sucrose, e.g. 3-5% (w/w) sucrose, prior to adding the protein to the anhydrous polymer matrix (e.g., PLGA) significantly improves protein stability following β irradiation. These results were compared to the stabilizing effects of adding an equal concentration of the disaccharide trehalose, the amino acid glycine, or a “no excipient” control. A higher cumulative release of soluble, non-aggregated protein or of soluble binding activity is suggestive of less denaturation and less formation of insoluble aggregates within the polymer matrix.
[0022] Thus, in one embodiment the present invention is directed to a method for sterilizing a protein, such as an antibody, the method comprising mixing said protein with sucrose, in an aqueous solution, to form a protein admixture, lyophilizing said protein admixture, incorporating said lyophilized protein admixture in a bioabsorbable polymer matrix such as poly(D,L-lactide co-glycolide) to form a composite of said protein admixture and said polymer and irradiating said composite with high energy electrons or “E-Beam”, i.e. with β radiation.
[0023] The present invention also provides a method of sterilizing proteins, including antibodies, such as 1121 Fab which comprises incorporating said protein in a bioabsorbable polymer matrix such as poly(D,L-lactide co-glycolide) to form a composite of said protein and said polymer and irradiating said composite with β radiation, i.e. high energy electrons or “E-Beam”.
[0024] The present invention also provides a method of sterilization of proteins such as 1121 Fab which have been incorporated in a bioabsorbable and biodegradable polymer matrix such as poly(D,L-lactide co-glycolide) to form a composite of said protein and said polymer by irradiating said composite with with β radiation, i.e. high energy electrons or “E-Beam”.
[0025] In one aspect of this invention, the composites formed by the method of this invention are used as implants for delivering the protein or peptide to the body of a patient in need thereof. For example, the implant, i.e. an intraocular implant, may be sized accordingly and inserted into the eye of a patient.
[0026] In the method of the present invention, a beam of electrons (β-radiation) is used as the radiation source. A beam of electrons has the advantages of high dose rates (e.g., 1, 5, or even 10 Mrad per second), high throughput, less containment, and less confinement equipment. Electron beams can also have up to 80 percent electrical efficiency, allowing for a low energy usage, which can translate into a low cost of operation and low greenhouse gas emissions corresponding to the small amount of energy used. In addition, electrons having energies of 4-10 MeV can have a penetration depth of 5 to 30 mm or more, such as 40 mm, which is more then sufficient to completely sterilize the products of this invention.
[0027] Electron beams can be generated, e.g., by electrostatic generators, cascade generators, transformer generators, low energy accelerators with a scanning system, low energy accelerators with a linear cathode, linear accelerators, and pulsed accelerators. Electrons as an ionizing radiation source can be useful, e.g., for relatively thin piles of materials, e.g., less than 0.5 inch, e.g., less than 0.4 inch, 0.3 inch, 0.2 inch, or less than 0.1 inch. In some embodiments, the energy of each electron of the electron beam is from about 0.3 MeV to about 2.0 MeV (million electron volts), e.g., from about 0.5 MeV to about 1.5 MeV, or from about 0.7 MeV to about 1.25 MeV.
[0028] The above described sterilized composites of a protein and a biocompatible polymer may be used as implants. For example, the sterilized composites may be sized and structured for use as intraocular implants, intra-articular implants, sub-dermal, or subcutaneous implants. The method of making the implants of the invention is described to illustrate the present invention.
[0029] In a first step in the method of the present invention, a protein is incorporated in to a polymeric matrix as disclosed below.
[0030] Various techniques may be employed to produce the implants, e.g. the intraocular implants, described herein. Useful techniques include, but are not necessarily limited to, solvent evaporation methods, phase separation methods, interfacial methods, molding methods, injection molding methods, extrusion methods, co-extrusion methods, carver press method, die cutting methods, heat compression, combinations thereof and the like.
[0031] Examples of specific methods are discussed in U.S. Pat. No. 4,997,652, incorporated entirely by reference. Extrusion methods may be used to avoid the need for solvents in manufacturing. When using extrusion methods, the polymer and drug (protein) are chosen so as to be stable at the temperatures required for manufacturing, usually at least about 85° C. Extrusion methods use temperatures of about 25° C. to about 150° C., more preferably about 65° C. to about 130° C. An implant may be produced by bringing the temperature to about 60° C. to about 130° C. for drug/polymer mixing, such as about 90° C., for a time period of about 0 to 1 hour, 0 to 30 minutes, or 5-15 minutes. For example, a time period may be about 10 minutes, preferably about 0 to 5 min. The implants are then extruded at a temperature of about 60° C. to about 130° C., such as about 75° C.
[0032] In addition, the implant may be coextruded so that a coating is formed over a core region during the manufacture of the implant.
[0033] Compression methods may be used to make the implants, and typically yield implants with faster release rates than extrusion methods. Compression methods may use pressures of about 50-150 psi, more preferably about 70-80 psi, even more preferably about 76 psi, and use temperatures of about 0° C. to about 115° C., more preferably about 25° C.
[0034] The implants of the present invention may be inserted into the eye, for example the vitreous chamber of the eye, by a variety of methods, including placement by forceps or by trocar following making a 2-3 mm incision in the sclera. The method of placement may influence the therapeutic component or drug release kinetics. For example, delivering the implant with a trocar may result in placement of the implant deeper within the vitreous than placement by forceps, which may result in the implant being closer to the edge of the vitreous.
[0035] Among the diseases/conditions which can be treated or addressed in accordance with the present invention include, without limitation, the following: Ocular conditions selected from the group consisting of: macular degeneration, age related macular degeneration, non-exudative age related macular degeneration, exudative age related macular degeneration, choroidal neovascularization, retinopathy, diabetic retinopathy, acute and chronic macular neuroretinopathy, central serous chorioretinopathy, macular edema, cystoid macular edema, and diabetic macular edema, acute multifocal placoid pigment epitheliopathy, Behcet's disease, birdshot retinochoroidopathy, syphilis, lyme disease, tuberculosis, toxoplasmosis, uveitis, intermediate uveitis, pars planitis, and anterior uveitis, multifocal choroiditis, multiple evanescent white dot syndrome, ocular sarcoidosis, posterior scleritis, serpignous choroiditis, subretinal fibrosis, uveitis syndrome, Vogt-Koyanagi-Harada syndrome, retinal arterial occlusive disease, central retinal vein occlusion, disseminated intravascular coagulopathy, branch retinal vein occlusion, hypertensive fundus changes, ocular ischemic syndrome, retinal arterial microaneurysms, Coat's disease, parafoveal telangiectasis, hemi-retinal vein occlusion, papillophlebitis, central retinal artery occlusion, branch retinal artery occlusion, carotid artery disease, frosted branch angitis, sickle cell retinopathy and other hemoglobinopathies, angioid streaks, familial exudative vitreoretinopathy, Eales disease, sympathetic ophthalmia, uveitic retinal disease, retinal detachment, eye trauma, laser induced eye damage, photocoagulation, eye hypoperfusion during surgery, radiation retinopathy, bone marrow transplant retinopathy, proliferative vitreal retinopathy, appearance of epiretinal membranes, proliferative diabetic retinopathy, ocular histoplasmosis, ocular toxocariasis, presumed ocular histoplasmosis syndrome, endophthalmitis, toxoplasmosis, retinal diseases associated with HIV infection, choroidal disease associated with HIV infection, uveitic disease associated with HIV Infection, viral retinitis, acute retinal necrosis, progressive outer retinal necrosis, fungal retinal diseases, ocular syphilis, ocular tuberculosis, diffuse unilateral subacute neuroretinitis, myiasis, retinitis pigmentosa, systemic disorders with associated retinal dystrophies, congenital stationary night blindness, cone dystrophies, Stargardt's disease and fundus flavimaculatus, Bests disease, pattern dystrophy of the retinal pigmented epithelium, X-linked retinoschisis, Sorsby's fundus dystrophy, benign concentric maculopathy, Bietti's crystalline dystrophy, pseudoxanthoma elasticum, retinal detachment, macular hole, giant retinal tear, retinal disease associated with tumors, congenital hypertrophy of the RPE, posterior uveal melanoma, choroidal hemangioma, choroidal osteoma, choroidal metastasis, combined hamartoma of the retina and retinal pigmented epithelium, retinoblastoma, vasoproliferative tumors of the ocular fundus, retinal astrocytoma, intraocular lymphoid tumors, punctate inner choroidopathy, acute posterior multifocal placoid pigment epitheliopathy, myopic retinal degeneration and acute retinal pigment epithelitis.
[0036] The preferred forms of the polymeric matrix comprise polymeric microspheres, microparticles, microcapsules, or implants. Even more preferred are polymeric microspheres, microparticles, or microcapsules. Most preferably, polymeric microparticles are used in this invention. The term microparticle refers to any polymeric particle having a diameter or equivalent dimension of about 100 micrometers or smaller.
[0037] Chemically, the polymeric matrix comprises any polymeric material useful in a body of a mammal, whether derived from a natural source or synthetic. While not intending to be limiting, some examples of useful polymeric materials for the purposes of this invention include carbohydrate based polymers such as methylcellulose, carboxymethylcellulose, hydroxymethylcellulose hydroxypropylcellulose, hydroxyethylcellulose, ethyl cellulose and chitosan; and hydroxy acid polyesters such as polylactide-co-glycolide (PLGA), polylactic acid (PLA), and polyglycolide. Other polymers that may be used in the implants of the present invention include polyhydroxybutyric acid, poly(γ-caprolactone); poly(δ-valerolactone), poly(ε-caprolactone), polycaprolactone, hyaluronic acid, thermal gels and polyorthoesters. Preferably, the polymer of this invention comprises polylactide-co-glycolide (PLGA) or polylactic acid (PLA).
[0038] While localized heating is negligible due to very short exposure times at a high dose rate (kGy/sec for β rays it may be desirable to carry out the sterilization step with external cooling.
[0039] The term external cooling refers to the use of cooling source on the polymeric material such that the temperature of the polymeric material is lower at the end of the sterilization process than it would be without the external cooling. External cooling of samples during irradiation is widely practiced in the physical, chemical, and biological arts. For example, x-ray crystallography, nuclear magnetic resonance, fluorescence, infrared, microwave, and other such spectroscopic techniques where the sample is irradiated are routinely carried out with external cooling at temperatures ranging from around room temperature to as low as near 0 K. Furthermore, experiments are routinely carried out by practitioners of the chemical and physical arts where samples are irradiated at temperatures ranging from room temperature down to near 0 K. While not intending to limit the scope of the invention in any way, the cooling source could be a bath of a liquid which is cooled by means of a refrigeration method, a cryogenic liquid or solid, or where the liquid is cooled before use. While not intending to limit the scope of the invention in any way, examples of useful cooling baths include ice water, which can cool to temperatures around 0° C.; a dry ice-organic solvent bath, which can cool to temperatures down to about −77° C.; liquid nitrogen, which can cool to temperatures around 77 K; or liquid helium, which can cool to temperatures of 20 K or lower. Alternatively, the cooling source could cool the entire system comprising the radiation source, the polymeric material, and any auxiliary equipment. In such a case, the cooling source could be a cooled room, a freezer or refrigerator. The cooling source could also be cold air from outdoors on a cold day, which could be pumped in, or alternatively, the sterilization could be done outdoors.
[0040] The temperature of said polymeric material at the end of the sterilization process is about 10° C. to about 50° C. lower than said temperature would be in the absence of external cooling. For example, the temperature of said polymeric material at the end of the sterilization process is about 20° C. to about 50° C. lower than said temperature would be in the absence of external cooling.
[0041] In certain embodiments, the temperature of said polymeric material at the end of the sterilization process is about 50° C. or more lower than said temperature would be in the absence of external cooling.
[0042] In other embodiments, sterilization by irradiation is carried out at a temperature below 25° C. For example, the sterilization by irradiation is carried out at a temperature below about 15° C., more preferably, below about 10° C. In another aspect of this invention the sterilization is carried out at a temperature from −25° C. to 5° C.
[0043] The term irradiation refers to the process of exposing the composites of this invention to a form of radiation. The type and dose of the radiation used in the irradiation process can be determined by one of ordinary skill in the art by considering the type of polymeric material, the type of any therapeutically active agent that may be present, and the use for which the composite is intended. While not intending to limit the scope of invention, in many cases the dose of the radiation would be similar to that used when sterilizing the sample without external cooling. If the cooling apparatus is comprised of a material that would scatter, reflect, absorb, or otherwise decrease the dose of the radiation received by the sample, the dose should be increased accordingly.
[0044] In an aspect of the method of this invention the polymeric material is sterilized by beta irradiation at a dose of about 1.5 to about 4.0 megarads (Mrad), or about 15 kiloGrays (kGy) to about 40 kGy. The polymeric material may be a rod (e.g., extruded filament) or wafer-shaped implant or may be a composition comprising a plurality of biodegradable microspheres. In one embodiment, the polymeric material is sterilized by β-irradiation to a dose of about 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, or 25 kGy, or between about 15 to about 25 kGy.
[0045] In certain embodiments of this invention, the polymeric material is used to accomplish the sustained delivery of the therapeutically active agent. The term sustained delivery refers to the delivery of the therapeutically active agent by a system designed to increase its therapeutic half life relative to an identical therapeutically active agent without such a delivery system.
[0046] In certain embodiments of the method of the present invention the protein is lyophilized with sucrose prior to incorporation into the polymer matrix.
[0047] Lyophilization is a dehydration process which comprises freezing the material(protein) and then reducing the surrounding pressure and adding enough heat to allow the frozen water in the material to sublime directly from the solid phase to the gas phase.
[0048] There are three stages in the complete process: freezing, primary drying, and secondary drying.
[0049] Freezing is done by placing the material in a freeze-drying flask and rotating the flask in a bath, which is cooled by mechanical refrigeration, dry ice and methanol, or liquid nitrogen, or using a freeze-drying machine. In this step, the protein is cooled below its triple point, the lowest temperature at which the solid and liquid phases of the material can coexist to ensure that sublimation rather than melting will occur in the following steps. Larger crystals are easier to freeze-dry. However, the freezing may be done rapidly, in order to lower the material to below its eutectic point quickly, thus avoiding the formation of ice crystals. Usually, the freezing temperatures are between −50° C. and −80° C.
[0050] During the primary drying phase, the pressure is lowered (to the range of a few millibars), and enough heat is supplied to the material for the water to sublimate. The amount of heat necessary can be calculated using the sublimating molecules' latent heat of sublimation. In this initial drying phase, about 95% of the water in the material is sublimated. This phase may be slow, because, if too much heat is added, the material's structure could be altered.
[0051] In this phase, pressure is controlled through the application of partial vacuum. The vacuum speeds sublimation, making it useful as a deliberate drying process. Furthermore, a cold condenser chamber and/or condenser plates provide a surface(s) for the water vapor to re-solidify on to prevent water vapor from reaching the vacuum pump, which could degrade the pump's performance. Condenser temperatures are typically below −50° C.
[0052] It is important to note that, in this range of pressure, the heat is brought mainly by conduction or radiation; the convection effect is considered to be inefficient.
[0053] The secondary drying phase removes unfrozen water molecules, since the ice was removed in the primary drying phase. This part of the freeze-drying process is governed by the material's adsorption isotherms. In this phase, the temperature is raised higher than in the primary drying phase, and can even be above 0° C., to break any physico-chemical interactions that have formed between the water molecules and the frozen material. Usually the pressure is also lowered in this stage to encourage desorption (typically in the range of microbars).
[0054] After the freeze-drying process is complete, the vacuum is broken with an inert gas, such as nitrogen, before the material is sealed.
[0055] At the end of the operation, the final residual water content in the product is extremely low, around 1% to 4%, by weight.
[0056] A person skilled in the art will recognize that there are many ways in which the preferences or embodiments described above can be combined to form unique embodiments. Any combination of the preferences or embodiments mentioned herein which would be obvious to those of ordinary skill in the art are considered to be separate embodiments which fall within the scope of this invention.
[0057] The following U.S. Patent Application Publications are hereby incorporated by reference:
[0058] US 2005/0003007, filed Jul. 2, 2003, and hereby incorporated by reference, discloses a sterilized polymeric material for use in a body of a mammal wherein said polymeric material is sterilized by irradiation at a reduced temperature.
EXAMPLES
[0059] The following example is intended to illustrate the present invention.
Example 1
[0060] Experimental observations are summarized in FIGS. 1 and 2 . SEC-HPLC (size exclusion chromatography) was used to measure the total release of non-aggregated protein. ELISA (enzyme-linked immunosorption assay) was used to monitor the specific binding activity of the released soluble protein in vitro. Under present experimental conditions, a higher cumulative release of soluble, non-aggregated protein or of soluble binding activity is suggestive of less denaturation and less formation of insoluble aggregates within the polymer matrix. The inclusion of the sucrose excipient clearly shows an improvement over the sample containing the glycine excipient and the sample labeled “None”, which does not contain a protective excipient. The sucrose-containing sample also shows an improvement over the sample containing trehelose.
[0061] The present invention is not to be limited in scope by the exemplified embodiments, which are only intended as illustrations of specific aspects of the invention. Various modifications of the invention, in addition to those disclosed herein, will be apparent to those skilled in the art by a careful reading of the specification, including the claims, as originally filed. It is intended that all such modifications will fall within the scope of the appended claims. In particular, although the invention is exemplified by Fab 1211, other proteins having therapeutic use in treating the above-described ocular diseases and conditions may be used in the method and composition of this invention. Moreover, peptides, which are short polymers of amino acids linked by peptide bonds and have the same chemical structure as proteins, but are shorter in length, having therapeutic use in treating the above-described ocular diseases and conditions, may be used in the method and composition of this invention.
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The present invention provides a method for sterilizing a protein-containing bioerodible implant. The sterilization is accomplished using β-radiation, or high energy electrons. Following sterilization the implant can be used in a variety of methods for the sustained release of a therapeutic protein to treat a disease or condition in a human or non-human subject. The sterilization process is compatible with proteins containing one or more disulfide bonds or easily oxidized methionine residues.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to lifting slings as used with invalid lifting devices. The invention also relates to sling/lifting device combinations.
2. Description of the Prior Art
The slings used with invalid lifting devices, particularly invalid hoists, are normally of web form and they have been used in a variety of shapes and sizes to suit lifting requirements and the lifting device employed. In my co-pending patent application Ser. No. 615,301, now abandoned, I have disclosed a lifting method and hoists therefor useable to raise an invalid from a seated to a substantially standing position, employing a lifting sling which passes beneath the arms and around the back of the invalid being lifted. The plain and padded web slings such as have previously been used with invalid hoists possess the disadvantage that they can result in considerable discomfort for the invalid when used with this new lifting method.
SUMMARY OF THE INVENTION
An object of the invention is to provide a sling construction which overcomes the foregoing disadvantage and also provides increased comfort when used in other lifting applications. A further object is to provide sling/hoist combinations advantageously employing such a sling.
According to the invention a lifting sling has end fittings for attachment to an invalid lifting device and is of filled tubular form, comprising an outer sleeve of generally circular cross-section and a resilient filling the resilience of which tends to maintain the normal cross-sectional shape of the outer sleeve.
Thus the invention provides a sling whch in use conforms to the contours of the patient while compressing radially around the back and beneath the arms to a generally elliptical cross-section with rounded upper and lower edges, which result in the sling being comfortable when passed beneath the arms and around the back of an invalid as in the lifting method referred to.
Preferably the outer sleeve is of textile material and it is desirably a woven tubular fabric of synthetic textile material. The use of a woven textile material for the sleeve has important advantages in terms of invalid comfort as such a material has the property of low expansibility under tension. Thus when in use with a sling curved around the back of the invalid the outside of the curved arc of the sling takes the tension during lifting and the inside of the curved arc, which contacts the invalid, remains untensioned and goes slack. Thus the contacting area of the sling loosely conforms to the shape of the invalid against the resilience of the filling and the invalid is cushioned in a very comfortable manner. In fact, the degree of comfort provided is comparable to that achieved with conventional manual lifting in which a human arm is passed around the back of an invalid with the arm muscle conforming to the body shape as a cushion over bone.
Preferably the end fittings of the sling maintain the normal circular cross-section of the sleeve at the ends thereof when the sleeve is tensioned in use. The filling of the sleeve may be provided by a stuffing of material such as KAPOK or a foamed plastic material, the latter conveniently being formed in situ. The end fittings are conveniently plastic moldings which may have apertures through which attachment cord tails extend, these cords being knotted on the inner sides of the fittings for the purpose of retention. The attachment tails have the important advantage that the effective length of the sling, that is the total length of the sling and the tails between the two sling attachment points on the lifting device, is readily adjustable to suit the size of the patient and the lifting procedure, and they also enable the sling to be length adjusted after it has been passed around the patient before lifting is commenced, as will be described hereinafter.
The projecting cord tails may be the two ends of a single cord which passes through the sling, the length of the cord between the retention knots being such that this length remains untensioned when the sling is in use so that it does not affect the comfort of the sling. This arrangement provides the safety feature that should the sling fail, as a result of either failure of the textile sleeve or detachment thereof from an end fitting, the invalid being lifted will still be securely supported by the cord.
In an alternative arrangement separate cords extend from the two end fittings with each cord doubled so that one end thereof can be secured to the lifting device and the other end pulled to tighten the sling around the invalid before it is secured to the hoist. This has the advantage that only half the effort is required to tighten the sling, and each cord may pass around a pulley or through a sheave arrangement on the corresponding end fitting.
The use of a sling with cord tails, which allows the effective length of the sling to be adjusted, has important advantages and is itself a novel concept. It enables the sling to be left permanently attached to the lifting device and adjusted in effective length in a simple manner, without being detached from the lifting device, either before or after positioning around the patient. Thus such a sling/lifting device combination can be usable by a partially disabled invalid, providing a degree of independence not provided by the conventional sling attachment using suspension chains which have to be hooked onto the lifting device, and which have to be detached and hooked on using different chain links in order to adjust the effective length.
Reliable and simple attachment of each end of the outer sleeve to the corresponding end fitting of the sleeve may employ two annular wire rings which surround the sleeve with the end of the latter folded back over the outer ring and threaded back through the inner ring. This requires that each end fitting has a formation, such as an outwardly facing shoulder, over which the inner ring cannot pass while both rings can be loosely threaded over the outer end of the end fitting. With such an arrangement the attachment of the sleeve is a simple manual operation and the fixing is self-retaining in the sense that the greater the tension applied to the sling the more firmly is the sleeve retained at the end fitting. In addition it avoids the stress on a sewn connection which would result if such a connection were to be used.
A sling in accordance with the invention is conveniently used with a lifting method and hoist device in which a single sling is passed beneath the arms and around the back of the invalid while the latter is seated with the lower legs in a substantially vertical position. Such lifting methods and hoists are disclosed in said application Ser. No. 615,301. A lifting arm arrangement to which the sling is attached with the invalid so positioned is pivoted upwardly to raise the invalid to a substantially standing position. The use of the present sling with end attachment tails facilitates initial tensioning of the sling before lifting commences thereby achieving the maximum lift for a given angular movement of the lifting arm arrangement which is typically of the order of 60°. It also has the advantage that there is no requirement to adjust the range or reach of the hoist, all conditions of patient size and height being accommodated by adjustment of the effective sling length. The lifting arms may have end pulleys or guides for the cord tails of a sling in accordance with the present invention, and the latter may be adjustable secured by jamb cleats.
In addition to being advantageously used with a hoist device to raise an invalid from a seated to a substantially standing position, the sling of the invention may with corresponding advantages by used in a sling/hoist combination usable to raise an invalid from a lying down position. Such a combination may operate with a two-stage lift; the first stage of which raises the patient from a lying-down position to a seated position, on a bed for example, and the second stage of which completes the lifting to a substantially standing position.
In a particularly advantageous arrangement the lifting arm arrangement of the hoist or an outer end section thereof, presenting spaced arms to which the lifting tails are attached, is spring loaded upwardly away from its operative lifting position at the commencement of lift. Such an arrangement of the lifting arm arrangement precludes any possibility of the outer arm portions inadvertently striking and injuring the invalid to be lifted during initial positioning of the hoist, and the pre-tensioning of the sling before lifting is commenced overcomes the spring loading of the outer arm section and brings it down to said operative lifting position so that lifting can commence under the control of the lifting mechanism.
Such a hoist arrangement, in which spaced arms to which the lifting sling is attached are in the rest position spring loaded upwardly away from the patient's head and the initial lifting position, is in a preferred embodiment achieved by constructing the arm arrangement with inner and outer arm portions which are articulated with a degree of angular lost motion which allows the spring loaded movement of the outer portion to said rest position and which before lifting commences is taken up against the spring loading by pre-tensioning of the sling. It will be appreciated that the angular lost motion and the associated spring loading can be provided anywhere between an input member which controls lifting movement of the hoist and outer end of the lifting arm arrangement. Thus, for example, the arm arrangement may be a unitary pivotal construction with the lost motion build into the lifting mechanism.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of a sling in accordance with the invention, partly sectioned;
FIG. 2 diagramatically illustrates the combination of the illustrated sling and a hoist arrangement, and the lifting method employed therewith;
FIG. 3 illustrates the attachment of the sling to the hoist arrangement of FIG. 2; and
FIGS. 4 and 5 illustrate a modified hoist construction.
DESCRIPTION OF PREFERRED EMBODIMENTS
The sling S is of stuffed tubular form comprising a woven textile fabric sleeve 1 of a normal circular cross-section attached to identical end fittings 2. The sleeve 1 may be of synthetic plastic material such as nylon or Terylene, and the end fittings 2 are annular plastic moulding with central through bores such as 3. The fittings 2 are molded with an outwardly facing shouder 4 and an adjoining cylindrical peripheral surface 5. The sleeve 1 is secured to each end fitting 2 by two similar annular wire rings 6 and 7 which surround the sleeve 1 and the peripheral surface 5. Both rings 6 and 7 fit loosely over the surface 5, but cannot pass over the shoulder 4. Each end of the sleeve 1, as shown in the sectioned portion of FIG. 1, passes through the corresponding rings 6 and 7, is folded back around the ring 7 and passed back through the ring 6.
The illustrated attachment of the sleeve 1 provides a reliable fixing which is easily performed manually without the use of tools and which is self-retaining. Increase in the tensioning force applied to the sleeve 1 results in firmer retention with each end of the sleeve 1 being more firmly gripped between rings 6 and 7 against the shoulder 4. An attachment cord 8 of the sling which passes through the bores 3 and extends through the sleeve 1 provides projecting end tails 9 for attachment to the lifting hoist. The cord 8 has two knots such as 10 which respectively retain the tails 9 relative to the end fittings 2 as shown in FIG. 1.
The cord 8 extends loosely within the sleeve 1 between the knots 10 so that it does not come under tension when the sling is in use, and the sleeve 1 has a resilient filling 11. The filling 11 may be a material such as KAPOK or a foamed plastic material such as polyurethane. The latter when used may be foamed in situ and injected through one of the bores 3 around the cord 8, with the other bore 3 providing a bleed aperture indicative of complete filling.
FIG. 2 diagramatically illustrates a preferred invalid hoist arrangement utilizing the sling of FIG. 1 and the lifting method employed therewith. The hoist comprises a mobile chassis 20 with castors 21 and an upstanding column 22 supported on the chassis 20. A lifting mechanism 23 mounted at the upper end of the column 22 is manually operated by means of an operating lever 24 which, during a full lifting movement, is moved from the vertical upwardly projecting position illustrated in FIG. 2(a) through an angle of substantially 180° in the direction of the arrow 25. A lifting arm arrangement 26 coupled to the mechanism 23 projects over the chassis 20 and during the lifting movement pivots about a horizontal axis at 27 from the position shown in FIG. 2(a) through an angle of about 60° to the fully-raised position shown in FIG. 2(c).
To lift the seated invalid 1 the hoist is initially brought up to the latter as shown in FIG. 2(a) so that knee abutment means 28 on the column 22 locate against the knees of the invalid 1, the feet of the latter then being placed on a footrest 29 on the chassis 20. As shown the lower legs of the invalid are now substantially vertical. The radius of arcuate movement of the ends of the arms 26 approximates to the average length of the human thigh bone, typically being of the order of 43 cm.
With the hoist located as just described, the support sling S attached to the arms 26 is passed over the head and around the back of the invalid 1 below the arm pits and the projecting tails 9 with the sling S attached to the arm arrangement 26. The arm arrangement 26 comprises an inner arm section 30, and an outer arm section comprising two spaced arms 31 and which pivots relative to the inner arm section 30 about a horizontal axis 32. The arms 31 are spring loaded upwardly about the pivot axis 32 to the free position shown in broken lines in FIG. 2(a). Pre-tensioning of the sling S by pulling on the tails 9 moves the arms 31 downwardly against the spring loading to the limit of their joint pivotal movement relative to the arm section 30 shown in full lines in FIG. 2(a), when the outer arms 31 are effectively an extension of the inner arm section 30. The attachment and securing of the tails 9 to the lifting arms 26 is described hereinafter with particular reference to FIG. 3.
With the sling S pre-tensioned as described the operating lever 24 is pulled down to raise the lifting arms 26 and with them the invalid 1 to the substantially standing position shown as FIG. 2(c). An intermediate position of the invalid 1, at the half-way point in the raising movement, is shown in FIG. 2(b).
FIG. 3 illustrates the arm arrangement 26 and the manner of attachment and securing of the sling tails 9. The inner arm section 30 projects centrally from the pivot axis 27 and is coupled to the lifting mechanism 23, and the outer arm section 33 comprises the two laterally spaced arms 31 to which the sling tails 9 are respectively attached. The spacing of the arms 31 approximates to the shoulder width of a typical invalid, and FIG. 3 illustrates the outer arm section 33 in said free position to which it is moved by said spring loading about the axis 32. A freely rotatable guide pulley 34 is mounted at the outer end of each arm 31, and adjacent the inner end of each arm 31 a jamb cleat 35 is mounted thereon. Each tail 9 terminates in a knob 36 by which it can be pulled to pre-tension the sling S, and by which it is held captive with respect to the corresponding cleat 35 which at the outer end has a guide bore through which the tail passes.
With the hoist initially positioned as has been described and the sling S slackened off the latter is passed around the invalid 1 below the arm pits thereof. The sling S is now pre-tensioned by pulling on the knobs 36, and this pre-tensioning moves the arm portion 33 against its spring loading to take up the angular lost motion with the arms 31 in the initial lifting position illustrated in broken lines in FIG. 3. The sling tails 9 are engaged with the jambing formations of the cleats 35 so that the pre-tensioned sling S is securely attached to the lifting arms 31 and the lifting movement can commence.
FIGS. 4 and 5 illustrate a modified lifting mechanism 123 which incorporates the angular lost motion and associated spring loading which, in the hoist arrangement of FIG. 2, is achieved by use of an articulated lifting arm with the two arm sections 30 and 33 which have been described. A pivotal linkage couples the operating lever 124 to the lifting arm arrangement 126 which is now of unitary constructions, the inner end of the arm arrangement being illustrated in the initial lifting position in FIG. 4 and in the free resting position, to which it is urged by the spring loading, in FIG. 5. The linkage of the mechanism is mounted and shrouded between two spaced cheek plates 100 and the operating lever 124 pivots on a pivot pin 101 fixed between the cheek plates 100, and the unitary lifting arm arrangement 126 pivots on a pivot pin 102 similarly fixed between the plates 100. At its inner end the arm 126 is of generally triangular shape with the pivot 102 adjacent an inner upper apex thereof, and adjacent a lower apex the arm is pivotally attached at 103 to the upper end of a dog-leg link 104. The other end of the link 104 is pivoted at 105 to a protruberence 106 on the lever 124. As so far described the lifting mechanism is identical with the mechanism 23 of FIG. 2, the present modification being concerned with the link 104.
As shown in FIGS. 4 and 5 the upper limb 107 of the link 104 is formed in two relatively telescopic parts. An upper part 107a has a projecting stem 108 slidable in a longitudinal bore 109 in the lower part 107b of the limb 107. A compression spring 110 in the bore 109 urges the two parts 107a and 107b apart to the limb-extended position illustrated in FIG. 5 which provides said rest position of the arm arrangement 126. The initial pre-tensioning of the sling 5 takes up the angular lost motion of the modified arrangement and compresses the limb 107 to its minimum length shown in FIG. 4 and defined by the engagement of abutment faces on the limb parts 107a and 107b at 111 and 112. This defines the initial lifting position of the arm 126.
It is very desirable that a hoist used as has been described with a sling in accordance with the invention should have hand grips which can be held by the invalid while being lifted and supported by the sling. Among other advantages such hand grips contribute to the comfort provided by the sling. In the hoist of FIGS. 4 and 5 such laterally extending hand grips are shown in end view at 127 in these figures. Typical dimensions for the sling S, given by way of example only, are a diameter of 6.5 cm and a length of 93 cm between the attachment rings 6.
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A lifting sling has end fittings for attachment to an invalid lifting device. The sling is of filled tubular form and comprises an outer sleeve of generally circular cross-section and a resilient filling, the resilience of which tends to maintain the normal cross-sectional shape of the sleeve. End tails extend from the fittings for attachment to the lifting device, and the sleeve is a woven tubular fabric of synthetic textile material.
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FIELD OF THE INVENTION
The invention pertains to a small-diameter, light weight coaxial electrical cable having internal crush, torque and kinking resistance.
BACKGROUND OF THE INVENTION
Flexible coaxial cables are frequently used as transmission lines for radio frequency, microwave frequency, and millimeter wave frequency electromagnetic waves. These high frequency waves are capable of carrying many signals simultaneously. Physical maintenance of the signal path is critical to transmitting the signals from one point to another without distortion (return loss) or attenuation (signal loss). The flexible coaxial cables used have an inner conductor of diameter "d" and an outer conductor (shield) of diameter "D". The inner conductor is typically stranded or solid wire and the outer conductor is typically braided metal wire, helically wrapped metal foil, helically-wrapped round wire, or helically wrapped metal-plated or metal-coated polymer. The ratio of the diameter of the inner and outer conductors and the dielectric constant of the material separating them determines cable impedance and must be maintained within tight tolerances. Any distortions due to denting, crushing, or otherwise introducing a non-concentric relationship will result in higher distortion (return loss) and higher attenuation (signal loss). Also, if the integrity of the outer conductor (shield) is interrupted, energy will escape. Torsional (twisting) force can cause the outer conductor to open resulting in an interrupted signal path. The types of damage (denting, crushing, kinking, twisting) described often occur during installation and use due to the cable being bent over sharp objects, clamped too tightly, struck by another object, twisted, or bent beyond its minimum bend radius.
These types of damage are more likely in flexible cables that use air-spaced dielectric materials, but can also occur in cables using solid dielectrics.
In the past, two main approaches have been used to protect cables from crushing and torsional damage. The first is extra layers over the shield of the cable such as braided wires and/or hard-film wraps such as Kapton® polyimide and thicker external jackets. These tend to be very stiff. The second approach is the use of external means of providing added protection in the form of flexible conduits. Typical examples would be springs covered with extruded polymers or shrink tubes and flexible metal conduits (armors). The external conduit or ruggedizations such as shown in U.S. Pat. No. 4,731,502, while adding significant crush and/or torque resistance, add significantly to the weight and diameter of the cable.
SUMMARY OF THE INVENTION
This employs an internal mechanical means for greatly increasing the crush, kinking, and torque resistance of a coaxial transmission line. The transmission line of the invention comprises a coaxial transmission line having a closely-spaced spirally wrapped rigid wire over the outer conductor of the transmission line and under the polymeric protective outer jacket of the line. This provides crush and kinking resistance. The addition of a braided wire, fiber, or tape layer over the spirally wrapped rigid wire provides torque resistance as well. An extruded or tape-wrapped polymer separator layer may be utilized to separate the outer conductor of the line from the spirally-wrapped rigid wire or between the rigid wire and a layer of mechanical braid to provide flexibility to the cable.
The coaxial cable of the invention provides considerable crush, kinking, and torque resistance. As a result, the electrical performance of the transmission line is maintained under harsher environments of installation and use and the useful life of the transmission line is greatly extended. These improvements are provided while maintaining a high degree of flexibility and minimum spring-back in the cable. The diameter and weight of the cable is considerably less than that obtained by external means of protection.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a side view of a cable of the invention with the layers cut away for display.
FIG. 2 is a peeled back side view of an alternative cable of the invention.
FIG. 3 is a peeled back side view of another alternative cable of the invention.
FIG. 4 is a peeled back side view of yet another alternative cable of the invention.
DESCRIPTION OF THE INVENTION
The cable of the invention is described now with reference to the drawings to more carefully and completely delineate the invention. The invention provides a coaxial cable in which a strong, rigid wire 6 is closely spiralled at a relatively steep angle of lay, such as 45° or greater from the axis of the cable, preferably 60° or greater around the coaxial transmission line, outside of the outer conductor 3 or shield of the basic coaxial transmission line, but inside a protective plastic outer jacket 8. One or more layers of mechanical braid 4 or 7 of metal or strong polymer fiber are applied either or both inside and/or outside the spiralled rigid wire 6, over the coaxial transmission line, but inside the outer protective polymer jacket 8. A plastic separator 5 may optionally be applied between spiral wire 6 and mechanical braid 4 or outer conductor 3 of the coaxial transmission line. Separator 5 aids in movement of the layers and flexibility of the over-all cable when it is flexed or bent in installation or use.
FIG. 1 describes a side view of a cable of the invention with the layers partially removed for easy viewing of the internal structure of the cable. Center conductor 1 of the transmission line is an electrically conductive metal signal-transmitting wire covered with at least one layer of electric insulating material 2 which may be extruded onto conductor 1 or spirally or helically wrapped about conductor 1 if a plastic tape is used for insulation 2. An outer electrical conductor 3 is placed about insulation 2 by methods and processes well-known in the art for that purpose. A mechanical braid 4 is next braided around the basic coaxial signal transmission line described above. Braid 4 may be formed from round or flat metal wire or tape or a strong plastic fiber. Over braid 4 is extruded or helically or spirally wrapped a plastic separator 5, which lies under and separates from braid 4 a layer 6 of rigid closely-spaced spirally or helically wrapped wire at a relatively steep angle (45°-65° or greater to the cable axis) with the coils thereof close together but separated from each other. The spacing of the coils may be varied from being in contact to being separated to provide greater crush resistance or greater flexibility. At least a small space between the coils is preferred for flexibility while retaining maximum crush resistance. Placing the spiral wires close together provides a bend radius limiting mechanism, i.e. resists kinking. Layer 6 of rigid wire provides excellent crush resistance to the transmission line. Next comes a layer 7 of tightly woven mechanical braid of the same or similar alternative materials to braid 4. This adds torque resistance to the transmission line. The cable is completed by applying a protective plastic outer jacket 8 onto it by extrusion or tape wrapping, for example.
As to the materials found useful in manufacture of the transmission line of the invention, center conductor 1 preferably comprises a copper, silver-plated copper, or silver-plated copper-clad steel wire. Insulating or dielectric material 2 is preferably porous or solid polytetrafluoroethylene (PTFE), polyethylene, or fluorinated ethylene-propylene copolymer (FEP). Outer conductor 3 of the basic coaxial cable is a material containing electrically conductive metal, such as for example round or flat wire braid, helically or spirally wrapped metal-coated polymer tape layers, helically wrapped metal foil, and served metal wire. The round wire braid is preferably made of silver-plated copper or silver-plated copper-clad steel wire. A flat wire braid is preferably formed from silver-plated copper tape. An aluminized polyimide tape, such as Kapton® tape, or polyester tape, such as Mylar® is preferred for a helically wrapped metallized polymer tape. Optional mechanical braid 4 is preferably formed from silver-plated copper, silver-plated copper-clad stainless steel, or stainless steel wires or strands or from strong aromatic polyamide plastic fibers or strands, such as for example Nomex® or Kevlar® fiber.
The optional separator 5 is a plastic sheath, either extruded or tape-wrapped around either outer conductor 3 or mechanical braid 4, but under spiral wire 6. Useful materials for separator 5 include extruded PTFE, FEP, silicone, polyethylene and polyperfluoroalkoxy tetrafluoroethylene (PFA), and tape-wrapped porous PTFE tape, polyester tape, and polyimide tapes, for example.
Rigid Spiral wire 6, which serves to ruggedize the transmission line by increasing the crush and torque resistance (in one direction) of the line and increasing the resistance to kinking, is preferably made of stainless steel, phosphor bronze, silver-plated copper-clad steel, or similar hard materials. Wire 6 may be a single end of wire or a group of parallel wires. Wire 6 is applied at a relatively steep angle of lay in closely spaced spirals to maximize crush resistance and resistance to kinking.
To control the effects of torque on the transmission line, a layer of mechanical braid 7 is braided over hard wire spiral 6. The materials useful for this braid are the same as those listed above for braid 4.
To protect the transmission line from the environment, an outer jacket 8 surrounds braid 7 or spiral 6 to encase the line. Jacket 8 may be extruded over the cable or applied by other means and may be omitted. Suitable materials useful for jacket 8 include PTFE, FEP, PFA, polyvinyl chloride, and polyurethane, for example. Separator layer 5 may also be used to provide environmental protection to the transmission line.
FIG. 2 shows a side view of an alternative embodiment of the cable of the invention wherein an optional mechanical braid 4 has not been included.
FIG. 3 describes a side view of another alternative embodiment of the cable in which there is no intervening mechanical braid 7 between spiral 6 and jacket 8.
FIG. 4 depicts a side view of yet another alternate embodiment of the cable wherein an optional plastic separator 5 has not been included, but mechanical braids 4 and 7 have been applied on each side of rigid spiral wire 6.
The above materials and construction provide a transmission line having crush, kinking, and torque resistance (except FIG. 3). The cable remains curved when once bent (does not tend to spring back). The diameter of the cable is smaller than that attainable by external methods of ruggedization, the weight is equal or less, and a smaller bend radius is possible. The cable resists being bent to the point of kinking and retains its concentricity on bending better than non-ruggedized coaxial cables. The crush resistance is superior to other internal forms of ruggedization.
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A crush, kink, and torque resistant, flexible coaxial cable having a closely spaced, spiralled rigid metal wire layer between the outer conductor of the coaxial transmission line and the outer jacket of the cable. Small size light weight, good flexibility with minimum spring-back and excellent crush resistance are provided together with excellent kinking, and torque resistance. This eliminates the need for external ruggedization to protect the electrical properties of the cable.
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This is a national stage of PCT/MX10/000075 filed Aug. 6, 2010 and published in Spanish, which claims the priority of Mexican number MX/a/2009/008453 filed Aug. 7, 2009, hereby incorporated by reference.
TECHNICAL FIELD
The present invention refers to the new Escherichia coli strains denominated JU15, JU15A, LL26 and MS04 deposited in the Agricultural Research Service (ARS) patent Culture Collection (NRRL) of the Agricultural department of the United States, with access numbers NRRL B-50140, NRRL B-50137, NRRL B-50139 and NRRL B-50138, and their derivatives that produce metabolites, particularly D-lactate, L-lactate or ethanol, with high yield and selectivity from a wide variety of carbon sources. These sources include media formulated with hydrolyzed vegetables, such as sugarcane bagasse, agave bagasse and fast-growing grasses; a wide variety of agro-industrial wastes, such as whey or forestry waste, cellulose, grasses, agave bagasse, paper waste, shavings and sawdust; shrubs and generally any material derived from lignocellulose; glycerol derived from biodiesel production; and sugars derived from starch and sucrose. Through the use of the strains of E. coli referenced above, these sources are used in the production of the metabolites of interest (especially D-lactate, L-lactate or ethanol) as the only way to regenerate the reducing power. The invention also refers to the fermentation methods to produce these metabolites from media with different carbon sources, including glucose, lactose or xylose.
BACKGROUND OF THE INVENTION
In recent years, the use of recombinant DNA technology and the systematic analysis of biological data have increased considerably, yielding Metabolic Pathway Engineering (MPE), which is defined as the modification and/or introduction of new biochemical reactions for the direct improvement of cellular properties through recombinant DNA technology (Stephanopoulos, 1999; Bailey, 1991). Specifically, new strains are now being developed through MPE that have the property of being able to grow in mineral media and to produce primarily a single microbial metabolite—for example, only one lactate isomer (Bai et al. 2003; Dien et al., 2002; Zhou et al. 2003a and 2003b; Zhu and Shimizu 2004; Zhou et al., 2006a; Zhou et al. 2006b; Zhou et al., 2005).
Lactic Acid.
In the chemical industry, especially in the manufacturing of raw materials for the production of plastics of biological origin, the biotechnological production of lactic acid has attracted a large amount of interest recently, as this compound offers a sustainable alternative for the manufacturing of high-quality biodegradable plastics known by the generic name of polylactates (PLAs); examples include polylactate and ethyl-lactate (Dien et al., 2002; Skory, 2003). The synthesis of biodegradable PLAs requires the separate production of the D and L lactate isomers. In addition, the physical and biodegradative properties of PLA depend on the proportion of the D and L forms used in the synthesis of the polymer. Lactate can be produced by microbial fermentation or by chemical synthesis (Narayanan et al., 2004). The most commonly used chemical process is the hydrolysis of lactonitrile with strong acids; however, there are other chemical routes (John et al., 2007), such as the oxidation of propylene glycol, the reaction of acetaldehyde with carbon monoxide and water at high temperatures and the hydrolysis of chloropropionic acid, among others. All of these routes yield a mixture of D and L isomers as a final product and depend on raw materials derived from petroleum, which makes these production processes less sustainable. In contrast, the biotechnological production of lactic acid has several advantages over chemical synthesis: 1) the low cost of the substrates, 2) the low production temperature, 3) the low energy consumption and 4) the specificity for the desired stereoisomer. The lactate is produced through a process of microbial fermentation of culture media with an easily assimilated carbon source, such as glucose.
Ethanol
One of the most difficult challenges in the present search for substitutes for fuels derived from petroleum is the identification of possible alternative liquid fuels.
The production of ethanol from biomass is one of the few currently viable options (Mielenz, 2001). Several technologies are in the growth stage; a large variety of raw materials can be used; and the ethanol produced is a valuable and versatile compound, as it can be used as an oxygenating agent, fuel or solvent or be transformed, using established technologies, into other fuels (e.g., biodiesel) (Bungay, 2004).
Ethanol can be used for many applications. The primary application discussed in this document is as a liquid fuel that will oxygenate, substitute for or complement fossil fuels that are currently used in internal combustion engines. Other applications of ethanol include its use as a fuel in industrial boilers, lamps, furnaces, turbines, among others.
When compared in volumetric terms, the energetic content of ethanol is approximately two-thirds of that stored in gasoline or diesel. However, ethanol has a high octane value, which causes the engines that use gasoline-ethanol mixtures to have a better efficiency. Mixtures that contain up to 22% (v/v) ethanol can be used successfully in current gasoline engines, that is, without the need of modifying these internal combustion engines.
Another alternative use of ethanol is as an oxygenating agent. To improve combustion and to reduce the levels of carbon monoxide produced, fuels need to elevate their octane value without using lead. To that end, alcohols and esters have been used. Currently, in Mexico, tert-butyl ethers are used, of which methyl tert-butyl ether (MTBE) is the most commonly used. However, it is known today that these compounds can accumulate in groundwater, are resistant to chemical and biological degradation and are carcinogenic to humans in parts per million concentrations. In several states, such as California, their use has been prohibited.
Traditionally, ethanol is obtained through the fermentation of glucose or sucrose, which are obtained from corn starch and cane sugar, respectively. This fermentation is conducted using ethanol-generating organisms, such as Saccharomyces cerevisiae . This organism is traditionally used for the production of ethanol from glucose, which is generated from the hydrolysis of grain starch and sucrose obtained from cane sugar or sugar beet. This microorganism does not have the ability to metabolize the five-carbon sugars, known as pentoses that are abundantly found in hydrolyzed vegetable material (Hahn-Hagerdal of al., 1993). Another ethanol-generating organism is Zymomonas mobilis , a Gram-negative bacterium, which has the native ability to produce a good yield of ethanol due to its metabolic characteristics. Among these characteristics are two very efficient enzymatic activities, those of pyruvate decarboxylase (Pdc) and alcohol dehydrogenase (Adh), which convert pyruvate into acetaldehyde and ethanol, respectively. However, as also occurs with S. cerevisiae, Z. mobilis is limited in the sugars that it can metabolize. This organism can only use sucrose, glucose and fructose, and it does not use xylose, other pentoses or other disaccharides.
Carbon Sources
Glucose
Cellulose is the greatest component of lignocellulose (20-50%). It is a linear polymer composed of dextrose subunits (D-glucose) that are joined by glycosidic bonds β-(1-4), and due to its structural conformation, it is highly resistant to hydrolysis. To take advantage of cellulose, it is necessary to hydrolyze it with cellulases. The hydrolysis of cellulose yields glucose, which is fermentable by the strains mentioned in the present invention. Glucose is primarily obtained from the hydrolysis of starch
Xylose and Other Monomers
In contrast to cellulose, hemicellulose is not chemically homogeneous, as it is a heterogeneous polysaccharide that contains hexose monomers (glucose, mannose and galactose), pentose monomers (xylose and arabinose) and several acids (acetic acid and glucuronic acid). This composition increases the difficulty of the bioconversion of hemicellulose to fermentation products that are of interest for industrial use. In addition, hemicellulose is the second most common polysaccharide in nature, as it represents 20-35% of the cell mass of lignocellulose. The proportions of pentoses and hexoses in hemicellulose are 85 and 15%, respectively, where xylose is the most abundant, followed by glucose and arabinose (75, 15 and 10%, respectively) (Saha, 2003). Hemicellulose can be converted into monomeric sugars through the use of hydrolysis at temperatures below 200° C. using low acid concentrations, although there are several hydrolysis methods: physical, physicochemical, chemical and/or biological (Sun et al., 2002).
Thus, it can be concluded that, excepting glucose, xylose is the most abundant monosaccharide in nature and is generally found polymerized in the hemicellulose fraction of the vegetable tissue. However, the variety of microorganisms that metabolize both pentoses and hexoses is very limited. Furthermore, there are no wild microorganisms that can efficiently catabolize pentoses or mixtures of pentoses and hexoses through fermentation processes into products of industrial interest at high yields (Hernández-Montalvo et al., 2001).
Therefore, the conversion of lignocellulose materials has serious limiting factors, as these materials are composed of sugar polymers, primarily glucose and xylose; xylose is a pentose that is not fermentable by most of the wild or genetically modified microorganisms used in industry, such as Saccharomyces cerevisiae, Corynebacterium glutamicum , certain lactobacilli, Zymomonas mobilis or Bacillus subtillis (Dien et al., 2001). Another disadvantage for the industrial use of lignocellulose materials is that the majority of microorganisms used to this end, such as lactobacilli, require complex culture media, thus increasing the costs of production because of the need for nutrients, product purification, etc. In addition, in the case of lactic acid, most of the microorganisms synthesize only the D-lactic isomer or a mixture of D and L-lactic.
Lactose
Lactose is a disaccharide made up of glucose and galactose molecules joined by a beta 1-4 link. This disaccharide is found in mammalian milk, and it is common to find it in whey as an agro-industrial residue obtained in cheese production.
Escherichia coli
Among the microorganisms used industrially for the production of D-lactate, species from the genera Lactobacillus, Rhizopus and Escherichia are most commonly used. Of these microorganisms, Escherichia coli have several advantageous characteristics as the base microorganism for the development of strains and for the production of biotechnology products. Among these characteristics are the following: it grows rapidly under aerobic or anaerobic conditions, its complete genome is known, methodologies are available to modify its genome, and it can metabolize both hexoses and pentoses, as well as disaccharides and a wide variety of other sugars and carbon sources, using only mineral salts as nutrients. For this reason, the strategies of metabolic engineering propose changes in the fermentation pathways to modify the balance of carbon toward the desired product, maintaining the redox balance and preventing the formation of subproducts, with the goal of improving the accumulation of a single fermentation product. For example, if the end product is lactic acid (Zhu et al., 2007), a homolactic microorganism is obtained, whereas, if only ethanol is produced, the microorganism is homoethanologenic (Zhou et al., 2008).
According to the functional metabolic network of E. coli in fermentation conditions, for each mole of glucose (Glc) that is catabolized to pyruvate, two moles of ATP are obtained. If half of the pyruvate generated is converted into acetic acid, the yield increases to 3 mol ATP /mol Glc . However, in the case of xylose (Xyl), the yield is only 0.67 mol ATP /mol Xyl when E. coli catabolizes this sugar into pyruvate. This value is so low that the enzymes pyruvate formate lyase (Pfl) and acetate kinase (Ack) are essential in the growth of E. coli from xylose in fermentation conditions, as the conversion of one mole of pyruvate into acetyl-CoA and, in turn, into acetate generates one extra mole of ATP, increasing the yield of ATP to 1.5 mol ATP /mol Xyl . As a consequence, the E. coli W3110 strains without pflB cannot grow in pentose, as they only yield 0.67 mol ATP /mol Xyl . The insufficiency of ATP was confirmed by inactivating the acetate kinase (ack) gene in E. coli W3110. This mutant was incapable of growing in the minimal media supplemented with xylose in anaerobic conditions, verifying the need for the ATP produced by Ack (Hasona et al., 2004). For glucose, the transport and phosphorylation is carried out by the PTS system, with an equivalent cost of ATP. In contrast, for xylose, the cell spends two molecules of ATP, one for the transport (high-affinity ABC transporter) and the second for phosphorylation (Lin, 1996; Linton and Higgins 1998). In arabinose, the internalization of the pentose in the cell is carried out by symport (arabinose/H + ) through AraE, a low- and high-affinity transporter. This approach conserves one molecule of ATP spent in the transport of pentoses through the ABC transporter, and both mutants (pfl and ack) grow in arabinose (Hasona et al., 2004).
The Use of E. coli in the Production of Lactic Acid
For the production of lactic acid, E. coli has a gene that codes for an enzyme vital to lactate production, lactate dehydrogenase (IdhA), which is expressed in anaerobic conditions (Zhou et al., 2003a). However, when grown in the presence of glucose or xylose, E. coli is heterofermentative, yielding acetic, formic, lactic and succinic acids, in addition to ethanol, hydrogen and carbon dioxide (Bock and Sawers 1996). Through MPE techniques, E. coli strains have been modified by the blockade of pathways that compete for pyruvate availability to induce the microorganism to become homofermentative and mostly produce D-lactate (U.S. Patent Application No US2007/0037265) from pyruvate; however, those strains were modified to use only glucose as a carbon source and to produce D-lactate, with high conversion yields. In contrast, there are reports that detail the inability of E. coli strains that produce D-lactate to grow using xylose as the main source of carbon, due to the low yield of ATP that is obtained with this sugar (Hasona et al., 2004).
The most commonly used strategy for the generation of E. coli strains that produce high optical purity D-lactate consists of suppressing the gene that codes for the pyruvate formate lyase activating enzyme (pflB) (Zhou et al., 2003a and 2003b; Zhu and Shimizu 2004; Zhou et al. 2006a; Zhou et al., 2006b; Zhou et al., 2005). This strategy has yielded conversion efficiencies of the carbon source into D-lactate above the theoretical 95% value (Zhou et al., 2003a and 2003b) but has restricted the industrial process to use glucose as the only carbon source. Another disadvantage comes as a response to a low availability of acetyl-CoA (a key metabolite in the contribution of carbon backbone to cell mass), yielding strains with a very low or null growth rate in anaerobic growth conditions or with glucose as the only carbon source. Typically, these strains are incapable of growing unless the media is supplemented with acetate (Zhou et al., 2003a), driving up the price of the culture media and/or complicating the industrial process.
The Use of E. coli in the Production of Organic Acids and Ethanol
In contrast, E. coli has a pathway to produce other compounds of industrial interest, such as ethanol, in a natural fashion. However, the amount of alcohol that is produced in this manner is very low. In addition to the product of interest, a mixture of other fermentation products is produced, among which are acetic, formic, succinic and lactic acids (Gonzalez et al., 2002; Dien et al., 2003; Lawford and Rousseau 1996; Lawford and Rousseau, 1997); thus, the microorganism is heterofermentative. With the use of Metabolic Pathway Engineering (MPE), the flow of carbon has been redirected to a heterologous ethanol production pathway in E. coli , yielding strains with a different genetic background from those reported in the present invention that are capable of providing good yields in the fermentation of glucose or xylose to ethanol (Otha et al., 1991).
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 . Image that shows the inactivated pathways in the glucose and xylose metabolic network of E. coli ; and the main fermentation products, including the ATP, in CL3 strain.
FIG. 2 . Image that shows the inactivated pathways in the glucose and xylose metabolic network of E. coli ; and the main fermentation products, including the ATP, in JU15 strain.
FIG. 3 . Image that shows the inactivated pathways in the glucose and xylose metabolic network of E. coli ; and the main fermentation products, including the ATP, in JU15A strain.
FIG. 4 . Image that shows an agarose gel with the PCR products of possible ΔpflB. Mutants (Lane heading represents the colony number) (C: control). Lanes 12, 15, 17, 18 product corresponds to the size of the inactivated gene. Lanes 13, 14, and 16 corresponds to the size of the intact gene. The numbers represent the size of the product in base pairs.
FIG. 5 . Illustrates the production of: A) Lactic acid and B) Acetic acid of the selected colonies (12, 15, 17, 18, 25, 26, 46), as well as W3110 pfl − and MG1655 strains.
FIG. 6 . Illustrates the production of: A) Formic acid and B) Ethanol of the selected colonies (12, 15, 17, 18, 25, 26, 46), as well as W3110 pfl − and MG1655 strains.
FIG. 7 . Picture that shows an agarose gel with a 1.9 Kbp PCR product that corresponds to the inactivated adhE gene. The numbers represent the size of the product in base pairs.
FIG. 8 . Graphics that show a comparison of strains CL3 and CL1 in their: A) Growth rate and B) xylose consumption kinetics.
FIG. 9 . Graphics that show a comparison of strains CL3 and CL1 in their: A) Growth and B) lactate production kinetics.
FIG. 10 . Picture that shows an agarose gel with a PCR product that corresponds to the inactivated xylFGH genes.
FIG. 11 . Growth kinetics of strains JU01 and CL3 in xylose 40 g/L AM2 medium
FIG. 12 . Graphic that shows: I) the growth kinetics during the adaptive evolution of strain JU01 in 120 g/L xylose AM2 medium and II) a bar graphic that show the organic acid productivity at 48 h.
FIG. 13 . Illustrates the effect of the pH in the growth of strain JU15.
FIG. 14 . Growth kinetics of E. coli strain JU15 on simulated hydrolysate 1.
FIG. 15 . Growth kinetics of E. coli strains JU15 and JU15A on simulated hydrolysates.
FIG. 16 . Growth kinetics of E. coli strain JU15A on simulated hydrolysate 1.
FIG. 17 . Graphic that shows the growth and substrate consumption kinetics of JU15A strain on simulated hydrolysates 1
FIG. 18 . Fermentation kinetics of strain JU15A on simulated hydrolysate 2.
FIG. 19 . Graphic that shows the growth and substrate consumption kinetics of strain JU15A on simulated hydrolysate 2
FIG. 20 . Graphics that show: I) growth kinetics and II) lactate production kinetics on sugarcane bagasse hydrolysates of 6 independent experiments (A, B, C, D, E, F) using E. coli strain JU15A.
FIG. 21 . Graphics that show kinetics of: I) glucose consumption and II) xylose consumption on sugarcane bagasse hydrolysates of 6 independent experiments (A, B, C, D, E, F) using E. coli strain JU15A.
FIG. 22 . Graphics that show kinetics of: I) arabinose consumption II) acetic acid accumulation on sugarcane bagasse hydrolysates of 6 independent experiments (A, B, C, D, E, F) using E. coli strain JU15A.
FIG. 23 . Fermentation kinetics of strain JU15A on sugarcane bagasse hydrolysates.
FIG. 24 . Lactose consumption kinetics of three different strains: MG1655, JU01 and JU15
FIG. 25 . Graphic that shows D-lactate production kinetics from lactose of three different strains: MG1655, JU01 and JU15.
FIG. 26 . Graphic that shows base consumption kinetics in three different media with milk whey using JU15 strain.
FIG. 27 . Image that shows the pLDHBsC plasmid carring the gene LDH Bs , the P1, FRT sites; the chloramphenicol acetyl transferase gene; and the FRT and P2 sites.
FIG. 28 . Image that shows an agarose gel with a PCR product corresponding to the integration of the heterologous gene. Lane 1: Molecular weight marker (size in base pairs); Lanes 2 and 3: 2.6 kbp PCR products corresponding to the verification of the gen in the LL1 strain.
FIG. 29 . Image that shows an agarose gel with the verification of the heterologous gene integration and the elimination of the chloramphenicol acetyl transferase gene. The PCR products of the colonies with the inactivated IdhA gene and without the Cm resistance gene are showed in the 2-6 lanes, as well as the control strain JU15 in the 7 and 9 lanes which product is 1069 by size. The 8 lane is the negative control of 1860 by size.
FIG. 30 . Illustrates the adaptive evolution and the KOH 2N consumption of the strains LL2 vs strain JU15 in xylose 40 g/L.
FIG. 31 . Image that shows a 1% agarose gel with the PCR product of the chloramphenicol acetyl transferase gene (Cm), flanked by the FRT, PS1 and PS2 sites; and the JU15A IdhA gene homology sequences. Lane 1: molecular weight marker (size in bp), lane 3: PCR product.
FIG. 32 . Image that shows a 1% agarose gel with the verification of the IdhA gene inactivation by PCR. Lane 1: molecular weight marker (size in bp), lane 3: control Cm R , Lanes 4-7: PCR product of 4 colonies transformed with an oligonucleotide with homology to the Cm gene region and the oligonucleootide 1190 RVF.
FIG. 33 . Image that shows a 1% agarose gel: Lane 1-2 molecular weight marker (size in bp); Lane 3-6 PCR product showing the inactivation of the IdhA gene and the elimination of the Cm gene from 4 colonies transformed with the pCP20 plasmid, product size: 619 bp; Lane 7: control strain JU15A IdhA + (1482 bp).
FIG. 34 . Image that shows an agarose gel with a PCR product that carries the pdc and adhB genes from Z. mobilis flanked by homology sequences up and downstream from pflB gen of E. coli strain MS01. Lane 1: molecular weight marker (size in bp), lane 2: PCR product.
FIG. 35 . Image that shows an agarose gel with a PCR product with oligonucleotides 250 bp up and downstream of pflB gen. Lane 1: molecular weight marker (size in bp), Lanes 2 and 9: control strain MS01; 569 pb, and lanes 3-8: PCR product resulting of the integration of pdc and adhB genes from Z. mobilis under the promoter of pflB: 3361 bp.
FIG. 36 . Graphic that shows the fermentation kinetics of the strain E. coli MS01 in AM2 medium with A) glucose and B) xylose (50 g/L), all of them with acetate (2.05 g/L)
FIG. 37 . Graphic that shows the fermentation kinetics of the strain E. coli MS04 in AM2 medium with glucose-xylose mixture (7.5-42.5 g/L) and acetate (2.05 g/L).
FIG. 38 . Graphic that shows: I) the fermentation kinetics of the strain E. coli LL26 in AM2 medium with glucose (4%). II) Glucose consumption and lactate production. The yield was close to the theoretical (100%) and the volumetric productivity 1.17 g of lactate per liter per hour.
FIG. 39 . Graphic that shows: I) the fermentation kinetics of the strain E. coli LL26 in AM2 medium with xylose (4%). II) Xylose consumption and lactate production. The yield was close to the theoretical (100%) and the volumetric productivity 0.68 g of lactate per liter per hour.
FIG. 40 . Image that shows the inactivated pathways in the glucose and xylose metabolic network of E. coli ; and the main fermentation products, including the ATP, in strain LL26.
FIG. 41 . Image that shows the inactivated pathways in the glucose and xylose metabolic network of E. coli ; and the main fermentation products, including the ATP, in strain MS04.
FIG. 42 . Ethanol production kinetics using hydrolysate syrups from the grass Paspalum fasciculatum.
FIG. 43 . Ethanol production kinetics using hydrolysate syrups from agave bagasse ( Agave tequilana ).
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, through the use of a Metabolic Pathway Engineering (MPE) original design and adaptive evolution, E. coli strains capable of growing with different basic carbon sources, such as glucose, xylose, arabinose and/or lactose, among others, are used to convert the carbon source into a single metabolite of interest, particularly L-lactate, D-lactate or even ethanol, with high productivity and yield. The starting material was a homolactic strain that showed superior abilities in terms of the specific growth rate, glucose consumption and D-lactate production compared with the E. coli strains previously reported. The E. coli strain named in the present invention as strain JU15, which has been deposited in the ARS Patent Culture Collection (NRRL) of the U.S. Department of Agriculture with access number NRRL B-50140, is capable of fermenting sources that are difficult to assimilate, such as hydrolysates of the hemicellulose fraction of vegetable tissues (abundance of xylose), including sugar cane bagasse, and of producing D-lactate with a yield of 95% of the theoretical value, with velocities comparable to that of lactic acid bacteria (strains commonly used to produce D-lactate).
In a time when the planet is experiencing climate change, which is a consequence of an indiscriminate use of ‘dirty’ technologies that consume finite raw materials, there is a need to develop sustainable technologies that are capable of producing intermediate raw materials for the chemical, pharmaceutical, petrochemical or processing industries that will allow the substitution of grains or seeds (which are the basis for the processing of industrialized cereals, sweeteners, bread, tortillas, etc., and are of critical importance to human sustenance) for petroleum derivatives (finite and continuously increasing in price). In addition, there is the opportunity to use the abundant agro-industrial resources or vegetable tissues, which are currently underused in the best of cases and which can be significant pollution sources in the worst-case scenario. However, as has been mentioned before, few microorganisms found in nature are able to grow and produce metabolites of industrial interest from less conventional sugars, such as xylose, the second most abundant monosaccharide in nature (although in its polymerized form), or lactose, a residual disaccharide of the milk product industry. Thus, a technical problem is identified that consists of constructing strains for industrial use that efficiently and preferentially produce metabolites of industrial interest, starting not only from glucose but also from less conventional sugars, such as xylose and lactose; from other carbohydrates; and even from high concentrations of acetic acid.
The developers of the present invention, seeking to propose a solution to that technical problem, have generated new microbial strains that are capable of growing and fermenting glucose. However, most importantly, these strains can also use xylose and even lactose efficiently, converting these carbon sources into a single metabolite of industrial interest. Among the metabolites that can be produced with the strains in the present invention are the acetic, succinic, malic, pyruvic and lactic organic acids, with the last being produced as either the D or L isomer with a high degree of optical purity. Other possible metabolites include alcohols, such as ethanol or 1,2- and 1,3-propanediol, among others. To achieve this end, the inventors used the most recent techniques of metabolic pathway engineering, following original criteria.
In another aspect, the present invention refers to methods or processes to bioconvert sugars into metabolites of industrial interest through the use of the strains of the present invention. With these methods, the sugars present in vegetable tissues, such as sugar cane bagasse, are converted into different metabolites of industrial interest, such as D and L-lactate with yields on the order of 95% and volumetric productivities of approximately 1 g/(L*h) and ethanol with a 90% yield and 1 g/(L*h) productivity. A great advantage of the methods of the present invention is that the yield of such metabolites can be obtained through fermentation in a simple and cheap medium using the sugars found, for example, in hydrolysates of the hemicellulose fraction of vegetable tissues, such as sugar cane bagasse, or in agro-industrial residues, such as whey, and resulting in high yield and productivity. These strains are compared with other strains of E. coli previously reported that do not efficiently metabolize xylose and that require complex media to grow.
The present invention yielded several bacterial strains that were genetically modified in an incremental fashion so that lactate production is the only major pathway for the regeneration of reducing power. Among these strains is the modified recombinant strain CL3 (Utrilla et al., 2009), with the genes pflB, adhE and frd suppressed to stimulate the homofermentative production of D-lactate (see FIG. 1 ); this strain shows superior abilities in terms of the specific growth rate, specific glucose consumption rate and specific D-lactate production rate relative to the strains previously reported. In contrast to the strains previously reported, this strain is capable of growing efficiently at a specific rate of 0.22 h −1 in a simple mineral medium formulated with glucose as the only carbon source. This strain shows a 95% conversion yield of glucose to D-lactate at a specific velocity of glucose consumption of 6 g/(g cells*h). Additionally, as a result of this strain's unusual ability of growing at densities of approximately 1 g/L, it has the highest volumetric productivity of D-lactate achieved in a culture of an unevolved strain. Because of the characteristics previously mentioned, this strain was used as a starting point for subsequent modifications for the efficient metabolism of xylose and the production of other metabolites. The unprecedented ability of the CL3 strain to grow optimally in anaerobic conditions was considered to be a key ability for use as a starting point for the development of the present invention.
This CL3 strain was used as the starting point for subsequent modification and to achieve the efficient conversion of xylose into lactate, for which modifications to xylose transport were performed, inactivating the ATP-dependent transporter (xylFGH) (see FIG. 2 ) and subjecting this bacterial strain to a process of adaptive evolution in mineral media (AM2) with 12% xylose. This process yielded the new strain labeled in the present invention as JU15 (deposited in the ARS Patent Culture Collection (NRRL) of the U.S. Department of Agriculture with access number NRRL B-50140). Through a second process of adaptive evolution, using medium with both xylose and acetate to prevent growth inhibition by acetate, a derivative strain named JU15A was obtained (see the diagram of its metabolism in FIG. 3 ) (deposited in the ARS Patent Culture Collection (NRRL) of the U.S. Department of Agriculture with access number NRRL B-50137). In contrast to previous stains, JU15A is capable of growing even in culture media with high acetate concentrations, even those greater than 15 g/L, which is the acetate concentration that is found in vegetable hydrolysates, because the acetate is usually liberated when the hemicellulose is hydrolyzed, as it is already acetylated.
To demonstrate the versatility of the strains in the present invention, both strains, JU15 and JU15A, had the gene that codes for the homologous lactate dehydrogenase of E. coli (IdhA) suppressed to disable D-lactate production. Next, the necessary coding gene or genes for the synthesis of other metabolites of industrial interest were inserted; L-lactate and ethanol were the metabolites of interest in the present invention. To illustrate, yet not limit, the versatility of the JU15 and JU15A strains, the first strain received the gene that codes for the lactate dehydrogenase of B. subtilis (see FIG. 40 ) and was subjected to a process of adaptive evolution in the presence of acetate; the new recombinant strain thus obtained was capable of not only growing with xylose as the main carbon source and in the presence of acetate but also producing L-lactate. This strain is labeled in the present invention as LL26 (deposited in the ARS Patent Culture Collection (NRRL) of the U.S. Department of Agriculture with access number NRRL B-50139) (Examples 12 and 13). In similar fashion to the JU15A strain, after suppressing the gene IdhA and inserting the Z. mobilis genes pdc and adhB, (see FIG. 41 ), another new recombinant strain was obtained that was capable of growing with xylose as its main carbon source in the presence of acetate and, in addition, of producing ethanol while efficiently consuming xylose; this project represents the first time that this combination of traits has been reported for strains of E. coli . This strain was labeled MS04 in the present invention and deposited in the ARS Patent Culture Collection (NRRL) of the U.S. Department of Agriculture with access number NRRL B-50138.
Thus, the present invention also refers to the methods of producing D-lactate, L-lactate or even ethanol from xylose as the main carbon source utilizing different fermentation processes and using the strains in the present invention.
In addition and with the purpose of showing the versatility of the strains in the present invention with regard to their use of several carbon sources, the growth possibility and acetate conversion of the strain JU15 was evaluated with lactose as the main carbon source, in mineral medium and with an agro-industrial residue, such as whey. The results show that this strain is capable of using lactose both for growth and for the conversion into a single metabolite of interest, in this case, D-lactate. Because this pathway is inherent to the parent strain used for the genetic modifications, it is obvious that the other strains, such as JU15A, MS04, CL3 and LL26, have the same ability.
Thus, the present invention yields new strains of genetically modified Escherichia coli for the versatile, efficient and preferential production of metabolites from the versatile consumption of a variety of low-cost carbon sources. Similarly, the present invention provides methods for the production of said metabolites from such carbon sources through their fermentation by those new strains.
For the construction of the strains of the present invention, the parent strain used was derived (see the Materials and Methods) from the strain E. coli MG1655, which was previously sequenced (Hayashi K., et al. 2006). To promote the efficient conversion of sugars (glucose, xylose, lactose, among others) into a preferential product of industrial interest (D or L-lactate, ethanol, etc.), the carbon flux toward other metabolites was eliminated through the suppression of genes that code for the fermentation metabolism enzymes and that compete for pyruvate (pflB and dhE, in the first step and frdA in a second step, see Examples 1, 2 and 3). This process yielded the strains CL1 and CL3, of which the latter is capable of growing and converting glucose into D-lactate at high rates, 0.22 h −1 and 4 g Lact /(g DCW *h) [DCW: dry cellular weight] (see Example 4 for details). Through the suppression of the genes that code for the ATP-dependent xylose transporter in the present invention, another improved E. coli strain was obtained and was labeled JU01 ( E. coli MG1655 ΔpflB ΔadhE Δfrd ΔxylFGH). Thus, for the first time, with the use of a symport-type transporter (xylose/H + ), an increased yield of ATP per mole of metabolized xylose was achieved, notably improving the capacity of the strains to grow in xylose as the only (or main) carbon source. This result was achieved through the suppression of the xylF, xylG and xylH genes (for details, see Example 5). However, this strain required a long period of time to consume the xylose present. Therefore, through a process of subsequent transferences in mineral medium with 12% xylose (adaptive evolution), the present invention yielded a mutant strain with an improved capacity for growing in xylose and for producing organic acids, such as D-lactate. This new strain is labeled in the present invention as JU15 (for details, see Example 6). This strain was characterized in mineral medium with xylose.
Afterwards, in a simulated hydrolyzed vegetable tissue medium that was abundant in xylose, although with relatively high acetate concentrations (because acetate usually is liberated when hydrolyzing hemicellulose, as it is acetylated, and such concentrations can dampen the growth of microorganisms in such media), it was observed that the JU15 strain showed an inconveniently prolonged lag phase of 12 h, which led the inventors to newly improve the strain. To this end, they subjected the JU15 strain to two steps of adaptive evolution in the presence of acetate, with the goal of obtaining a mutant with a significantly decreased lag phase. This new strain was labeled JU15A (see Example 7) and was subsequently characterized (see Examples 8 and 9).
Similarly, the possibility of using other carbon sources, such as certain industrial residues, including whey, which is rich in lactose (see Examples 10 and 11), was tested. Whey is considered to pose an environmental problem because it generates pollution when dumped in groundwater by considerably increasing the biochemical demand for oxygen, diminishing the availability of this important nutrient to the wild flora and fauna. To illustrate this possibility in the present invention, it was shown that the JU15 strain is capable of converting the lactose present in whey to D-lactate (see Example 11).
An additional objective of the present invention was to present a method for producing D or L-lactate that is optically pure from media rich in xylose, such as the hydrolysates of vegetable tissues, including sugar cane bagasse, using these new strains of E. coli . To this end, the inventors decided to genetically modify strain JU15 by the suppression of the gene that codes for E. coli lactate dehydrogenase and the insertion of the gene that codes for B. subtilis lactate dehydrogenase in the same JU15 strain. These modifications yielded a strain that produced L-lactate, labeled in the present invention as LL2 (Examples 12 and 13). To improve this strain's ability to grow in culture medium abundant in xylose, the inventors subjected strain LL2 to a procedure of adaptive evolution, obtaining an improved strain, labeled in the present invention as LL26 ( E. coli JU15,:: Idh Bs , for details, see Example 14).
Finally, with the goal of illustrating the application of MPE and adaptive evolution techniques for the production of other raw materials of great industrial and commercial interest, such as bioethanol, the inventors obtained a mutant strain of E. coli derived from JU15A. This strain was subjected to an interruption of Idha gene and the incorporation of the pdc and adhB genes of Z. mobilis , under the pflB promoter, in addition to the adaptive evolution process The mutant strain finally obtained was labeled in the present invention as strain MS04 ( E. coli JU15A ΔIdhA, PpflB:pdc Zm -adhB Zm ) and is capable of growing in culture media abundant in xylose as the most important carbon source and of producing ethanol with high productivity and yield (93% with respect to the theoretical maximum) (for details, see Example 15).
Thus, the present invention shows that modifications to the fermentation pathways and to xylose transport, followed by a selection process in subsequent transfers, yielded new genetically modified bacterial strains. These strains are capable of appropriately growing in mineral media abundant in xylose, glucose or lactose, among other sugars, and of converting the sugars present in vegetable hydrolysates, such as sugarcane bagasse, into only D or L-lactate or even into only ethanol. These strains can be used to obtain such products using formulated culture media based on vegetable hydrolysates, such as sugarcane bagasse.
Similar to the examples of L-lactate and ethanol, the strains in the present invention can have the IdhA gene suppressed and the necessary gene(s) inserted for the production of some other metabolite. For example, the pyruvate consumption pathways can be inactivated to thereby obtain a pyruvate-producing strain, or the strains can be forced to use homologous pathways for the production of succinate, 1,2-propanediol or malate as the only pathway of reducing power regeneration. Heterologous pathways, such as that of 1,3-propanediol, can be inserted to regenerate the reducing power, or L-alanine can be used as an amino acid that also allows the regeneration of the reducing power.
The selection of the starting strain from those described in this document will depend on several criteria, including the carbon source for fermentation and the possible presence of acetate in the culture media. Thus, for example, if the fermentation is to occur in glucose, strain CL3 can be used. In contrast, in xylose-rich media, JU15 can be used, and if the growth medium contains acetate, strain JU15A can be used. If the fermentation is to occur in lactose, any of the strains can be used. Despite not being the most optimal manner, strains LL26 or MS04 can be used, suppressing gene Idh Bs or genes pdc Zm and adhB Zm instead of gene IdhA and inserting the gene(s) that make it possible to produce the metabolite of interest.
MATERIALS AND METHODS
The microorganisms and plasmids used in the present invention are presented in Tables 1 and 2, and also in the SEQUENCE LISTING.
TABLE 1
E. coli strains used in this invention
Reference or
NRRL deposit
Strains
Genotype
number
Main phenotype
E. coli K12
E. coli MG1655
Wild type strain
Wild type strain,
heterofermentative
E. coli CL1
E. coli MG1655 ΔpflB
Utrilla et al., 2009,
Heterolactic, lactate
ΔadhE
NRRL B-50195
producer, succinate as
byproduct
E. coli CL3
E. coli MG1655 ΔpflB
Utrilla et al., 2009,
Homolactic (D-Lactate)
ΔadhE ΔfrdA
NRRL B-50195
E. coli JU01
E. coli MG1655 ΔpflB
This invention
Homolactic (D-Lactate),
ΔadhE ΔfrdA ΔxylFGH
Improved growth on
xylose
E. coli JU15
E. coli MG1655 ΔpflB
This invention, NRRL
Homolactic (D-Lactate),
ΔadhE ΔfrdA ΔxylFGH
B-50140
Improved growth on
E15
xylose
E. coli
E. coli JU15 derivative
This invention, NRRL
Homolactic (D-Lactate),
JU15A
with improved acetate
B-50137
Improved growth on
tolerance. JU15 Ac r
xylose. Acetate tolerant
E. coli LL26
E. coli JU15 ΔldhA
This invention, NRRL
Homolactic, L-Lactate
PldhA:: lctE Bs ,
B-50139
producer
E. coli
E. coli JU15A ΔldhA,
This invention, NRRL
Homofermentative,
MS04
PpflB::pdc Zm -adhB Zm
B-50138
Ethanol producer
Abbreviations:
Δ Deletion
P Promoter
pflB pyruvate formate lyase gene
adhE E. coli alcohol hydrogenase gene
frdA fumarate reductase gene
xylFGH ATP dependent xylose transport
E15 Evolved strain 15
JU15A JU15 derivative with improved acetate tolerance
ldh Bs B. subitilis L-lactate dehydrogenase de gene
ldhA E. coli lactate dehydrogenase gene
pdc Zm -adhB Zm Z. mobilis pyruvate decarboxylase and alcohol dehydrogenase genes
Ac r Acetate tolerant
TABLE 2
Plasmids used in this invention
Plasmid
Description
Reference
pKD46
Thermosensitive vector, arabinose
Datsenko and
inducible expression of the red
Wanner 2000
recombinase system
pKD4
Template used to amplify the Km
Datsenko and
resistance cassette flanked by FRT
Wanner 2000
sites
pCP20
Thermosensitive vector, used for the
Datsenko and
FLP recombinase expression
Wanner 2000
pKO3-plfB
pKO3 (Church et al 1999) derivative
Lara et al., 2006
with pflB homology regions
pTrclctE
pTrc99A derivative expressing the
Vázquez-Limón et
B. subtilis lactate dehydrogenase
al., 2007
pLDH Bs C
pTrclctE derivative with Cm
This invention
resistance gen cloned
(see FIG. 27)
pLOI510
Used as template for pdc and adhll
(Ohta et al., 1991)
PCR amplification
All plasmids and PCR products used in this work were analyzed by restriction patterns on agarose 1-1.2% gels electrophoresis.
Vegetal Tissues Hemicellulosic Hydrolysates such as Sugar Cane Bagasse
In the present invention sugar cane bagasse was used as an example, it was obtained from Emiliano Zapata's sugar mill in Zacatepec, Morelos, Mexico. The hydrolysis process for the production of fermentable sugars was carried out with sulfuric acid at different concentrations, temperature conditions, liquid-solid relation and time, as shown in the following section. Some hydrolysis tests were carried out in autoclave and most of them were carried out at pilot plant scale in a jacketed reactor.
The obtainment of sugar cane bagasse hemicellulosic hydrolysates was carried out in several stages: a) sugarcane bagasse homogenization b) dispersion of dilute sulfuric acid in the sugarcane bagasse at different liquid: solid ratios; c) selection of temperature, concentration and time for diluted acid hydrolysis treatment; d) obtaining of the hemicellulosic hydrolysates from bagasse; e) neutralization and detoxification of the hydrolysate by Ca (OH) 2 (30.5 g of Ca (OH) 2 /L hydrolyzed) addition based on the milliequivalents needed to raise pH ˜10-11 at room temperature, and f) concentration of the hydrolysate.
Hydrolysate Obtainment Conditions
Eight batches of hemicellulosic hydrolysates from sugarcane bagasse treated with sulfuric acid were conducted at pilot plant scale; treatments were divided into two groups: 1) Batches 1-4 and 2) Batches 5-8; furthermore, two batches were performed in a laboratory autoclave, The diluted-acid hydrolysis conditions for different groups in autoclave and pilot plant are indicated in Table 3.
TABLE 3
Group formation according to the acid: bagasse relation; hydrolysis
time; temperature and acid concentration.
Relation
Temperature
Acid concentration
Batch
H 2 SO 4 :Bagasse
Time (h)
(° C.)
(%)
PILOT PLANT - HYDROLYZATOR
GROUP 1
1
4:1
2
121
2
2
4:1
1
121
2
3
3:1
1
121
2
4
2:1
1
121
2
GROUP 2
5
2:1
2
140
4
6
2:1
1
121
4
7
2:1
2
121
2
8
2:1
1
140
2
AUTOCLAVE
1
2:1
1
121
4
2
2:1
1
121
2
In group 1, an evaluation of the liquid-solid ratio (H 2 SO 4 : bagasse) and time on the formation of fermentable sugars was carried out, keeping the temperature and acid concentration constant. From these results, the relation 2:1 was maintained constant (group 2) and a factorial experimental design was carried out. The dependent variables were: temperature (121 and 140° C.), acid concentration (2 and 4%) and time (1 and 2 hours). The final experimental design was 4 experiments (Table 4)
TABLE 4
Diluted acid hydrolysis conditions of sugar cane bagasse
H 2 SO 4
T
Time
(%)
(° C.)
(hours)
2
121
2
4
121
1
2
140
1
4
140
2
From the analysis of sugars in the hydrolysates, batches 4-8 were selected to be mixed, detoxified with Ca (OH) 2 at room temperature and concentrated in a Büchi Rotavapor 185 Ex, with the aim of increasing the concentration of sugars from ˜29 g/L to 70 g/L. As a last step, solid waste removal was carried in a centrifuge tube MiniSharples CL-I-1. In order to avoid pollution problems the detoxified hydrolysates were stored in a cold room (4° C.), and before starting a test they were sterilized by filtration (0.2 μm).
Strains and Cell Bank In the present invention the E. coli JU15 strain was handled in some cases. The JU15 strain is an E. coli MG1655 derivative, which was obtained from the strain collection of the inventors of this invention. JU15 strain has disrupted the ethanol, formate-acetate and the succinate production pathways, and the ATP dependent xylose transport system. The inventors of the present invention assume that the route used to transport xylose is a symport. JU15 genotype is E. coli ΔadhE ΔpflB ΔxylFGH. In the cases where acetate was present in the culture medium, a JU15 derivative was used, the JU15A strain; this strain was adapted to grow faster and more efficiently in the presence of acetate. The JU15A strain was obtained from two serial cultures of JU15 strain in AM2 medium containing xylose and acetate as carbon sources.
Cell banks were generated, for both strains: JU15A JU15, from exponentially growing cells; one mL of each strain culture (JU15A and JU15) was frozen mixed with one mL of 80% glycerol into 2 mL cryovials, after mixing the culture with glycerol dry ice was used for a very fast freezing. With the purpose of having an inoculum with the same conditions throughout the study cryovials, with frozen cells, were stored at −70° C. in a ultra freezer.
Conditions and Culture Media
Inoculum: Escherichia coli JU15 y JU15A
In a mini-fermenter (fleaker) with 200 mL of mineral medium (AM2, Martinez et al., 2007) and 20 g/L of xylose or glucose, the latter only in cultures where glucose was used as the sole carbon source, cells were added from a glycerol cryovial. Temperature was controlled to 37° C. with a thermal bath and stirring was controlled to 100 rpm. The inoculum was incubated for 24 h until reaching an OD600 approx. 1.5-2. The cultures were inoculated by centrifugation (4000 rpm, 10 minutes at room temperature), to provide enough cells for an initial OD600 of approximately 0.1 (0037 gDCW/L) in the culture. Subsequently, cell pellets were transferred to each culture by suspending them in the culture media. The inoculum for JU15A strain was carried out under the same conditions as for JU15 strain, with the only difference that the culture medium contained 20 g/L xylose and 1.48 g/L acetate in 200 mL of mineral medium (AM2).
Culture Media and Control Cultures
The AM2 medium composition for fleakers cultures (Martinez et. al., 2007) was: 2.63 g/L (NH 4 ) 2 HPO 4 , 0.87 g/L NH 4 H 2 PO 4 , 1.0 mL/L MgSO 4 7H 2 O (1M), 1.5 mL/L trace elements, 1.0 mL/L KCl (2M), 1.0 mL/L Betaine HCl (1M), 100 mg/L citric acid. The medium was supplemented with different concentrations of xylose, glucose, arabinose and/or sodium acetate. The trace element solution contains per liter: 1.6 g FeCl 3 , 0.2 g CoCl 2 .6H 2 O, 0.1 g CuCl 2 , 0.2 g ZnCl 2 4H 2 O, 0.2 g Na 2 MoO 4 , 0.05 g H 3 BO 3 y 0.33 g MnCl 2 .4H 2 O.
Hydrolyzed Supplemented Cultures Labeled from A-F
In cultures AF, elements of the AM2 medium were used in different proportions but at the same concentration mentioned above. The Table 5 summarizes the proportions of each of these elements, using the following abbreviations Salts: (NH 4 ) 2 HPO 4 and NH 4 H 2 PO 4 , Mg, MgSO 4 .7H 2 O; Bet: betaine HCl; T.E. trace elements, C.A.: citric acid and KCl: KCl. The A to F cultures media were supplemented with 50 g/L xylose, 6.7 g/L glucose, 3.3 g/L arabinose and 1.48 g/L sodium acetate.
TABLE 5 AM2 medium composition used in A-F cultures (A) (B) (C) (D) (E) (F) 1X Bet 1X Bet 1X Bet 1X Bet 1X Bet 1X Bet 1X C.A. 1X C.A. 1X C.A. 1X C.A. — — 0.25X Salts 0.25X Salts 0.25X Salts 0.25X 0.125X — Salts Salts 0.25X KCl 0.25X KCl 0.25X KCl — — — 0.25X Mg 0.25X Mg — — — — 0.25X T.E. — 0.25X T.E. — — —
Culture Conditions
Fleakers (250 mL Mini-Fermentors)
Anaerobic cultures were carried out in fleakers (mini-fermentors) (Beall et al., 1991) with a 200 mL working volume. Temperature was controlled to 37° C. with a thermal bath and stirring was controlled to 100 rpm. The pH was controlled in the range of 6.6 to 7.0 with the automating addition of KOH 2N or 4N. The stirring was maintained at 100 rpm using a magnetic cross stirrer with a diameter of 2.54 cm. All experiments were carried out at least by duplicate and in most of the cases by triplicate.
The fleaker system used in the present work has the following elements: a) 6 mini-fermentors (300 mL) with a magnetic stirrer; b) a temperature control consisting in a thermocycler and a water bath; c) a pH controller, consisting of six automated controllers with valves used to release the base, and six pH electrodes: d) stirring control integrated by a magnetic plate (100-850 rpm).
10 L Fermenter
The anaerobic cultures in a greater volume where carried out in a pilot scale 10 L fermentor (Microferm, New Brunswick, N.J., USA). The controlled conditions of pH, temperature and stirring speed were kept in the values 6.6-7.0, 37° C. and 240 rpm respectively. The pH was controlled with the addition of 4N KOH base and the temperature was controlled with an internal coil. A marine propeller impeller was used to keep the agitation.
Analytic Methods
Spectrophotometric Determination of the Cell Concentration
The optical density was measured at 600 nm (OD 600 ) in a spectrophotometer Beckman (DU-70) (Beckman instrument, Inc. Fullerton, Calif., USA) and it was converted to dry cellular weight (DCW) according to a calibration curve: 1 OD 600 equal to 0.37 g DCW /L. All the samples were centrifuged (5,000 rpm at room temperature) the cell pellet was discarded and the supernatant was frozen for latter analyzes.
Viable Count (CFU)
The number of cells in the cultures with hydrolysates, where the medium did not allow measuring the optical density was measured by viable count of colony forming units (CFU) and converted to a number of cells per milliliter (cells/mL) by considering the dilution respectively. Similarly, all samples were centrifuged (5,000 rpm at room temperature) separating the supernatant for further analysis.
Determination of Organic Acids and Sugars
Calculation from the Base KOH Consumption (Organic Acids)
The base consumption used for pH control during a growth kinetic gives an approximate value of the organic acid (lactic acid) present in the medium. The calculation for the determination of the organic acid concentration (C A ) is made using the following known data: base concentration (C B ); consumed base volume (V BA ); initial working volume in the mini-fermentor (V T ). and the equation 1:
C A = ( C C ) ( V BA ) V T Equation 1
where:
C A and C B , are molar concentrations (mol/L) V BA and V T , are in mL
Quantification of Organic Acids and Sugars by High Performance Liquid Chromatography (HPLC)
The determination of organic acids and sugars by HPLC was carried out by isocratic chromatography with a solution of 5 mM H 2 SO 4 as mobile phase at a flow rate of 0.5 mL/min in an Aminex HPX-87H column (Biorad) at 50° C. The detection of the separated compounds was carried out simultaneously with a diode array detector (Waters 996) and a refractive index detector (Waters 410). The data processing and analysis was performed with the “Millennium” software (Version 3.01 Waters). The internal and external temperatures of the column were adjusted to 45 and 50° C. respectively. The supernatants of the samples to be analyzed were filtered with 0.45 μm membrane and automatically injected using the autoinjector (Waters 717). For confirmation of the sugars and the products analyzed HPLC standards of xylose, glucose, arabinose, sodium acetate and organic acids were injected. The data obtained from the concentrations of each of the analyzed compounds were calculated with a calibration method-Interpolation of the same software.
Kinetic Parameter Evaluation of the Fermentation Processes.
The evaluated parameters were: specific growth rate (μ); cell mass/substrate yield (Y X/S ); product/substrate yield (Y P/S ); product/cell mass yield (Y P/X ); volumetric productivity of the desired product (P); specific substrate consumption rate (q S ); specific production rate (q P ). All of them where calculated during the exponential growth phase of each bacterial strain generated in the present invention. In order to calculate the kinetic parameters, the dilution factor caused for the addition of the base for pH control was considered. The dilution factor (F D ) is given by the amount of added base to the initial working volume (Equation 2). The way to correct the substrate, product and cell mass measurements is multiplying by the dilution factor.
F D = ( V I + V BA ) V I Equation 2
where:
V I , is the initial working volume in mL V BA , is the volume of added base used for pH control in mL
EXAMPLES
In the following examples, the invention is better illustrated, although its possible uses extend beyond these examples.
Inactivation of Fermentative Genes in the Bacterial Strains
The microorganisms, plasmids and primers used in the present invention are shown in the MATERIALS AND METHODS section or in the SEQUENCE LIST appendix.
Example 1
pflB Gene Suppression
As the first part of the present invention, the gene pflB of the E. coli strain MG1655 was suppressed using the plasmid PKO3-pflB (Lara et al., 2006). The pflB suppression was verified with PCR ( FIG. 4 ) using the parent strain as a control and another mutant strain of E. coli , ΔpflB W3110.
The expected PCR product in the mutants corresponds to 1.7 Kbp, or to 4.5 Kbp in false positives, which is the size corresponding to the amplification of the intact gene. From the analysis of different gels, 7 mutants were selected. From these strains, cultures were grown in test tubes in AM2 media with 10 g/L of glucose and at 37° C. to verify the fermentation products after 24 h ( FIGS. 5 and 6 ).
The phenotype observed in the colonies that have pflB suppression was a noticeable decrease in the products that are obtained from a reaction catalyzed by pyruvate formate lyase, that is, formic and acetic acids and ethanol, with a concurrent substantial increase in the production of lactic acid. As is seen in FIGS. 5 and 6 , with the exception of colony number 26 (false positive), this phenotype is found in all of the colonies analyzed.
Example 2
adhE Gene Suppression
To perform the adhE gene suppression, a PCR product with regions homologous to this gene was obtained with the Adh Forw primers (SEQ. ID NO: 1) and Adh Rev primers (SEQ. ID NO: 2), and the plasmid pKD4 was used as a template (Datsenko and Wanner 2000). The product was electroporated into cells induced with arabinose and with a co-plasmid (pKD46). Several colonies resistant to kanamycin were obtained and analyzed with PCR with the adhck forward and reverse primers (SEQ. ID NO: 3 and SEQ. ID NO: 4, respectively), which amplify a 3.0-Kbp product corresponding to the regions 200 by downstream and upstream plus the adhE (2.6-Kbp) gene. Following suppression, a 1.9-Kbp product, corresponding to the kanamycin-resistance cassette and the adjacent regions already mentioned, is obtained.
FIG. 7 shows the 1.9-Kbp fragment obtained by adhE gene suppression, which yielded the E. coli strain MG1655 ΔpflB ΔadhE that was labeled as CL1 in the present invention.
Example 3
frd Gene Suppression
To carry out the frd gene suppression, a PCR product with regions homologous to target gene was obtained using the frd Forw and frd Rev primers (SEQ. ID NO: 5 and SEQ. ID NO: 6, respectively) and the plasmid pKD4 as a template (Datzenko and Wanner 2001). This product was electroporated into cells induced with arabinose and with the co-plasmid (pKD46). Several colonies resistant to kanamycin were obtained and analyzed with PCR with the frdck forward and reverse primers (SEQ. ID NO: 7 and SEQ. ID NO: 8, respectively), which amplify a 1.9-Kbp product that corresponds to regions 50 bp downstream and upstream, plus the frd gene (1.8-Kbp). Following suppression, a 1.6-Kbp product is obtained, corresponding to the kanamycin-resistance cassette and the adjacent regions already mentioned.
The E. coli strain obtained, which was resistant to kanamycin, was transformed with the pCP20 plasmid carrying the FLP recombinase gene. The latter was grown in petri dishes with ampicillin, yielding isolated colonies. The colonies were selected for the loss of kanamycin resistance. The colonies obtained that were sensitive to kanamycin were evaluated by PCR to verify the suppression. The PCR yielded a product near 200 bp, which corresponds to the sites adjacent to the gene and to the FRT sequences that recognize FLP recombinase. This process yielded the strain labeled as CL3 ( E. coli MG1655 ΔpflB adhE Δfrd) in the present invention.
Example 4
Phenotype Characterization of CL3
To characterize the CL3 strain ( E. coli MG1655 ΔpflB ΔadhE Δfrd) obtained by Utrilla et al., 2009, cultures were cultivated in mini-fermentors with controlled pH in AM2 medium, which has a low salt content and is optimized for the anaerobic growth of E. coli (Martinez et al., 2007), and with 40 g/L of xylose or glucose. The specific growth rate and the production level of lactate, ethanol, acetate, formate and succinate were obtained. Strain CL1, from which strain CL3 is derived, was characterized in mineral medium with xylose or glucose at a concentration of 40 g/L. The CL3 strain in AM2 medium with xylose and glucose has a growth rate similar to that obtained for CL1 in mineral medium with xylose or glucose, but there is an increase in cell mass production of 38% and 14% in xylose and glucose, respectively. In contrast to the other mutant pfl strains that have been reported (Zhou et al. 2003a), the CL1 and CL3 strains have the capacity of growing at 0.22 h −1 . This increase in cell mass production had an effect on the consumption of sugar and on the lactate productivity. In glucose, 40 g/L of sugar was consumed in approximately 24 h, and a lactate yield close to the theoretical value (1 g of lactate/g of glucose) was obtained, equivalent to a volumetric productivity of 1.66 g of lactate/h ( FIG. 8 ). In xylose, the 40 g/L of sugar was consumed in approximately 72 h by the CL3 strain in AM2 medium, in contrast to the findings with the CL1 strain in mineral medium. In this case, after 96 h, approximately 10 g of xylose remained ( FIG. 8 ). For both sugars, it was found that frd gene suppression eliminated succinate production, resulting in D-lactate ( FIG. 9 ) and acetate as the only products of the CL3 strain. Acetate was found in concentrations below 2 g/L in the medium with glucose and below 5 g/L in the medium with xylose at the end of the fermentation (data not shown).
Example 5
Suppression of the ATP-Dependent Xylose Transport System
The inventors of the present work suppressed the ATP-dependent xylose transport system (xylF, xylG and xylH genes) using the technique of inactivation of chromosomal genes by a PCR product (Datsenko and Wanner, 2000). The inventors obtained a PCR product of 1.6 Kbp using the Xyl Forw and Xyl Rev primers (SEQ. ID NO: 9 and SEQ. ID NO: 10, respectively) and the plasmid pKD4 as a template. This product corresponded to the kanamycin cassette with regions homologous to the genes to be suppressed. The xylck Forw and xylck Rev primers (SEQ. ID NO: 11 and SEQ. ID NO: 12, respectively) were designed to amplify the regions adjacent to the xyIFGH genes, which have a size of 3.7 Kbp in the wild strain and 1.6 in the suppressed strain ( FIG. 10 ).
The inventors obtained the strain labeled in the present invention as JU01 ( E. coli MG1655 ΔpflB ΔadhE Δfrd ΔxylFGH), which was tested in AM2 medium with 40 g/L of xylose. It was found that JU01 grows 37% faster than the CL3 strain (p=0.14 h −1 ) ( FIG. 11 ) and completed the fermentation of 40 g/L of xylose in 72 h. This result suggests that a higher yield of ATP per mole of metabolized xylose can be obtained when using alternative transport systems that do not depend on ATP (most likely XylE). However, compared with the results obtained with glucose, JU01 takes three times the amount of time to consume 40 g/L of xylose, and the volumetric productivity of organic acids is affected, producing a third of what is obtained in glucose. This result indicates that improving the xylose consumption rate can potentially help obtain lactate production velocities similar to those obtained with glucose.
Example 6
Adaptive Evolution of the JU01 Strain and Optimization of the Production pH for the Derived Strain
Based on the statements in the previous paragraph, the developers of this invention subjected the JU01 strain to a process of adaptive evolution in AM2 medium with 40 g/L of xylose (as the only carbon source); nine transfers were performed, and none of these was able to significantly increase the growth rate or the organic acid production as determined through the consumption of the base used to control the pH. A concentration of 120 g/L of xylose was used to increase the selection pressure and to obtain mutants with a better capacity to grow in xylose. Six transfers were conducted, and in the present invention, the growth capabilities and organic acid production of the JU01 strain were improved ( FIG. 12 ), yielding a new strain of E. coli labeled in the present invention as JU15.
There are reports in which fermentations are performed at different pH values for lactic acid production, using strains derived from E. coli B and E. coli K12 (Dien et al., 2001). However, in the case of E. coli JU15, because it is a new strain, its behavior was unknown when fermenting at different pH values. For this reason, the inventors characterized the fermenting process at the pH values 5.8, 6.2, 6.6, 7.0, 7.4 and 7.8 in mineral medium enriched with 6% xylose and in fermentation processes lasting 72 h to obtain the optimal pH conditions for the best growth of the strain. FIG. 13 shows the behavior obtained when the pH is varied, and Table 6 summarizes the experimental kinetic parameters.
As seen in Table 6, one of the optimal pH values for the process developed in the present invention is 7.0, but lactate can be produced without a problem from a value of 5.8 up to 7.8.
TABLE 6
Kinetic parameters of E. coli JU15 strain at different pH values
*X
X max
*μ
*q P
P
pH
(g/L)
(g/L)
(h −1 )
(g lactate /g cell mass · h)
(g lactate /L · h)
7.8
0.08
1.25
0.068
2.06
0.66
7.4
0.22
0.96
0.147
2.57
0.68
7.0
0.07
1.61
0.150
8.97
0.73
6.6
0.32
1.36
0.175
3.07
0.71
6.2
0.28
0.77
0.171
2.85
0.50
5.8
0.21
0.42
0.142
2.20
0.23
*Values obtained during exponential growth phase
Example 7
Characterization of E. coli JU15 and JU15A in Mineral Medium Simulating Hydrolysate Composition
For the present invention, the new strain JU15 has also been characterized in a simulated vegetable tissue hydrolysate, numbering it as 1 (simulated hydrolysate 1). For this experiment, the mineral medium AM2 was used with the addition of other major components in the following concentrations: xylose 50 g/L, glucose 6.7 g/L, arabinose 3.3 g/L and acetic acid 1.1 g/L. The total sugar concentration was 60 g/L, and the pH value started at 6.6 and changed to pH 7.0 at the start of fermentation. In this culture medium, it is seen that the strain had a dampened growth phase of 12 h because of the presence of acetic acid, causing a possible growth inhibition effect for the JU15 strain ( FIG. 14 ). This strain finally reached a specific growth rate (μ) of 0.12 h −1 and a q P of 1.93 g lactate /g cell mass ·h after 96 h. Due to the dampened growth phase, the inventors carried out two passes in the presence of acetate to improve the growth of the strain, by which process another new strain was obtained, named JU15A in the present invention. To illustrate its behavior, another control culture was performed with this evolved strain, adding sodium acetate to the inoculum. The behavior obtained is shown in FIG. 15 , demonstrating that the inventors eliminated the lag phase that the strain JU15 normally exhibits, thereby demonstrating better tolerance to acetic acid than the other strains previously reported (Lawford and Rousseau, 1992). Because this result contrasts with the behavior shown by E. coli K12, which was inhibited by the addition of 35 mM of sodium acetate (Lawford and Rousseau, 1992), this observation shows that, despite the microorganism being the same ( E. coli ), the difference between strains indicates tolerance to inhibition by acetic acid.
For the new strain JU15A, neither the q P nor the productivity (P) was affected by the addition of 1.1 g/L of acetic acid to the simulated hydrolysate 1 (AM2 medium with added xylose, glucose and arabinose) (see Table 7). FIG. 16 shows the kinetics of E. coli JU15A in the simulated hydrolysate 1, which was conducted by the inventors of the present invention at 100 rpm, with the pH maintained in the interval 6.6-7.0 and at a temperature of 37° C. Under these conditions and with the evolved strain, the specific growth rate increased 1.5 times. The volumetric productivity (P, g lactate /L/h) was obtained by dividing the final concentration of lactic acid by the total time of the fermentation. The final product yield was determined according to the maximum obtained lactate concentration divided by the total sugar concentration consumed in the media, yielding in this case 100% of the theoretical value. Table 7 summarizes the kinetic parameters obtained in the present invention.
TABLE 7
Kinetic parameters of the evaluation of E. coli JU15A
in hydrolyzed simulated medium 1.
*μ
X max
X max
(h −1 )
*q S
*q P
*Y X/S
Y P/S
P
(g/L)
(CFU/mL)
0.18
1.80
3.27
0.097
1.06
0.70
1.64
4.8 × 10 10
Y P/S : g lactate /g sugar ;
Y X/S : g cell mass /g sugar ;
q P : g lactate /g cell mass · h;
q S : g sugar /g cell mass · h; and
P: g lactate /L · h.
*Values obtained during exponential growth phase
Looking at FIGS. 16 and 17 , the simultaneous consumption of two carbon sources can be observed in the first instance: glucose-arabinose and afterward, with glucose exhausted, the simultaneous consumption of xylose-arabinose. The formation of cell mass shows that the phenomenon of catabolic repression by the preference for one carbon source does not occur, and the behavior does not show diauxic (two-stage) growth. Similarly, FIG. 16 shows that acetate was not consumed, which is why this compound is not considered to be a carbon source for the new E. coli JU15A strain. In the fermentation process of the present invention, there is only a total production of 2.3 g/L of acetic acid, considering the initial and final concentration at the end of the fermentation.
Additionally, the inventors of the present invention determined that in fermentations with the new strain JU15A, the carbon sources (xylose, glucose and arabinose) were totally consumed and that the lactate production achieved 100% of the theoretical yield. There was no acetate consumption, but this compound was produced after 24 h. There was no formation of ethanol or formate, and trace concentrations of fumarate were detected.
When comparing the new strains JU15 and JU15A, the effect of acetate is seen as causing a larger dampened growth phase, which results in a decrease of the specific growth rate and productivity. Acetic acid is typically used as an antimicrobial agent in the food industry because it is known for its inhibitory effect on bacteria and yeasts. This compound inhibits growth because of its ability to travel freely across the membrane, acidifying the cytoplasm, collapsing the transmembrane pH gradient and destabilizing homeostasis with respect to the intracellular pH.
Afterward, the inventors of the present invention tested the new E. coli strain JU15A in a second control culture (simulated hydrolase 2) under the same pH, temperature and rpm conditions but changing the concentrations of the components present in the AM2 medium. In other words, the amount of (NH 4 ) 2 HPO 4 and NH 4 H 2 PO 4 salts were reduced by one quarter without adding KCl, MgSO 4 7H 2 O or trace elements and maintaining the concentration of betaine and citric acid at a constant level, as well as those of the carbon sources (xylose, glucose and arabinose) and acetate. Table 8 and FIGS. 18 and 19 summarize the results obtained in this fermentation process.
TABLE 8
Kinetic parameters of the evaluation of E. coli JU15A
in hydrolyzed simulated medium 2.
*μ
X max
X max
(h −1 )
*q S
*q P
*Y X/S
Y P/S
P
(g/L)
(CFU/mL)
0.16
3.09
1.63
0.05
0.19
0.14
0.14
1.3 × 10 10
Y P/S : g lactate /g sugar ;
Y X/S : g cell mass /g sugar ;
q P : g lactate /g cell mass · h;
q S : g sugar /g cell mass · h; and
P: g lactate /L · h.
*Values obtained during exponential growth phase
When comparing the control cultures with simulated hydrolysates 1 and 2, the inventors of the present invention clearly observed that the absence of potassium salts, magnesium and trace elements and lesser amounts of phosphate salts (nitrogen source) directly affected the growth of the new JU15A strain, even with specific growth rates (μ) being similar between the two cultures. The other kinetic parameters are drastically reduced, and the maximum cell mass reached in simulated hydrolysate 2 was 11 times less than that in simulated hydrolysate 1. Unexpectedly, and despite the amount of cell mass being lower in control culture 2, q S has a greater value (1.7 times in the exponential phase) for control culture 2. This result demonstrates, along with the value of μ, that at first, there is good growth that is rapid, but afterwards, the lack of essential nutrients results in an inability to maintain growth, which is why JU15A is limited in this type of culture.
Example 18
Characterization of E. coli JU15A in Cultures with Hydrolysates (A-F) in a System of Mini-Fermenters (Fleakers)
The inventors of the present invention also conducted experiments to test the effect of supplementing the culture medium with nutrients, both on productivity and on lactate yield. The inorganic salts of the AM2 medium were selected, and the concentrations were varied to supplement the hemicellulose hydrolysates of the vegetable tissues that were utilized, such as sugar cane bagasse, and to select the most appropriate culture medium to subsequently scale up the fermentation process to a 10-L operating volume. The results obtained when the hydrolysates contain both sugars (xylose, glucose and arabinose) and acetic acid are summarized in Table 5. The main results obtained from the fermentations with vegetable tissue hydrolysates, such as sugar cane bagasse, are shown in Table 9, and FIGS. 20 , 21 and 22 show the behavior of JU15A in A-F cultures. Although the specific growth rate, volumetric productivity and product-substrate yield remained similar for cultures A-E, the cell mass achieved in the hydrolysates without supplements of magnesium, potassium and trace elements was 7.5 times less, which demonstrates a limitation caused by the fermentation medium that may affect various parameters, such as the cell mass-substrate yield and the specific rates of substrate consumption and product formation, which depend directly on the formation of cell mass.
TABLE 9
Kinetic parameters of the fermentation of different hemicellulosic
hydrolysates from sugar cane bagasse.
JU15A
Kinetic parameter
A
B
C
D
E
F
X max (CFU/mL)
5.9 × 10 10
5.5 × 10 10
4.9 ×
7.9 ×
7.7 ×
6.1 ×
10 10
10 9
10 9
10 9
*μ (h −1 )
0.19
0.21
0.20
0.23
0.23
0.22
Y P/S (g lactate /g substrate )
1.14
1.14
1.11
1.09
0.98
0.66
P (g lactate /L · h)
0.77
0.77
0.75
0.77
0.70
0.45
*Values obtained during exponential growth phase. The nutrient addition is as detailed in table 5.
For the sugars, the glucose was totally consumed in all of the fermentations within 24 h. The arabinose was completely consumed for fermentations A-D in a period no greater than 48 h, but for fermentations E and F, in which the salt supplementation was very little or none, the arabinose was consumed in 72 h for the first case, and total consumption was not achieved in the second case. Similarly, the xylose was completely consumed in 72 h for four cases (A-D), with xylose remaining in the last two fermentations (E and F). However, in contrast to the results observed in the simulated hydrolysates, acetate was consumed in certain cases, indicating its participation as a carbon source under certain conditions and indicating that it does not act as an inhibiting compound for the growth of E. coli JU15A.
When the inventors of the present invention compared culture A with simulated hydrolysate 1, they observed similar results to those reported in the preceding tables for the documentation of the present invention with respect to the kinetic parameters, with a slight decrease in the amount of cell mass formed (4.8×10 10 & 5.9×10 10 UFC/mL). However, when comparing culture D, which has a similar medium composition with simulated hydrolysate 2, a μ value that was 1.4 times larger was obtained, along with a product-substrate yield that was ˜6 times larger and a volumetric productivity that was 5 times larger. These results indicate that the components found in the hydrolysates benefit the metabolism of JU15A.
Unexpectedly, the specific growth rates obtained for cultures A-F were greater than those previously reported. In the present invention, when JU15A strain was tested in mineral media at different conditions for glucose/xylose and despite the total sugars in the fermentations not being completely consumed, the yield surprisingly surpassed the theoretical maximum reported in the majority of cases. This observation leads to the conclusion that hydrolysates have other carbon sources that are converted to D-lactate and that were not considered in the control cultures. In addition, the present characterization surprisingly showed that the addition of supplemental compounds, such as KCl, MgSO 4 7H 2 O or trace elements, is not necessary, as the new strain, JU15A, has the capability of growing with only the addition of a nitrogen source—(NH 4 ) 2 HPO 4 and NH 4 H 2 PO 4 salts) and of producing a large amount of D-lactate rapidly, showing that the hemicellulose hydrolysates of vegetable tissue, such as sugar cane bagasse, provide an adequate fermentation medium. To illustrate the invention utilized in a 10-L fermentation, the medium composition of culture D was selected because it gave good yields and productivity, despite not forming the maximum amount of cell mass obtained in other fermentations reported for the present invention.
Example 9
Characterization of E. coli JU15A in Culture Medium D in a 10-L Fermenter
The inventors conducted the characterization of the new strain of E. coli , JU15A, in the hemicellulose hydrolysates of vegetable tissue, such as sugar cane bagasse, with added betaine, citric acid and phosphate salts in a 10-L pilot fermenter. The operating parameters, such as the temperature and pH, were the same as those used in the mini-fermenters, and the shaking rate was empirically determined to achieve homogeneous mixing of the hydrolysate in the bioreactor (240 rpm). The data obtained during the fermentation process are shown in Table 10 and FIG. 23 . These results showed that there was rapid growth, reflected in a μ value of 0.28 h −1 . However, there was a yield greater than the theoretical maximum, Y P/S de 1.3 g lactate /g sugar , because of other compounds, aside from sugars, that are present in the hydrolysates and that serve as a source of carbon. Although the xylose was not completely consumed, the final volumetric productivity attained was 0.50 g lactate /L·h, which is lower in comparison to fermentations carried out in mini-fermenters (Fleakers) under similar conditions.
TABLE 10
Kinetic parameters of E. coli JU15A strain in a 10 L fermentation.
*μ
Y P/S
P g lactate /
X max
(h −1 )
g lactate /g sugar
L · h
(CFU/mL)
0.28
1.30
0.50
6.0 × 10 9
*Exponential growth phase
The hydrolysate that was used in this experiment was stored for several months at 4° C., and it had a concentration of 15.9 g/L of acetic acid at the start of the 10-L culture. FIG. 23 shows that the acetate was not consumed and actually had a slight increase in its concentration (+6 g/L), once again showing the remarkable ability of the new strain of E. coli , JU15A, to maintain its growth in concentrations of up to 15.9 g/L of acetic acid (265 mM) or of up to 36 g/L of sodium acetate. The amount of cell mass formed did not reach the maximum values attained by the cultures cultivated in the mini-fermenters. This result could be due to the high concentration of acetate in the medium, which, although not completely inhibiting, can have a slight impact on the growth of the strain.
Example 10
Lactose Fermentation
For the present invention, the capacity of the JU15 strain to use lactose as a carbon source in AM2 mineral medium with 4% lactose to produce lactate was tested, and the following results were obtained: a) strain JU15 consumes lactose at the same rate as its parent JU01 (see FIG. 24 ) and b) this strain is capable of converting lactose into D-lactate with yields higher than 95% and productivities of approximately 1 g/L·h. The data obtained from the fermentation process in the present work are shown in FIGS. 24 and 25 .
Example 11
Fermentation of Whey
For the present invention, it was considered to be important to evaluate the capability of the JU15 strain to ferment other low-cost raw material sources, such as whey (Nutting, 1970). Taking into account the chemical composition of whey, only betaine was added (at a 1 mM concentration) as an osmoprotector for the whey. In addition, the present invention tested the fermentation of whey supplemented either with 50 g/L of lactose or of xylose. It was not possible in these fermentations to quantify the growth of the strain via optical density, due to the initial turbidity of the whey. Therefore, the fermentation of whey was determined by the consumption of the base used to neutralize the lactic acid produced.
The results obtained in this part of the present invention showed two relevant findings: a) strain JU15 can grow in and ferment the sugars present in whey and b) the productivity of the process was lower than that obtained using AM2 mineral medium, which was most likely due to whey being limited in minerals required for the growth of JU15 ( FIG. 26 ).
Example 12
Integration of L-Lactate Dehydrogenase from Bacillus subtilis for the Production of L-Lactate
Construction of the pLDH Bs C Plasmid
During the development of the present invention, this plasmid was constructed with the goal of using it as a template for the PCR to be used in chromosome integration. Starting from the pTrclctE plasmid (Vázquez-Limón et al., 2007), the inventors constructed the plasmid pLDH Bs C by cloning the PCR fragment containing the gene that confers resistance to chloramphenicol (Cm r ) flanked by FRT sites that facilitated the recombination in the chromosome. This fragment was obtained from the pKD3 plasmid (Datsenko and Wanner 2000). The Cm r gene in the pLDH Bs C plasmid was downstream of the lactate dehydrogenase gene of B. subtilis (Idh Bs ) (see FIG. 27 ).
Example 13
Insertion of the B. subtilis Idh Gene in the Chromosome of JU15
The inventors of the present invention had to design a pair of primers with homologous regions at the start and finish of the Idh gene of E. coli in order to insert the Idh Bs gene in the JU15 strain. The insertion of the Idh Bs gene into the chromosome of JU15 was accomplished through the modification of the strategy provided by Datsenko and Wanner 2000. Initially, the inventors designed a pair of primers to amplify a DNA fragment that contains the Idh Bs gene and the chloramphenicol resistance cassette flanked by FRT sites using the pLDH Bs C plasmid.
The specific primers EcLDHBsIntFw (SEQ. ID NO: 13) and EcLDHBsIntRv (SEQ. ID NO: 14) have homology with the regions adjacent to the gene that is to be suppressed (H1 and H2) and with the plasmid (pKD3) template (P1 and P2) that contains the gene for resistance to chloramphenicol flanked by FRT sites.
FIG. 28 depicts a gel used in the analysis of the colonies as previously described. Lane 1 shows the molecular weight marker, and lanes 5 and 6 correspond to strain LL1 (JU15 ΔIdhA::Idh Bs Cm). A PCR product was amplified that coincided with the expected molecular weight (2,663 bp) when the heterologous gene was inserted.
The inventors obtained strains resistant to Cm and, using PCR, confirmed a fragment that corresponded to the size of the Idh Bs gene and the Cm resistance cassette, which is why the inventors assumed a successful insertion of the heterologous Idh Bs gene and the Cm resistance cassette. The PCR indicated that the Idh Bs gene is under the control of the native promoter of E. coli.
The inventors transformed the LL1 strain with the pCP20 plasmid, which contains FLP recombinase, which, in turn, recognizes FRT sites. The FRT sites flank the gene responsible for conferring resistance to chloramphenicol. The inventors carried out a simple recombination in which the cat gene was excised, leaving only a single FRT site in the chromosome.
In the present invention, Primer 1189 Fwd (SEQ. ID NO: 15) and Primer 1190 Rvs (SEQ. ID NO: 16) were designed to verify this suppression, and these primers showed regions of homology 200 by before and after E. coli IdhA.
The inventors obtained a product close to 1,093 bp, which corresponded to the sites adjacent to the gene and the FRT recognition sequences of FLP recombinase. Thus, they obtained the strain labeled in the present invention as LL2 ( E. coli MG1655, ΔpflB, ΔadhE, ΔfrdA, ΔxylFGH, IdhBs, km r ) (LL2 lakes Cm r ) (see FIG. 40 ). The PCR products of the colonies with a suppressed IdhA gene and that lack the gene that confers resistance to Cm are shown in FIG. 29 , lanes 2 to 6; the control JU15 strain is in lanes 7 and 9 with a 1,069-bp product, and lane 8 corresponds to a negative control of 1-860 bp.
From strain LL2, the inventors obtained five colonies that were then phenotypically characterized. These colonies were denominated as LL2, with the addition of a parenthesized range number (1-5). The following parameters were tested: growth, glucose consumption and consumption of the 2 N KOH base, using minimal AM2 media in anaerobic conditions at a temperature of 37° C. and stirring at 150 rpm.
The inventors observed that the strains labeled as LL2(2) and LL2(3) showed lag phases of 12 and 24 h, respectively, (data not shown) which is why they decided to subject these two strains to the process of adaptive evolution.
Example 14
The Adaptive Evolution of the LL2 Strain in 40 g/L Xylose
The adaptive evolution consisted of performing culture transferences when the culture was in the exponential phase from one mini-fermenter to another along with 40 g/L of the carbon source (xylose), which was inoculated to an optical density of 0.01 (0.0037 g DCW /L).
The inventors required six passes to obtain a constant behavior, that is, a state from which the capacity to grow in xylose did not improve. The strain that was finally obtained was labeled as LL26, and it exhibited a correlation of optical density and base consumption that represented the highest level and the fastest time, respectively. Previously, this invention described how adaptive evolution was performed on JU15, which ferments xylose yielding 95% conversion to D-lactate; the results are mentioned above.
FIG. 30 compares the transferences of LL2(1) to LL2(7) in 40 g/L xylose fermentation conditions. The 7 th pass is a replica of the behavior of LL2(6); there is no improvement from pass 7 to pass 9 (data not shown), which is why pass 6 was selected as the evolved strain. As a control, the JU15 strain was used, and the behavior of the LL26 transferences is very similar. The inventors observed that the maximum consumption of 2 N KOH occurs in the interval from 12 h to 24 h for all of the strains. The consumption of the base is used to determine the growth of the strain and the consumption of xylose, given that it is a homofermentative strain, whose capacity for regenerating its reducing power is restricted to the production of L-lactate from xylose.
From cultures in glucose, it was observed that strain LL26 converts any carbon source to L-lactate with a yield near the theoretical value (>95%) and with a volumetric productivity of 1.17 g/L*h. For xylose, 95% conversion was observed, but the volumetric productivity was reduced to 0.68 g/L·h (see FIGS. 38 and 39 ).
Example 15
The Construction of an Ethanol-Generating Strain from Strain JU15A
Suppression of the IdhA Gene that Codes for the Lactate Dehydrogenase Enzyme
For the suppression of the IdhA gene in the E. coli strain JU15A, the inventors used the method described by Datsenko and Wanner (2000), which uses the λ phage Red recombination system to inactivate genes in the chromosome of E. coli with homologous recombination using linear PCR products.
The protocol for the suppression of the IdhA gene of E. coli strain JU15A ( E. coli MG1655 ΔpflB, ΔadhE, Δfrd, ΔxilFGH::Km R , resistant to acetic acid) using this method is described below.
When the inventors used the primers 716FWF (SEQ. ID NO: 17) and 717RVF (SEQ. ID NO: 18), they obtained a PCR product that consisted of the gene for resistance to chloramphenicol (cat) flanked by sequences homologous to the E. coli gene IdhA (see FIG. 31 ).
The PCR product was transformed by electroporation at 2,500 V into E. coli strain JU15A (pKD46). Next, 100 μL of the cells was seeded in LB and Cm 30 (μg/mL) medium to recover recombinant strains in which the IdhA gene was replaced by the Cm gene and flanked by the PS1 and PS2 sites. Thus, the strains recovered with resistance to Cm 30 were later analyzed by PCR to verify the suppression of the IdhA gene.
To phenotypically confirm that this recombination had taken place, several of the colonies obtained in the previous step and the control strain (JU15A, IdhA + ) were seeded in replicates in minimal M9 media with 20 g/L glucose and 30 mg/L Cm in aerobic conditions and in anaerobic systems at 37° C./24 h. The colonies were seeded in minimal medium and in anaerobic conditions to verify the suppression of the IdhA gene, as this was the only way that E. coli strain JU15A could regenerate reducing power (NAD + ) and survive metabolizing pure glucose in anaerobic conditions. Thus, the colonies that did not grow after 24 h in anaerobic conditions (IdhA − ) but that did grow in aerobic conditions were chosen for PCR analysis. To perform the PCRs for these strains and the control strain (JU15A), the primers 1189 FWF (SEQ ID NO: 19) and 1190 RVF (SEQ ID NO: 20) were designed, with approximately 20 bp homologous to regions located 200 bp before and after the IdhA gene. The PCR analysis was performed with these primers and the chromosomal DNA of the strains that did not grow in anaerobic conditions and were resistant to chloramphenicol. However, because of the size of the Cm gene insert and because the FRT and PS sites were very similar to the IdhA gene, the PCR products of strain IdhA − and of the control strain (JU15A, IdhA + ) only differed by 66 bp and could not be differentiated in agarose gels (data not shown). Through this analysis, a new primer was obtained that was homologous to an intermediate region of the Cm gene and, together with primer 1190 RVF (SEQ ID NO: 20), PCRs were once more performed on the chromosomal DNA of four colonies. Three of the colonies amplified a product of 522 bp, corresponding to the expected size using the Cm primer ( FIG. 32 ), which insured that these three colonies had the Cm gene inserted in place of the IdhA gene.
Suppression of the Cm Resistance Cassette
The PCR products of four colonies with the suppressed IdhA gene and without the chloramphenicol resistance gene in addition to the control strain JU15A (IdhA + ) are shown in FIG. 33 .
After isolating and identifying the colonies with suppressed IdhA and without resistance to chloramphenicol, they were seeded in LB media and stored in 40% glycerol at −70° C. This new strain was labeled E. coli MS01 with the genotype (ΔpflB, ΔadhE, Δfrd, ΔxilFGH::Km R , ΔIdhA); it is incapable of growing in anaerobic conditions in mineral media and with glucose as the only carbon source.
Insertion of the pdc and adhB Z. mobilis Genes in E. coli MS01 under the Promoter Control of pflB.
The inserted pdc and adhB Z. mobilis genes were intended to be under the control of the promoter of pflB, which is strongly expressed in anaerobic conditions in E. coli , thus yielding a good level of the transcripts for these genes for the production of ethanol in anaerobiosis.
Strain MS01 (ΔpflB, ΔadhE, Δfrd, ΔxilFGH::Km R , ΔIdhA, acetate resistant) has the pflB gene suppressed, so primers were designed with homology for several by before and after the pflB gene to amplify and sequence this region of the pflB gene and determine whether the sequences of its promoters were intact. The primers used to generate the PCR of this region were the primers 4166 (SEQ ID NO: 21) and 4167 (SEQ ID NO: 22).
Once the PCR product of the region before/after the gene pflB had been obtained (569 bp), it was sent for sequencing, and the sequencing results show that the method used to suppress pflB did not affect the promoter region of this gene and that 30 bp from the start codon (ATG) to the stop codon (TAA) remained as shown in the sequence below.
Sequencing of the pflB Gene Region:
(SEQ ID NO: 25)
5′-tac gca gta aat aaa aaa tcc act taa gaa ggt agg
tgt tac ATG TCC GAG CAA GCT TCT CAA
TCT ATG TAA tta gat ttg act gaa atc gta cag taa
aaa gcg tac aat-3′.
In the prior sequence (SEQ ID NO:25), the codons in capital letters represent the 30 bp of the pflB gene with a suppression sequence for Hind III, whereas the codons in lowercase letters show the regions approximately 40 bp before the start codon (ATG) and after the stop codon (TAA) of the pflB gene, which do not affect the promoter region of this gene (Sawers and Bock, 1989).
Using the data from the prior sequence, the inventors sought to insert the Z. mobilis pdc and adhB genes under the control of the promoter sequence for the E. coli MS01 gene pflB through double homologous recombination, exchanging those two genes with the leftover region of the pflB gene (the capital letter codons of the pflB sequence). To this end, the A phage Red recombination system was used again, with the methodology previously described, to modify strain MS01. According to this system, cells of E. coli strain MS01 were made chemocompetent, transformed with the pKD46 plasmid, isolated and selected for resistance to ampicillin (Amp 100). Afterward, the cells were cultured in SOB media with arabinose (1 mM) to induce the Red recombination system, and after they were made electrocompetent, they were electroporated with a PCR product that contained the two genes (pdc and adhB) in tandem flanked by regions homologous to the pflB gene. The primers designed to amplify this PCR product were 4512 FWF (SEQ ID NO: 23) and 4513 RVF (SEQ ID NO: 24). These primers, along with the purified pLO1510 plasmid, were used to generate a PCR product that amplified the two pLO1510 plasmid genes in tandem (pdc and adhB). These primers included the homologous sequences immediately before and after the pflB gene of E. coli MS01 that were used as sequences to conduct the double homologous recombination mediated by the Red recombination system of pKD46. Thus, the pdc and adhB genes were inserted under the pflB promoter in the MS01 strain. The PCR product digested with Dpnl and purified with agarose (1%) gel electrophoresis is shown in FIG. 34 .
The PCR product was transformed into strain MS01 (pKD46) by electroporation, and the cells were allowed to recover immediately afterward in SOC media (1 mL) for 12 h at 30 and 37° C., as the cells previously recovered at 37° C. for 2 h did not yield any colonies. Thus, future samples were incubated in anaerobic conditions and without shaking for a longer time at these two temperatures so that only the cells that had assimilated the pdc and adhB could be selected and grown. After 12 h of incubation at 30 and 37° C., 200 μL of each culture was inoculated in mineral medium with glucose (20 g/L) and Km 40 and incubated at 37° C. for 48 h in aerobic conditions to isolate colonies that had assimilated the pdc and adhB genes. Only the transformed cells would be capable of growing in anaerobic conditions because they would have a new pathway to regenerate reducing power (NAD + ) and to survive under such conditions. After 48 h of incubation, several colonies were recovered, mainly those that had been incubated at 30° C. in SOC media; however, after isolating them and reseeding them in the same medium in anaerobic conditions, they grew much faster.
In this way, three colonies were selected for PCR analysis, along with the control strain MS01, using the primers 4166 FWF and 4167 RVF, which amplify a region 250 bp before and after pf/B, yielding PCR products of 3,361 bp for the strains transformed with Z. Mobilis pdc and adhB genes and 569 bp for the control strain MS01, which has suppression of pflB ( FIG. 35 ).
Once the insertion of the pdc and adhB genes in the colonies had been determined phenotypically by growth in anaerobic conditions and genotypically by PCR, this strain was labeled as E. coli MS02 (ΔpflB, ΔadhE, Δfrd, ΔxilFGH::Km R , ΔIdhA, PpflB::pdc Zm -adhB Zm , resistant to acetic acid), (see FIG. 41 ) which produces ethanol, in contrast to strain MS01.
Subsequently, the E. coli strain MS02 was subjected to a process of adaptive evolution in AM2 mineral medium with glucose or xylose (50 g/L) supplemented with sodium acetate (2.05 g/L), with several passages performed when the cells were in the exponential growth phase. The strain obtained after the process of adaptive evolution was labeled E. coli MS04, and this strain was able to grow in glucose and xylose in the presence of acetic acid, producing ethanol (See FIGS. 36 and 37 ).
Kinetic Parameters of E. coli MS01 Strain in AM2 Medium with Glucose, Xylose (50 g/L) or a Glucose-Xylose Mixture (7.5-42.5) All of Them with Acetate (2.05 g/L).
Parameter
E. coli
(exponential growth
MS04 -
E. coli MS04 -
E. coli MS04 -
phase)
Glucose
Xylose
Glucose-Xylose
μ (h −1 )
0.3
0.26
0.25
qs (gsubst/gcel mass h)
3
3.3
2.85
qp (gEtOH/gcel mass h)
1.1
0.6
0.7
Yps (% Theor. max.)
92
92
93
Vol. Prod
0.67
0.65
0.65
(gEtOH/L h)
Example 15
Ethanol Production from Rapid-Growth Grass Hydrolysates Using the Strain E. coli MS04 Derived from JU15
The inventors of the present invention conducted ethanol production using strain E. coli MS04 (NRRL B-50138), which was derived from E. coli JU15 (NRRL B-50140), using sugars from the thermochemical hydrolysis of the rapid-growth grass Paspalum fasciculatum . This grass grows naturally in several regions in southeast Mexico and has not been previously reported for use in the production of ethanol. Other rapid-growth grasses, such as elephant grass or switchgrass, have been proposed in the United States and in several countries of the European Union as raw materials to hydrolyze and to generate sugars that can be fermented into ethanol. However, no experiments have been conducted in Latin America to use rapid-growth grass in the production of second-generation ethanol.
In this invention, grass collected from the Tabasco region was dried in sunlight. The material was characterized as having 15-25% xylan, 30-40% glucan, 2-3% arabinan, 2.5-3.5% acetate, 12-16% lignin and 1-3% ashes, with the remainder consisting of extractive material. The hemicellulose fraction of the grass was hydrolyzed via a thermochemical method at 121° C. using sulfuric acid with different concentrations (1, 2 and 4% w/w), times (10, 30 and 60 min) and reaction conditions (3 biomass to liquid ratios, 1:2, 1:5 and 1:10). A syrup was generated to test the fermentation ability of the E. coli strain MS04 (NRRL B-50138), which was derived from JU15 (NRRL B-50140). The syrup used had a mean level of 28.8 g/L of sugars, primarily xylose (5.5 g/L glucose, 19.6 g/L xylose and 3.7 g/L arabinose), 6.2 g/L acetate and a small amount of furans. The syrup was treated with calcium hydroxide, neutralized and supplemented with salts to ferment the sugars present within. The cultures were carried out in mini-fermenters with operation volumes of 200 mL at a temperature of 37° C. and a pH of 7, with the last value controlled by the automatic addition of 2 N KOH. FIG. 42 shows the results of the ethanol production; this example had a yield of 95% of the theoretical value for the sugar-to-ethanol conversion, converting practically all of the sugars into ethanol in 36 h.
Example 16
Ethanol Production from Agave Bagasse Hydrolysates Using the E. coli MS04 Strain Derived from JU15
The inventors of the present invention carried out the production of ethanol using the E. coli strain MS04 (NRRL B-50138), which was derived from E. coli JU15 (NRRL B-50140), using sugars from the thermochemical hydrolysis of agave bagasse obtained from blue agave distillate production plants. Agave bagasse is a factory waste product of tequila, mezcal and other spirits distilled in several regions of Mexico and now in other Latin American and African countries. This material is essentially lignocellulose and does not have any practical applications in distillation factories because it cannot be used as fuel, and it is a potential alternative source of five- and six-carbon sugars that can be fermented by the microorganisms that are the focus of the present invention patent.
Blue agave bagasse, collected from an agave distillate factory in the southern region of Morelos, Mexico, was dried in sunlight. The material was characterized as having 12-18% xylan, 35-45% glucan, 3-5% acetate, 22-30% lignin and 2,5-5.5% of ashes, with the remainder consisting of extractive material. The hemicellulose fraction of the agave bagasse was hydrolyzed via a thermochemical method using sulfuric acid at different concentrations and reaction conditions. The syrup was treated with calcium hydroxide, neutralized and supplemented with salts to ferment the sugars present within. A syrup rich in xylose that also contained glucose and arabinose was generated, which was concentrated until a level 51 g/L of total sugars was obtained, including 87.5% xylose, 8.8% glucose and 3.7% arabinose. This syrup also contained 0.2 g/L of hydroxymethyl-furfural, 0.2 g/L of furfural and 20.3 g/L of acetate. The syrup was fermented in a bioreactor with a 1-L operating volume at a temperature of 37° C., with shaking at 360 rpm and a pH of 7 controlled by the automatic addition of 2 N KOH, using the E. coli MS04 strain (NRRL B-50138), which was derived from JU15 (NRRL B-50140). The results obtained in this last example of the present invention indicate that the conversion efficiency of the sugars into ethanol was 85% of the theoretical value after 61 h of fermentation; see FIG. 43 .
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The present invention refers to the new Escherichia coli strains denominated JU15, JU15A, LL26 and MS04 and their derivatives that produce metabolites, particularly D-lactate, L-lactate or ethanol, with high yield and selectivity from a wide variety of carbon sources, such as culture media with a high xylose content (as the main carbon source) and, in particular, media formulated with hydrolyzed vegetables, such as sugarcane bagasse, agave bagasse and fast-growing grasses, and a wide variety of agricultural and industrial wastes, such as whey or forestry wastes, celluloses, grasses, agave bagasse, paper wastes, shavings and sawdust, shrubs and generally any material derived from lignocellulose. These strains use the production of the metabolite of interest (especially D-lactate, L-lactate or ethanol) as the only way of regenerating the reducing power. The invention also refers to fermentation methods to produce these metabolites from media with a diversity of carbon sources, including glucose, lactose or xylose.
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FIELD OF THE INVENTION
The invention relates to a tension element for a ski boot fastener, comprising a wire, i.e. cable, which is formed into a loop and is surrounded at least partly with a flexible plastic and the ends of which are connected with one another by a tube-shaped compressed-lock element and at one end of the loop there is provided a substantially U-shaped clasp of a rigid material for hanging on a tensioning lever which is mounted on the ski boot and a connecting means for connecting the loop to the ski boot engages the second end of the loop.
BACKGROUND OF THE INVENTION
Such known locking elements consist mostly only of a cable made of steel, which is bent to form a loop. The ends of the cable are held together by a tube-shaped compressed-lock element. For this purpose, the ends of the cable are inserted into the compressed-lock element, same is then pressed together and mostly in addition bent. By bending the compressed-lock element into a U-shape, the compressed-lock element forms simultaneously a U-shaped clasp, which can be hung on the tensioning lever of the ski boot. Many times in conventional tension elements the cable is additionally surrounded by a tube of plastic.
These conventional tension elements, however, do not lend the ski boot which is made of plastic a pleasant appearance and furthermore increase the price of its manufacture. Namely channels and guideways are needed on the ski boot, in order for the loops to be held in the correct position on the ski boot. The channels and guideways which are necessary on the ski boot itself increase the price of manufacture of the ski boot because three to five tension elements must be mounted on every pair of ski boots and the channels and guideways must therefore be worked into the injection mold which is used for the manufacture of the ski boot. It must hereby be considered that at least two injection molds are needed for each boot size.
The basic purpose of the invention is to produce a tension element for a ski boot fastener of the above-mentioned type, which maintains the flexible characteristics of the up to now used tension element, however, does not need any guideways and channels on the ski boot so that the injection mold for the manufacture of the ski boot is simplified and furthermore the appearance of the ski boot is improved.
This purpose is attained according to the invention by the cable loop being arranged substantially inside of a plastic band which extends to the clasp such that the cable pieces which are provided between the ends extend substantially parallel and spaced from one another and by the space which lies between the cable pieces being filled with plastic, which also surrounds the cable pieces and forms a web between same.
The plastic band gives the tension element a certain rigidity in the plane of the tension element. In spite of this, however, the tension element remains still sufficiently flexible transversely to the plane so that it adapts to the form of the ski boot. Due to the stiffness of the tension element, or flexible strap, in transverse direction, channels or guideways do not need to be provided on the ski boot. As a result, the injection mold is simplified and the manufacture of the ski boot becomes less expensive. Furthermore the ski boot has a better appearance, especially since the cable loop is enclosed totally or almost totally by the plastic of the band. The cable is also protected against any damage by the plastic. Furthermore high tension forces can be transmitted with the new tension element, without fearing any damage.
The plastic band has preferably at its second end a hole to receive a rivet therethrough which serves as a joint and the cable loop is arranged near the hole in the band and surrounds approximately half of the hole. Through this design of the tension element, the problem of fastening of the tension element in the area of the ankle of the ski boot is solved. Up to now it has namely always been problematic to provide in the ankle area a fastening for a tension element. The rivet joint serves now at the same time for fastening the tension element and for the hingelike connection of the upper part of the ski boot to the lower part of the ski boot. Since the cable loop is arranged near the edge of the hole, the tension forces are transmitted directly from the cable loop onto the rivet joint.
BRIEF DESCRIPTION OF THE DRAWINGS
Further details and advantages of the invention are discussed more in detail hereinafter with reference to several exemplary embodiments which are illustrated in the drawings, in which:
FIG. 1 is a diagrammatic illustration of a first exemplary embodiment of the inventive tension element,
FIG. 2 is a partially sectional top view of the tension element,
FIG. 3 illustrates a ski boot with several tension elements,
FIG. 4 is a cross-sectional view along the line IV--IV of FIG. 2 or 5,
FIG. 5 is the bottom view of a second exemplary embodiment,
FIG. 6 is a cross-sectional view along the line VI--VI of FIG. 5,
FIG. 7 is a partial side view of this exemplary embodiment,
FIG. 8 is a partial top view of a third exemplary embodiment,
FIG. 9 is a top view of a fourth exemplary embodiment.
DETAILED DESCRIPTION
The cable which consists of steel is bent to form a loop. The ends 1a of this cable are placed into a tube 2, which consists also of steel. This tube is strongly compressed after the ends 1a have been placed into the tube, so that the ends 1a can no longer be removed from the tube 2. The tube 2 forms thus a compressed-lock element. The tube 2 is furthermore bent into a U-shape and serves therefore also as a clasp for hanging into various hooks 3 of a tensioning lever 4, the bearing plate 5 of which is secured on a ski boot.
The cable loop 1 is encased substantially inside of a plastic band 7 which consists of a thermoplastic, flexible plastic and only the tube 2 which is provided at the one end of the plastic band projects from the plastic. The second end 1b of the cable loop 1 is arranged near an edge 6a of a hole 6 which is provided in the plastic band. The end 1b of the loop 1 surrounds approximately half of the hole 6. The hole 6 serves for a passage of a larger rivet 8, which is used for the hingelike connection of the upper part 9 of the ski boot 11 to the lower part 10. At the same time, however, the rivet joint 8 serves to connect the resulting tension element, or flexible strap, 12 to the ski boot. Since the cable 1 is arranged at the edge 6a of the hole 6, the tension forces are transmitted directly from the part 1b of the wire 1 onto the rivet joint 8 and from same onto the ski boot. The two cable pieces 1c which extend between the one end which is formed by the tube 2 and the other end 1b of the cable loop 1 extend substantially parallel to one another and are laterally spaced from one another. The lateral spacing between the cable pieces 1c is also filled in with plastic, which also surrounds the cable pieces 1c and forms a web 7a therebetween. The plastic band 7 lends the cable loop 1 a certain rigidity in its plane and the entire tension element has still transversely to the plane of the cable loop the desired flexibility.
In the exemplary embodiment which is illustrated in FIGS. 5 to 7, the compressed-lock element 13 which consists also of a steel tube is bent substantially V-shaped and it surrounds with its part 13a the edge 6a of a hole 6. The cable loop 1, like in the first exemplary embodiment, is embedded in the plastic band 7 and the cable pieces 1c are arranged parallel to one another and are laterally spaced from one another. The cross section of this exemplary embodiment corresponds with the cross section illustrated in FIG. 4. To connect the wire loop 1 to the clasp 14, which like in the first exemplary embodiment can be hung into a tension lever 4, a holding plate 15 is used, on which the clasp 14 is pivotally supported. The holding plate 15 has means 16 for hanging up the one end of the loop 1. The hanging means 16 and the larger portion of the holding plate 15 are encased by the plastic of the band 7. The hanging means 16 are each formed by a flap which is punched out on each longitudinal side of the holding plate and bent semicircularly with respect to the plane of the holding plate. This flap forms a channel and opens toward one side of the plate. Each one of the flaps, however, extends only over approximately half of the longitudinal side of the holding plate 15. The cable loop 1 is placed into the channels of the flaps 16 and extends then over the upper side of the plate 15. The holding plate 15 furthermore has holes 17, which are also filled with plastic so that the plastic parts are connected on both sides of the holding plate. The tension element 18 which is illustrated in FIGS. 5-7 is also secured to the ski boot with a rivet joint which is also not illustrated.
The tension element 19 which is illustrated in FIG. 8 is designed on the one side just like the tension element 18. It has there also a holding plate 15 and a clasp 14. These parts are, however, not illustrated in the drawings. The other end of the tension element 19, which is fixedly connected to the ski boot, is illustrated in FIG. 8. The compressed-lock element 20 with which the ends of the cable loop 1 are connected, is hereby bent into a U-shape. Only a small part of this compressed-lock element 20 projects from the plastic band 7. A fastening flap 21 is hinged to the projecting U-bar 20a of the compressed-lock element 20. The fastening flap 21 is secured by means of two not illustrated rivets on the ski boot.
A further exemplary embodiment is illustrated in FIG. 9. The cable loop 1 is encased by the plastic band 7 hereby in a similar manner as in the preceding exemplary embodiment. A U-shaped clasp 22 is hinged to the one end of the cable loop 1, which clasp can serve to hang in the tensioning lever. The U-shaped clasp 22 can be formed by a tube which is pulled over the cable. The compressed-lock element 24 is arranged at the other end of the tension element 23, which compressed-lock element is also bent into a U-shape. A fastening plate 25 is hinged to the compressed-lock element 25, which fastening plate is used to fasten the tension element 23 to the ski boot. Of course, the arrangement can also be such, that the compressed-lock element, similar to the exemplary embodiment illustrated in FIGS. 1 and 2, is arranged on the end of the tension element 23, which also engages the tensioning lever. In this case, a U-shaped bent tube is then provided at the other end and the fastening plate 25 is engaged therewith.
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A tension element for a ski boot fastener having a wire, i.e. cable, formed into a U-shape. The ends of the cable are received in a tube also bent into a U-shape. The ends of the tube are compressed onto the cable to effect a securement therebetween. The tube defines a clasp receivable in the hooks provided on a tension lever. The loop so formed is at least partly encased in plastic, the plastic material forming a web between the cable pieces forming the sides of the loop.
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BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for producing a monocrystal. It more particularly applies to producing monocrystals which can be used as scintillators and more specifically to the production of BaF 2 barium fluoride monocrystals.
Monocrystal production processes are known, the most frequently used being the BRIDGMAN process. In this case, the material to be crystallized is placed in a crucible, which is displaced in a small temperature gradient from a high temperature zone to a low temperature zone. The smallness of the temperature gradient makes it indispensable to previously purify the material, which is generally carried out by the method known as "zone fusion". According to this method, only part of an ingot of the material to be purified is heated, thus forming a thin fusion layer and said layer is then moved from one end of the ingot to the other, the impurities contained in this ingot then being displaced towards one end thereof. This operation has to be repeated a number of times to obtain a very pure material. Moreover, the use of a very abrupt temperature gradient causes the ingot to break up into several pieces, which are unstable as a result of their small size. The BRIDGMAN process is then applied thereto in order to obtain a monocrystal of an appropriate size.
The procedure associating the zone fusion method and the BRIDGMAN process suffers from disadvantages. The procedure is long and complex and requires several manipulations of the material to be crystallized, which increases the risks of pollution thereof, which must obviously be prevented, particularly in the case of crystals for use in the production of scintillators.
SUMMARY OF THE INVENTION
The object of the present invention is an apparatus for producing a monocrystal, which does not suffer the disadvantages of the previously described procedure, namely in that it is very simple, making it possible to obtain relatively high monocrystal growth rates of 2 to 10 mm/hour for example, requires few manipulations of the material to be crystallized and consequently obviates any risk of pollution thereof. Moreover, it can be completely automated and makes it possible to obtain crystals as required in single form or several crystals at once, which can have all the desired shapes (cylindrical, parallelepipedic, etc.).
More specifically, the present invention relates to an apparatus for producing a monocrystal from a crystallizable material, wherein it comprises at least one thermally conductive crucible for receiving the material, a thermally conductive means having a part able to receive each crucible and extended by a projection, means for heating the thermally conductive means and each crucible containing the material, means for the relative displacement of the thermally conductive means and each crucible containing the material with respect to the said heating means and crystallization means able to bring about the crystallization of one end of the material melted in the heating means, once said end has been extracted therefrom, and wherein the projection is positioned so as to check the temperature gradient undergone by the material during the relative displacement.
The heating means are designed to bring about an abrupt temperature reduction of the material heated by them, when it is extracted therefrom by the displacement means. The thermally conductive material checks the temperature reduction of the material melted by the heating means. The relative displacement means make the material undergo a controlled temperature gradient and ensure that the material is crystalline, the latter then being slowly cooled to ambient temperature.
"Slow cooling" is understood to mean cooling not exceeding a few hundred degrees celsius per hour, e.g. a cooling of approximately 50° to 100° C./h. "Abrupt temperature reduction" is understood to mean a reduction of the type obtained in the zone fusion method known from the prior art.
Obviously, the thermally conductive means can be displaced relative to the heating means or, conversely, the latter can be displaced relative to the thermally conductive means.
In the present invention, the thermally conductive means is fundamental. By heat conduction, it makes it possible to homogenize the temperature of the material and attenuate the abrupt temperature reduction which can also be called the "abrupt temperature gradient". The temperature gradient undergone by the material can be modified at random by modifying the shape and/or the nature of the thermally conductive means.
Thus, according to the invention, the material is melted in the heating means and then, by displacement, emerges at one end thereof. At this end, the material undergoes a temperature reduction and a liquid--solid interface appears in the material. The temperature reduction is sufficiently high to bring about a rejection of all the impurities of the material in its liquid part and consequently to purify the same and is sufficiently attenuated by the thermally conductive means to permit a continuous monocrystalline growth of the material as it emerges from the heating means. This monocrystalline growth is initiated by the end of the material emerging first from the heating means.
Thus, the present invention corresponds to an intermediate procedure between the BRIDGMAN process and the zone fusion method, whilst leading to the results obtained by both these methods, namely the purification of the material and the obtaining of a monocrystal of said material having an appropriate size.
According to a special feature of the invention, the bottom of each crucible is tapered, so as to constitute the crystallization means.
According to another special feature, the apparatus according to the invention comprises a plurality of crucibles, the thermally conductive means having a cavity, whilst the crucibles are arranged symmetrically around said cavity. This obviates local overheating of the thermally conductive means.
According to another preferred feature of the apparatus according to the invention, the thermally conductive means and each crucible are made from purified graphite.
According to another preferred feature, the heating means comprise high frequency field windings. Instead of these, it could also have Joule effect-heated resistive windings, but the resulting heating would then be less homogeneous due to a higher radial gradient.
According to another special feature, the assembly constituted by the thermally conductive means, each crucible and the material is placed in an enclosure insulating it from the outside atmosphere.
Finally, and preferably, the apparatus according to the invention may also comprise means for circulating a chemically inert gas in such a way as to produce the monocrystal in a chemically inert atmosphere.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described in greater detail hereinafter relative to non-limitative embodiments and with reference to the attached drawings, wherein show:
FIG. 1 is a diagrammatic view of a special embodiment of the apparatus according to the invention.
FIGS. 2a to 2d are diagrammatic cross-sectional views of embodiments of the thermally conductive means and the crucibles used in the invention.
FIGS. 3a to 3c are graphs showing the differences between the invention and the BRIDGMAN and zone fusion methods.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 diagrammatically shows a special embodiment of the apparatus according to the invention. It essentially comprises a thermally conductive means 2 able to contain at least one crucible 27 filled with the material 28 to be crystallized, heating means 3, means 4 for the displacement of the thermally conductive means 2 relative to the heating means 3 and crystallization means 5 able to initiate the crystallization of the material, when it is extracted from the heating means 3.
In this case, heating means 3 surrounding a quartz tube 6 of axis Z and which is vertically arranged, comprise high frequency field windings 7, which only surround a portion of tube 6 and which are supplied by a high frequency current generator 8.
The upper or lower end of tube 6 is provided with an O-ring 9 or 10 and is sealed by a threaded plug 11 or 12 on the outside and is in contact with one side of the O-ring, as well as by a ring 13 or 14 threaded on the inside and in contact with the other side of the O-ring, the plug being screwed into the ring so as to compress the joint.
The interior 15 or 16 of each plug 11 or 12 is hollowed out so as to permit the circulation of a cooling fluid introduced by a pipe 15a or 16a into the plug 11 or 12 and discharged by a pipe 15b or 16b from the interior of said plug.
Moreover, a circulation of a chemically inert gas such as argon is established within tube 6. The argon is introduced into the latter by a pipe 17 traversing the lower plug 12 and is discharged from tube 6 by pipe 18 traversing the upper plug 11 and leading to not shown pumping means. Prior to its introduction into tube 6, any trace of water is removed from the argon by making it e.g. circulate in a resistance furnace 19 communicating with pipe 17 for the introduction of the argon into tube 6. The furnace 19 contains fragments 20 of material marketed under the tradename Teflon (polytetrafluoroethylene) which, when heated, decomposes to give carbon tetrafluoride which fixes the water molecules.
The displacement means 4 comprise a rod 21 which traverses the lower plug 12 and is vertically displaceable in tube 6 along axis Z, said rod 21 being controlled by a translation mechanism 22.
The thermally conductive means 2 is designed to be vertically displaceable along axis Z in tube 6 and has an upper part 23, which is on the underside extended by a projection 24, which is provided at its base with a slot 25 in which is fixed rod 21. The upper part 23 of the thermally conductive means 2 has several parallel, vertical recesses 26, which issue at the apex of said upper part 23 and which are designed to receive the crucibles 27 for containing in each case the material 28 to be crystallized. The thermally conductive means 2, which will now be called the crucible support, is displaced in tube 6 from an upper position A in which all the material contained in the different crucibles 27 is within the zone defined by windings 7, which have a length provided for this purpose, to a lower position B in which only the apex of the crucible support 2 is then located within said zone. Preferably the crucibles support 2 and the crucible 27 are made from so-called "nuclear" graphite.
In per se known manner, the bottom of each crucible has a substantially conical tapered shape suitable for the formation of a monocrystalline nucleus of the material contained in the crucible when said material, melted in the heating means, solidifies on leaving the latter. Thus, the bottom of each crucible forms the said crystallization means 5.
The process for producing monocrystals carried out in the apparatus described hereinbefore with regards to FIG. 1 will now be explained. The crucibles 27, filled with the material to be crystallized, are placed in the crucible support 2, which is in the upper position in tube 6. Argon is then circulated in the latter at a rate of approximately 4 liters/minute for example and the resistance furnace 19 is started up. When the latter has reached a temperature of approximately 460° C., (which permits the decomposition of the Teflon (polytetrafluoroethylene) contained in this furnace), the temperature of the assembly constituted by crucible support 2 and the crucibles 27 containing the material to be crystallized is raised in such a way that the assembly is raised to a temperature exceeding, by 20° C., the fusion temperature of the material in question. The assembly is kept in the heating means for an adequate time, e.g. roughly one hour, to have a good temperature homogeneity in the assembly, so that the material is in the molten state.
A downward translation of the crucible support is then brought about, the translation speed being a function of the material to be crystallized, the shape of the crucible support 2 and the number of crucibles used. Thus, a higher speed is used with one crucible than several.
When the crucibles leave the heating zone defined by winding 7, the material at the bottom of the crucibles undergoes a large temperature gradient, which is attenuated by the crucible support 2 and then a monocrystalline nucleus is formed. The lowering of crucible support 2 continues, the formation of a monocrystal in each crucible continues, but the temperature variation undergone by the material leaving the heating zone is sufficient for the impurities contained in the material to diffuse towards the top thereof.
At the end of the translation, corresponding to the bottom position B of the crucible support 2, the monocrystals of the material have been produced and this is followed by slow cooling, with a speed of e.g. approximately 50° to 100° C./hour of the assembly constituted by crucible support 2, crucibles 27 and the material contained in the latter, by acting on the power of high frequency generator 8, until the assembly reaches ambient temperature (approximately 20° C.). High frequency generator 8 and resistance furnace 19 are then stopped and the monocrystals are extracted from crucibles 27. These monocrystals are in the form of ingots, whose upper end containing the impurities initially distributed throughout the material is then cut off.
It should be noted that the automatic operation of the apparatus according to the invention shown in FIG. 1 is total as from the time of starting up the translation of crucible support 2.
The process described hereinbefore is particularly applicable to the production of barium fluoride monocrystals. Under excitation, this material is subject to a light emission which has a slow component and a fast component and, for forming a high quality scintillator material, must be purified so as to reduce the defects of its crystal lattice, in order to increase the intensity of the fast component.
The barium fluoride is then introduced into crucibles 27, e.g. in powder form. In a non-limitative manner, in the case of barium fluoride, the assembly constituted by the crucible support, the crucibles and the barium fluoride contained therein is raised by the heating means 3 to temperatures of approximately 1380° C. and a crucible support translation speed between 1 and 10 mm/hour is used. For example, three crucibles, a speed of approximately 5 mm/hour is suitable.
It should be noted that the mould removal of the barium fluoride monocrystals obtained is easy, in view of the fact that this material undergoes a contraction during its crystallization.
As a result of the present invention, it is possible to simultaneously produce several monocrystals and give very varied shapes thereto. For this purpose it is merely necessary to give the crucibles the required shape. This is shown in FIGS. 2a to 2d, in which it is possible to see crucibles 27 regularly positioned in crucible supports 2 and which have square, rectangular, triangular and elliptical cross-sections. For example, the invention makes it possible to produce monocrystals having a square cross-section with 26 mm sides and 120 mm length, in three crucibles maintained in a cylindrical crucible support of diameter 130 mm.
In the case where several crucibles 27 are simultaneously used, the upper part 23 of the crucible support 2 can be centrally provided with a cavity 29, the recesses 26 for receiving the crucibles 27 then being symmetrically distributed around said cavity 29, as is shown in FIGS. 2b and 2d. Cavity 29 makes it possible to obtain a better temperature homogeneity by preventing overheating in the centre of part 23.
The different possible shapes of the monocrystals to be produced can lead to a non-uniform temperature distribution in each cross-section of said monocrystals. This can easily be compensated by a modification of the shape and/or nature of the crucible support 2 and/or the type of high frequency heating (skin effect). By proceeding in this way and as a result of high frequency heating (i.e. by high frequency field windings), the material to be crystallized can be heated uniformly at all points, no matter what its shape. Resistive heating (using Joule effect-heated resistive windings) is possible, but is less homogeneous than high frequency heating for the assembly constituted by the crucible support and the crucibles containing the material to be crystallized.
It has been stated hereinbefore that the initial position of the crucible support 2 is such that the material to be crystallized is initially located in the zone defined by windings 7. Obviously, the initial position of the crucible support could be higher in tube 6, the material to be crystallized then initially being located outside the heating zone defined by windings 7, but the time for producing the crystals would then be longer.
FIGS. 3a, 3b and 3c are graphs giving the temperature T as a function of the position on axis Z for a material to be crystallized, to which is respectively applied the BRIDGMAN process (FIG. 3a), the zone fusion method (FIG. 3b) and a process using the apparatus according to the invention (FIG. 3c).
In the BRIDGMAN process, the temperature gradient undergone by the material to be crystallized is small and there is no question of using a crucible support for attenuating this gradient. In the zone fusion method, the heating of the material is very localized and the temperature gradient undergone by the material is very sudden. In the present invention, use is made of a crucible support for homogenizing the temperature of the material and for attempting the abrupt temperature gradient produced by the heating means and which would only produce a purification effect of the material if it was not attenuated.
In other words, the temperature gradient undergone by the material in the present invention is intermediate between the temperature gradient which it would undergo in the BRIDGMAN process and the temperature gradient which it would undergo in the zone fusion method.
Moreover, on e.g. producing a barium fluoride monocrystal with the apparatus according to the invention, the results obtained are much better than those by firstly using the zone fusion method and then the BRIDGMAN process on the barium fluoride. Thus, a barium fluoride monocrystal produced by means of the invention has a light emission, whose fast component has an intensity which is increased compared with the slow component to a greater extent than the fast component of a barium fluoride monocrystal obtained by successively applying the zone fusion method and the BRIDGMAN process to said barium fluoride.
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According to the invention, an apparatus for producing a monocrystal comprises at least one thermally conductive crucible for receiving the material, a thermally conductive holder having a part able to receive each crucible and extended by a projection, a heater for heating the thermally conductive holder and each crucible containing the material, a drive for the relative displacement of the thermally conductive holder and each crucible containing the material with respect to the said heater and a crystalizer able to bring about the crystallization of one end of the material melted in the heater, once said end has been extracted therefrom, and wherein the projection is positioned so as to check the temperature gradient undergone by the material during the relative displacement.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to rocket engine combustion chambers and more particularly to the method of assembling a structural jacket and a coolant liner.
2. Description of the Related Art
The function of a rocket engine main combustion chamber is to contain the combustion process (typically at 5000° to 6000° F. at 1000 to 4000 pounds per square inch pressure) and then accelerate the combustion products to a high velocity and exhaust them to create thrust. Typically, the combustion process takes place subsonically in the combustion chamber. The subsonic combustion gases are then accelerated through a converging/diverging DeLaval-type nozzle/venturi.
The combustion chamber typically consists of a monocoque structure to contain the combustion pressure, a cooled liner to protect the pressure vessel from the hot combustion gases, and manifolding required to circulate the coolant. Because of its inherent hourglass shape, combustion chambers are typically fabricated by starting with the coolant liner and building the pressure vessel jacket and manifolding around its external hourglass contour or starting with the pressure vessel and manifolding structure and building the coolant liner inside its internal hourglass contour. Materials of construction typically consist of copper base alloys for the coolant liner because of their high thermal conductivity and nickel-base alloys for the pressure vessel jacket and manifolds because of their high specific strength.
Currently, there are several methods of making combustion chambers with coolant channels. All of the methods in use today involve many fabrication steps each of which require critical inspections and possible rework if flawed. These processes are time consuming and expensive.
In one method, a coolant liner is machined from a billet of material. Coolant passage slots are machined on the outside of the liner. The coolant passages are then closed out using a plating process. The plating process is very labor-intensive, requiring several critical operations and is fraught with problems which can cause a considerable amount of rework in a typical chamber.
During the channel closeout process, the liner slots are filled with a wax material. The outer exposed surface is then burnished with a silver powder which forms a conductive plateable surface. On that surface, a layer of copper is electroplated, which is then followed by a build up of nickel to form a structural closeout to contain the coolant pressure. The nickel close out requires several plating cycles and several intermediate machining steps. All of the plating operations are plagued by problems such as contamination, plating solution chemistry, and other process parameters that can lead to poor bonding of the plated material. If anything goes wrong during this process, the plated material on the liner has to be machined back and the plating process repeated. Using this technique requires considerable time and labor to close out a liner.
Following the plating operations, the wax material must then be removed from the liner. This is a critical process, since any residual wax material can lead to contamination problems in subsequent operations.
When the liner is completed, the next step is to weld the inlet and outlet coolant manifolds to the liner structure. Local areas on the liner need to be built up with a considerable amount of electrodeposited nickel and machined backed to form a surface that can accommodate the weld joints. The manifolds are then welded onto the closed-out liner. Then the structural jacket, which is made up of several pieces, is assembled around the outside of the liner and manifold subassembly and welded in place. All of the weld joints are critical and require inspections. Any flaws found must be reworked. A typical combustion chamber may require as many as 100 critical welds. The process is very costly and time consuming. Utilizing this process, a complete main combustion chamber can take three (3) years to fabricate.
Another main combustion chamber fabrication method utilizes a "platelet" liner concept. In this method, the liner itself is made up of a stack of 15 to 20 very thin plates which are photochemically etched to form coolant slots, individually plated, stacked together, and then bonded to form a panel section of the liner with closed-out coolant passages. Any one of the plating processes or the bonding processes can form a bad joint, which would be reason to scrap the part. Typically seven or more individual panels are required to form an hourglass-shaped liner. The individual panels are installed inside the structural jacket. Since a joint is required between each of the adjacent panels, there are several locations for potential hot-gas leakage between the panels. All the joints must be sealed along the entire length of the combustion chamber. Also, all of the panels once installed, have to be bonded to the outer structural jacket. In order to bond the panels to the outer structural jacket, pressure bags are fabricated to match the contour of the thrust chamber. The bags are installed inside the thrust chamber liner along with backup tooling to support the pressure bags. The chamber and tooling are placed into a brazing furnace and brought up to temperature while the pressure is maintained in the pressure bags, which forces the liner into intimate contact with the jacket. If all goes well, a bond joint is created between the closed-out liner and the structural jacket. Pressure bags have not been 100% reliable since they can burst or leak, and it is very difficult to fabricate and maintain the correct geometry of a thin conformable pressure bag that will match the complex geometry of the combustion chamber liner and still contain the pressure required at bonding temperature.
SUMMARY OF THE INVENTION
The invention utilizes three basic components to form a combustion chamber for high-performance rocket engines: (1) a structural jacket, (2) a single-piece coolant liner, and (3) a plurality of throat support sections. The combustion chamber fabrication is described in the following steps. A liner is machined which has coolant channels formed in the outer surface. Throat support sections are fabricated and assembled around the indentation created by the venturi shape of the combustion chamber liner. The throat supports and the liner are then slid into the structural jacket. A welded or brazed seal joint between the liner and the structural jacket is made at the both forward and the aft end of the chamber. Any access ports to the coolant manifold system are closed off for the bond cycle. The coolant passages and voids between the throat support sections and the structural jacket are thus sealed off from the outside environment. The entire assembly is then placed into a furnace. The furnace is pressured and then brought up to bonding temperature. To aid in the bonding process, a vacuum may be drawn on the coolant passages and the void in the throat support area. At temperature, with the pressure applied to the entire outer surface of the jacket as well as the liner, the liner is forced to conform to the structural jacket, putting the liner into intimate contact with the jacket. At pressure and temperature, with intimate contact between the two parts, a bond joint is created between the liner and the structural jacket. Bond joints are also formed between the liner and the throat support sections, between the throat support sections themselves, and between the throat supports and the structural jacket. All of the bonding is done in one step in the pressurized furnace without requiring special tooling to force the parts into intimate contact. This method of fabrication closes out the coolant liner channels without having to utilize complicated wax filling, silver burnishing, electroplating, and machining process steps which have caused considerable problems in the past. Once the bonding is complete, the seal joint at the forward and aft end of the chamber is no longer required and may be removed from the assembly. The applicants' method eliminates all welds from the finished part. The invention is an improvement over past processes because there are no welds, there is no structural plating, and the critical liner is completely fabricated from a single piece of metal thus eliminating any joints required to form coolant channels. Further, there are no joints to be sealed longitudinally or anywhere else in the hot gas wall of the liner. The invention uses an integral liner that was machined from a single piece, which forms a barrier to isolate the hot gas from the structural jacket and preclude the coolant from leaking out into the hot gas causing a lack of coolant for the structural jacket.
One of the benefits of this fabrication method is the ability to maintain intimate contact between the liner and jacket without complicated and expensive pressure bags and structural backup tooling. Pressure bags are prone to leaks and require skilled labor to fabricate. In order for the pressure bags to withstand the high bonding loads at the high temperatures required for bonding, complicated, heavy, and expensive structural backup tooling must be used. The proposed method utilizes the liner as its own pressure bag and conforms perfectly to the outer structural jacket without any additional tooling. This represents a major simplification of the bonding process and also ensures a perfect fit between the liner and the jacket resulting in a perfect bond joint.
OBJECTS OF THE INVENTION
An object of the invention is to have a one-piece liner which is void of any joints or other material imperfections that can cause potential failure of the entire combustion chamber assembly.
Another object of the invention is to have a single bonding process which eliminates numerous weld joints and numerous structural plating processes.
It is an object of the invention to have a simple assembly process of inserting the liner into the structural jacket manifold and bonding them with a one step process.
It is a further object of the invention to make a combustion chamber by utilizing a one-piece liner fabricated from multiple pieces.
It is a further object of the invention to make a combustion chamber by utilizing a a one piece jacket manifold structure fabricated from multiple pieces.
It is a further object to utilize the one piece liner and one piece manifold jacket structure to act as pressure bags for applying force during the bonding process.
It is still another object of the invention to increase the heat transfer capability of the liner allowing the chamber to be used at higher pressures and higher temperatures and to have a longer life.
Another object of the invention is to provide ease of access to the back side of the liner which allows easy machining of the coolant passages prior to bond assembly.
Another object of the invention is to reduce the overall fabrication time, reduce the cost, and increase the quality of combustion chamber assembly.
Other objects, advantages, and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an overall expanded view of the thrust chamber assembly showing the three major components prior to assembly.
FIG. 2 is a cross section of the thrust chamber assembly.
FIG. 3 shows the assembly steps of the combustion chamber.
FIG. 4 is a cross section of the aft portion of the thrust chamber as taken from area 2--2 on FIG. 2.
FIG. 5 is a section near the forward end of the throat support of the thrust chamber as taken from area 4--4 on FIG. 2.
FIG. 6 is a cross section taken on line 8--8 of FIG. 4 through the coolant liner and structural jacket.
FIG. 7 is a cross section through the throat plane of the combustion chamber taken on line 12--12 of FIG. 2.
FIG. 8 shows an alternate geometry for a coolant liner shape.
FIG. 9 shows second alternate geometry for a coolant liner shape.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows coolant liner 3 in which coolant channels 19 are formed. These coolant channels 19 are machined from the outside and are not closed out prior to assembly. The closeout of liner 3 is formed by bonding it to the structural jacket 1 and the throat supports sections 5. The overall assembly process is depicted by the arrows. It shows that the throat support sections 5 are assembled around the indentation forming the throat 41 in the coolant liner 3. Then, the assembled coolant liner 3 and throat support sections 5 are slid into the structural jacket 1. The structural jacket 1, contains the inlet manifold 7, the outlet manifold 9 and a cylindrical portion 11.
FIG. 2 shows the overall assembly of the combustion chamber 10 in cross section. The function of the combustion chamber itself is to contain a combustion process. The combustion process creates high pressure and temperature gases. The hot gases accelerate to sonic velocity through the throat 41 and then continue to accelerate supersonically downstream of the throat to create thrust. The structural jacket 1 restrains the pressure, however, the heat generated by the combustion process would melt the structural jacket without a cooling system. Therefore, the coolant liner 3 is required to keep the structural jacket cool and within its structural margins. Coolant enters the combustion chamber through the inlet manifold 7. It then travels through the coolant inlet feed passages 13 and flows into the coolant channels 19 in the coolant liner 3. The coolant passes through coolant liner 3 at high velocity which cools the hot gas wall 17 (FIG. 4) and isolates the heat of the combustion process from the structural jacket 1 keeping it cool. The coolant then exits through the outlet feed passages 15 and exit manifold 9. The throat support 5 forms the venturi shaped portion of the throat 41 of the combustion chamber.
FIG. 2 reveals the seal joints 31 and 33, which are used during the bonding process. Once the unit is completely bonded, the excess seal joint material 35 and 37 may be removed from the overall combustion chamber as will be discussed further below.
FIG. 3 shows the assembly process for the combustion chamber. The main components, the structural jacket 1, the coolant liner 3, and the throat support sections 5 are fabricated by conventional means. Note that there are three parallel paths of fabrication for the three major components of the chamber. The outer structural jacket 1 is fabricated (FIG. 3A) simultaneously with the coolant liner 3 (FIG. 3B) and the throat support sections 5 (FIG. 3C). This reduces the overall fabrication time considerably, as compared to a series fabrication process.
The structural jacket 1 may be fabricated utilizing a casting process to form the outer structural shell and the inlet and outlet manifolding details. By utilizing a one-piece casting, this complex structure can be created at a low cost without any welds. In an alternate embodiment the one piece jacket manifold structure can be fabricated from a plurality of sections before assembly with the liner.
The coolant liner 3 can be fabricated from a single piece of suitable alloy with the coolant channels 19 formed on the outside surface with easy access. In an alternate embodiment the one piece liner can also be fabricated from a plurality of sections before assembly with the jacket.
The throat support sections 5 may also be fabricated utilizing a casting process to create a low-cost part free of weld joints.
The three major components are then assembled. In preparation for the final bonding process, the bond surface of the detail parts are coated with alloys that will form bond joints at temperature. In addition, thin sheets of braze alloy may also be applied to any of the surfaces to aid in the bonding process. For example, gold may be plated on a copper alloy liner 3 and nickel plated on a stainless steel structural jacket 1 and throat support 5. At elevated temperatures (approximately 1700° F.), the combination of nickel, copper, and gold will form an alloy that will bond all of the components together.
The throat support 5 is assembled around the coolant liner 3 as shown in FIG. 3E. For ease of assembly, the throat supports may be bolted 39 together as shown in FIG. 7. Then the coolant liner 3 along with the throat support sections 5 is installed in the structural jacket 1, as shown in FIG. 3F. To facilitate assembly, the structural jacket 1 may be heated and the coolant liner 3 and throat support sections 5 cooled to provide additional clearance between the parts during assembly.
Once the liner 3 and throat support 5 assembly is in place within the structural jacket 3G, the seal joints 31 and 33 (in FIG. 2) are made. The inlet and outlet manifolds are capped off for the bonding process. The internal voids created by the coolant passages, inlet and outlet manifolds, and between the throat support and the structural jacket are evacuated by a vacuum pump.
The entire assembly is then placed into a brazing furnace which is pressurized and brought up to bonding temperature. With the vacuum between the liner and the jacket and the external pressure on the outside of the jacket and liner, the parts are forced into intimate contact with each other. This intimate contact at temperature results in a flawless bond joint of the liner 3 to the structural jacket 1, the liner 3 to the throat supports 5, the throat supports 5 to the structural jacket 1, and the throat supports 5 to each other. Thus, the bond joint is completed for all the components in one bonding process. The entire structure is then cooled down. Once it's cooled down, the pressure is removed from the furnace. The bond is complete at this point. If needed, any excess material which was in the area of the seal joint 35, 37 can then be removed at this time.
The bonding process itself can take several different forms. The simplest of which is where the materials of the coolant liner 3 and the structural jacket 1 are held into intimate contact at temperature and pressure and form a diffusion bond. Another method utilizes materials that are plated onto the individual pieces prior to assembly and bonding. As an example, nickel plating can be applied to the structural jacket and gold plating applied to the coolant liner. These can be very thin amounts, in a range of 0.0005 inch or less. This combination of materials (nickel, gold, and the copper alloy liner), when brought up to temperature during the bonding process, form a liquidous metal or eutectic, which forms a liquid diffusion bond. The materials that are used for this type of bond joint are typically nickel and gold. However, other materials may also be plated, such as silver, depending on the materials used for the liner and the structural jacket. In another embodiment, braze alloy foil can be added between the gold and nickel plated pieces prior to assembly and prior to putting them into the bond furnace. The addition of the braze foil allows for a wider range of bonding process parameters. The added feature of using a braze alloy foil is that it flows and results in a more robust bond process.
FIG. 4 is a closeup view of 2--2 from FIG. 3. It shows the details of the aft end of the combustion chamber 10 featuring the seal joint 31 and the excess material from the seal joint 35, which may be removed following the bond process. The inlet manifold 7 is where the coolant enters the combustor assembly. The coolant then passes through the coolant inlet feed passages 13 and enters into the coolant channels 19. The high-velocity coolant provides a convective heat transfer mechanism to cool the hot gas wall 17 on coolant liner 3, therefore keeping the structural jacket 1 basically isolated from the hot combustion process.
Several joints are made during the single bond process: joint 23, between the coolant liner 3 and the structural jacket 1; joint 27, between the structural jacket 1 and the throat supports 5; and joint 25, between the coolant liner 3 and the throat supports 5.
FIG. 5 shows detail of view 4--4 of FIG. 2 featuring the forward end of the throat supports 5, the structural jacket 1, and coolant liner 3. The coolant liner 3 has bond joints 25 and 23 between the throat support 5 and structural jacket 1, respectively. Also shown is bond joint 27 between the throat support 5 and the outer structural jacket 1. All of the bond joints are completed during the same single-bond cycle previously discussed.
FIG. 6 shows a cross section through the coolant liner 3 and structural jacket 1 along line 8--8 of FIG. 4. It shows the detail of the coolant liner coolant channels 19 and the bond joint 23. The heat from the combustion process must be conducted through the hot gas wall 17 to the coolant and transferred away to keep the outer structural jacket 1 at a safe temperature below its structural limit. The coolant channels 19 are formed by the slots in the coolant liner 3 and the closeout formed by the structural jacket 1. The lands 21 in between the coolant channels 19 are integral with the hot gas wall 17. Since there is no joint between the hot gas wall 17 and the coolant in channels 19, the maximum heat transfer (fin effect) can take place providing the lowest temperature, the highest performance, and longest life chamber possible.
FIG. 7 is a section view along line 12--12 of FIG. 2 taken through the throat 41 of the combustion chamber assembly showing the coolant liner 3, the throat support sections 5 surrounding the liner 3 and the outer structural jacket 1. The pressure created by the combustion process is carried a cross the coolant liner 3 through the throat supports sections 5 to the outer structural jacket 1 by ribs 6 on the throat support sections. The bolts 39 are utilized to hold the throat support sections 5 around the liner 3 during the assembly prior to bonding. There is a bond joint 25 between the coolant liner 3 and the throat supports sections 5, a bond joint between the throat support sections themselves shown by 29, and a bond joint 27 between the throat support sections 5 and the outer structural jacket 1. All of the bond joints are created in one pressure bond process.
FIGS. 8 and 9 show coolant liners 3 having alternate shapes. The same methods of making a combustion chamber can be used with these alternate shaped liners.
In another embodiment of the invention a liner which has been closed out by some method can also be slid into the structural jacket and bonded thereto as described herein.
Both the one piece liner and the one piece jacket manifold structure can be fabricated from several parts to form the one piece liner or one piece jacket manifold structure. The one piece liner is then inserted into the one piece manifold jacket structure and bonded as described herein.
Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.
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A method of fabricating a rocket engine combustion chamber comprising assembling a liner having cooling channels, a plurality of throat support sections, and a structural jacket having inlet and outlet manifolds. Then heating the assembly in a pressurized furnace to bond the assembled parts to each other.
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This application claims benefit of Serial No. 2009901314, filed 26 Mar. 2009 in Australia and which application is incorporated herein by reference. To the extent appropriate, a claim of priority is made to the above disclosed application.
FIELD OF THE PRESENT INVENTION
The present invention relates to a ginning rib, an insert for a gin rib, a gin stand with a saw for processing cotton fibre and a method of ginning cotton fibre.
BACKGROUND OF THE PRESENT INVENTION
The present invention is applicable to modern saw-gins which are highly automated and productive systems that incorporate many processing stages besides the removal of fibre from seed-cotton.
For instance, typical operation of a modern saw-gin involves opening a module of seed-cotton weighing between 10 and 20 tonnes by a bank of beaters; the seed-cotton is then transported by air through a drying tower that dries the seed-cotton to a moisture level that ensures efficient trash removal. The seed-cotton may be pre-cleaned to remove sticks, stones and unopened bolls before proceeding to a gin stand. At the gin stand, lint is separated from the seed and transported by air to one or two lint cleaners for further cleaning. Following lint cleaning the lint is transported to the battery condenser and the bale press for pressing into a bale.
The roll box of a gin stand is where the actual ginning process, i.e. the separation of cotton fibre (lint) and seed, takes place. The ginning action is caused by multiple circular saws set on a shaft rotating between gin ribs, which are located approximately 1 mm from the saws. The teeth of the saw rake a seed-roll, which is formed in the roll box where in-coming seed-cotton is accumulated. The teeth of the saws pick and hold the fibre on seed-cotton and pass it between the gin ribs at a ginning or gin point or working zone which is substantially adjacent to the saw teeth. The gin point is a zone defined between the leading edge of the saw teeth and the gin rib. At this point the saw teeth pull the lint from the seed, which is too large to pass through the gap between the gin rib and saw, thereby separating the cotton fibre from the seed.
The ginning rib and in particular, the outer face of the ginning rib at the gin point or working zone, which is essentially a planar outer face, is subjected to significant wear and tear. In order to minimize the frequency at which the ginning ribs need replacing, sacrificial inserts or wear plates may be added to the ginning rib at the ginning zone. Like traditional one piece ginning ribs, the inserts also have a planar outer face.
SUMMARY OF THE PRESENT INVENTION
The present invention has arisen through the realisation that production rates of cotton gins are restricted by denuded or fuzzy seed becoming wedged between the ginning rib and rotating saws that prevents other seed-cotton from accessing the ginning point or zone. This wedge effect can also cause damage to the seed and fibre that can result in an overall reduction in the quality of the fibre produced.
It is an object of the present invention to provide an improved ginning rib, an insert for a ginning rib, an improved gin stand, and a method for ginning cotton fibre that can alleviate these issues.
The present invention also relates to an insert having a body that may be fixedly or removeably mounted to a ginning rib at a high wear working zone on the ginning rib, the insert or the body of the insert including:
i) side edges that extend along at least part of the length of the body; and ii) an outer face that has one or more than one guiding surfaces that extend above or below the outer face and are configured to extend in a direction inwardly of the side edges of the working zone, such that when in use, particles such as fuzzy seed or debris can be guided away from the side edges of the insert toward a central axis of the outer face.
In an embodiment, whereby when the insert is mounted to the ginning rib which is itself operatively mounted to a ginning apparatus, the outer face of the insert has a leading portion and a trailing portion relative to a direction of rotation of saws of a ginning apparatus, and the outer face of the insert has a wall section disposed between the leading portion and trailing portion so that the particles moving in a direction from the leading portion toward the trailing portion can contact the wall section and be guided away from the side edges.
Throughout this specification it will be appreciated that the term “working zone” embraces a region of the ginning rib or an insert of the ginning rib that is subject to high wear and is located near, adjacent to, or overlaps with the teeth of rotating saws. In other words, the working zone includes or overlaps with a ginning point or ginning zone that is defined between the ginning rib and the rotating saws.
Throughout this specification the term “seed-cotton” has been used to mean a seed still having the cotton lint attached and seeds that are yet to be processed in a ginning process i.e., substantially all lint remains. The terms “cotton seed” or “fuzzy seed” embrace seeds that have undergone a ginning process in which a portion, a substantially portion, or close to all of the cotton lint has been removed.
The present invention relates to a ginning rib for use in a gin stand having rotating saws, cotton lint being separated from seed-cotton over a ginning zone, or at a ginning point defined between the ginning rib and the saws, the ginning rib including:
i) a elongate body that can be operatively mounted to the gin stand between adjacent rotating saws of a gin stand; and ii) a working zone that has an outer face, side edges, and one or more than one guiding surfaces that extend above or below the outer face, the guiding surfaces are configured to extend in a direction inwardly of the side edges of the working zone, and when the ginning rib is in use, the guiding surface(s) can guide particles such as seed-cotton or fuzzy seed in a direction away from the side edges toward a central region or axis of the ginning rib.
In an embodiment, when the ginning rib is in use the working zone of the ginning rib has a leading portion and a trailing portion relative to the direction of rotation saw, and wherein the guiding surface is disposed between the leading and trailing portions and has a different level to a level of the leading portion such that the particles moving from the leading portion toward the trailing portion can contact the guiding surface and be guided away from the side edges of the working zone.
The present invention also relates to a ginning rib for use in a gin stand having rotating saws, the ginning rib including:
i) an elongate body that can be operatively mounted to a gin stand between adjacent rotatable saws of a gin stand; and ii) a working zone on the body at a high wear region of the ginning rib, the working zone having an outer face and side edges, and when the body is fastened in an operative position to the gin stand, the working zone has a leading portion and a trailing portion relative to the direction of rotation of the saw, and wherein the outer face of the working zone has one or more than one guiding surfaces that extend above or below the outer face and are configured to extend in a direction inwardly of, or inwardly from, the side edges of the working zone so that particles, such as fuzzy seed or debris moving from the leading portion in a direction toward the trailing portion can be guided away from the side edges toward a central axis or region of the working zone by the guiding surface.
The working zone may be cast from the same or different material to the material of the elongate body.
The present invention also relates to an insert having a body that may be fixedly or removably mounted to a ginning rib at a high wear working zone on the ginning rib, the insert including:
i) side edges that extend along at least part of the length of the elongate body; and ii) an outer face which when the insert is fastened to the ginning rib has a leading portion and a trailing portion as viewed from the direction of rotation of a saw, and wherein the outer face also has one or more guiding surface that is disposed between the leading portion and the trailing portion, and the guiding surface extend above or below the outer face and are configured to extend in a direction inwardly of, or inwardly from, the side edges of the working zone such that particles such as fuzzy seed or debris, moving in direction from the leading portion toward the trailing portion are guided away from the side edges toward to central region or axis of the insert by the guiding surface.
In an embodiment, the guiding surfaces include a wall section that protrudes above and/or are recessed below the outer face. Suitably, the wall section defines a recess in the form of a groove or grooves or defines a raised ridge or ridges.
In an alternative embodiment, the guiding surfaces may be in the form a depression spaced from the side edges. The depression may be symmetric or asymmetric about a central axis but is in any event recessed compared to the side edges.
In an embodiment, it is possible that the insert may be cast from different material to the main body of the ginning rib, yet integrally connected thereto.
In an alternative embodiment, the insert may be removably attached to the ginning rib, thereby enabling the insert to be replaced with a fresh insert as required. Suitably, the insert includes one or more than one attachment element or formation associated with the insert for fastening the insert to the ginning rib. The removable insert may be made of any material including metals, plastics, ceramics that are different or the same as the material of the ginning rib.
In the situation in which the working zone is integrally formed with the ginning rib, the outermost planar surface is continuous with regions of the ginning rib adjacent to the working zone. In the alternative situation in which the working zone is formed by a replaceable insert, the leading portion and/or trailing portion of the insert may be continuous with adjacent sections of the ginning rib when fitted thereto. Alternatively, either one of both of the leading and trailing portions may be discontinuous with adjacent sections of the ginning rib.
In an embodiment, the wall section protrudes to a varying height, or is recessed to a varying depth relative to the outer face of the working zone.
In an embodiment, the guiding formation, wall section or groove may have a varying or non-uniform width. For example, the width may have a maximum width of equal to, or less than 10 mm.
In an embodiment, the wall section of the guiding surface is in the form of a V-shape in which the apex of the V-shape points toward the trailing portion. Suitably, the diverging legs of the V-shape extend to the side edges.
In an embodiment, the wall section of the guiding surface has a level that is different to the level of a leading portion.
In an embodiment, the wall section extends above the surface of the leading portion and/or the trailing portion.
In an embodiment, the wall section extends below the surface of the leading portion and/or the trailing portion.
In an embodiment, the difference in levels between the wall section and the remainder of the outer face reduces such that the wall section is substantially planar with the outer face. For example, in the situation in which the wall section has a V-shape, the depth of the wall section may effectively diminish at the apex.
In an embodiment, the wall section is formed by a groove or channel that extends below the leading portion. The groove or channel may have a substantially constant depth or uniform depth. Alternatively, the groove or channel may have a varying or non-uniform depth. For example, the groove or channel may reduce in depth in a direction toward the central zone or axis of the working zone.
In another example, the groove or channel reduces in depth from the side edges to a central zone or axis.
In an embodiment, the depth of the groove or channel has a depth that is equal to, or less than 10 mm, and suitably less than 5 mm.
In an embodiment, the groove or channel has at least one of: a flat bottom wall, a curved bottom wall, or pointed bottom defined by two walls converging.
In an embodiment, the leading portion is an essentially planar surface.
In an embodiment, the trailing portion is also essentially planar.
In an embodiment, the leading portion and trailing portion may be substantially co-planar. In an alternative embodiment, the leading portion and trailing portion may be substantially non-planar.
It is within the scope of the present invention that the wall section may include one or more than one of the grooves, channels or wall sections that protrudes above or below the leading or trailing portions.
The guiding surface may include any means for guiding the particles such as frictional means including low profile barbs or teeth that resist movement of particles toward the side edges, but allow movement of the particles away from the side edges toward the centre of the ginning zone.
The present invention also relates to a gin stand including:
i) a frame assembly; ii) a plurality of saws that are rotatably mounted to the frame assembly about a common axis, wherein the saws are spaced from one another in adjacent relationship; and iii) a plurality of ginning ribs of which at least one includes, and suitably all of each include, a working zone having any one or combination of the features of the working zones described above.
The present invention also relates to a gin stand including:
i) a frame assembly; ii) a plurality of saws that are rotatably mounted to the frame assembly about a common axis, wherein the saws are spaced from one another in adjacent relationship; and iii) a plurality of ginning ribs of which at least one includes, and suitably all of each include an insert having any one or combination of the features of the inserts described above.
The present invention also relates to a method of ginning seed-cotton in a ginning apparatus including a frame assembly, a plurality of saws that are rotatably mounted to the frame assembly about a common axis and are spaced from one another in adjacent relationship, and a plurality of ginning ribs of which one is located between some or all of the saws and in which the ginning ribs have a working zone at a high wear region of the ginning rib, the working zone having an outer face and side edges, the outer face of the working zone has one or more than one guiding surfaces that extend above or below the outer face and are configured to extend in a direction inwardly of, or inwardly from, the side edges, and wherein the method includes:
a) feeding seed-cotton onto the saws of the cotton gin; b) rotating the saws so that cotton lint of the seed-cotton is caught by the saw, and the seed-cotton is pulled toward the ginning rib for removing cotton lint from the seed-cotton; c) allowing the seed-cotton to engage the guiding surfaces of the ginning ribs which urge the seed-cotton away from the side edges of the ginning ribs; and d) collecting the cotton lint separate.
In an embodiment, the seed-cotton engages the guiding surfaces and moves in a direction away from the side edges of the working zone while the cotton lint is being removed from the seed-cotton during rotation of the saws.
In an embodiment, the working zone has a leading portion and a trailing portion relative to the direction of rotation of the saw, and the seed-cotton moves in a direction away from the side edges of the working zone while moving in a direction from the leading portion to the trailing portion.
In an embodiment, the working zone may be a zone that is integrally formed with the rib or, alternatively, the working zone may form part of a removable insert.
The method of the present invention may be applied to any cotton fibre type including long and short Upland ( Gossypium hirsutum ) cottons which account for approximately 90% of the total cotton grown globally.
When the seed-cotton is Upland seed-cotton, an embodiment of the method of the invention includes removing more cotton lint from the seed-cotton so that less residual lint remains on the fuzzy seed after one pass through the ginning apparatus. Typically, we have found that the method of the invention can remove 0.5% more cotton lint by weight compared to conventional methods in which standard ginning ribs or rib inserts are used. The term “residual lint” as used herein is a mass ratio (usually as a percentage) of the lint remaining on the denuded seeded cotton (fuzzy seed) to the total weight of the denuded seeded cotton.
We have found that the residual lint percentage on the fuzzy seed using the invention is at least 0.5% by weight less than the residual lint percentage using a conventional ginning rib or insert (i.e., without a guiding formation), and suitably at least 1.0 to 1.5% by weight less. In a preferred embodiment, the residual lint percentage is decreased by 0.5% to 1.5%, or 0.5% to 2.0%, relative to using a conventional ginning rib or insert.
In an embodiment, less than 10.9 wt %, and even more suitably less than 10.7 wt %, and yet even more suitably approximately 10.5 wt % residual lint remains on the fuzzy seed. In a preferred embodiment, the residual lint percentage is in the range 10.5% to 10.9%.
We have found that the mean long length of the fibre removed from the seed-cotton is typically longer, by an amount of 0.02 inches (0.51 mm), than the mean long length of fibre using a conventional ginning rib or insert (i.e., without a guiding formation). In a preferred embodiment, the mean long fibre length is increased by 0.01 inches to 0.04 inches relative to using a conventional ginning rib or insert. It will be understood that the term “mean long length” of fibre is an average fibre length of the upper half or longest half of the fibres in a sample.
We have found that mean long fibre lengths of the present invention are at least 0.5% greater that the mean long fibre length produced using a conventional ginning rib or insert, and suitably at least 1.0 to 2.0% greater. In a preferred embodiment, the mean long fibre length is increased by 0.5% to 1.5%, or 0.5% to 2.0%, relative to using a conventional ginning rib or insert.
In an embodiment, the mean long fibre length may be greater than 1.07 inches (2.718 cm). Even more suitably, the mean fibre length is greater than 1.075 inches (2.731 cm). In a preferred embodiment, the mean long fibre length is 1.07 inches to 1.10 inches.
We have found, the length of fibre removed from the seed-cotton has a lower mean short fibre index the mean long length of fibre using a conventional ginning rib or insert (i.e., without a guiding formation). It will be understood that the term “short fibre index” of fibre is the average percent by weight of fibres in a sample with a fibre length less than ½ inches (12.7 mm).
We have found that the mean short fibre index of the present invention is at least 0.5% by weight less that the mean short fibre index produced using a conventional ginning rib or insert, and suitably at least 1.5 to 2.0% by weight less. In a preferred embodiment, the mean short fibre index is decreased by 0.5% to 2.0% relative to using a conventional ginning rib or insert.
Each of these changes was unexpected and could not have been predicted prior to testing the inserts. Each of the changes is highly significant in economic terms since each 0.1% change represents millions of dollars per year to the cotton industry. Each of the improvements described herein is understood to be relative to ginning of the same variety of cotton, ginned under the same conditions, but using a conventional ginning rib or insert.
The present invention also relates to a method of ginning seed-cotton in a ginning apparatus including a frame assembly, a plurality of saws that are rotatably mounted to the frame assembly about a common axis and are spaced from one another in adjacent relationship, and a plurality of ginning ribs of which one is located between some or all of the saws and in which the ginning ribs have a working zone at a high wear region of the ginning rib, the working zone having an outer face and side edges, the method including:
a) providing the outer face of the working zone with at least one guiding surface that extends above or below the outer face and is configured to extend in a direction inwardly of, or inwardly from, the side edges; b) feeding seed-cotton onto the saws of the cotton gin; c) rotating the saws so that cotton lint of the seed-cotton is caught by the saw, and the seed-cotton is pulled toward the ginning rib for removing cotton lint from the seed-cotton; and d) allowing the seed-cotton to engage the guiding surfaces of the ginning ribs which urge the seed-cotton away from the side edges of the ginning ribs.
It is within the scope of the present invention that the gap between the saws and ginning ribs may be any size. For instance, the gap may be up to 2 or 3 mm, or as little as 0.15 mm, and suitably in the range of 0.25 to 2.25 mm.
The present invention also relates to cotton lint produced by the method described herein.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will now be described with reference to the accompanying drawings, of which:
FIG. 1 is a schematic illustration of a conventional prior art gin stand;
FIG. 2 is a perspective view of a partially assembled saw-gin roller box comprising a plurality of the saws and ginning ribs;
FIG. 3 is a schematic illustration showing a side view of a single ginning saw and ginning rib associated with the saw;
FIG. 4 is a photograph showing a perspective view of an insert for a ginning rib according to a preferred embodiment of the present invention;
FIG. 5 is a photograph of the insert shown in FIG. 4 in which the insert has been fitted to a ginning rib and is shown in relation to the saw of a saw-gin roller box and a fuzzy seed located on the insert;
FIGS. 6 and 7 are graphs showing results of a trial in which the preferred embodiment of the rib insert shown in FIGS. 4 and 5 (i.e. Directional Rib Insert DRI), and a conventional rib insert with no outer profile (i.e. Control) were tested, the graph shows the amount of residual cotton lint on the seed;
FIG. 8 is a graph showing results of the same trial of the preferred embodiment and Control, the graph shows Fibre Length at 2 production rates;
FIG. 9 is a graph showing results of the same trial of the preferred embodiment and the Control in terms of a Short Fibre Index at 2 production rates;
FIG. 10 is a block diagram showing steps of a method for ginning seed-cotton according to an embodiment of the invention;
FIGS. 11 and 12 are photographs showing perspective views of an upper face of two inserts for a ginning rib according to alternative embodiments;
FIGS. 13 and 15 are schematic illustrations of an upper face of two inserts for a ginning rib according to further alternative embodiments;
FIGS. 14 and 16 are cross-sectional views of the inserts along an axis line 46 shown in FIGS. 13 and 15 respectively; and
FIGS. 17 and 18 are perspective views of a working zone of a ginning rib have guiding formations according to alternative embodiments.
DETAILED DESCRIPTION
FIG. 1 is a side view of a gin stand 10 comprising a rotating saw roller 11 having a series of equally spaced apart saws 12 that are rotatably driven about a common axis 13 , a set of ginning ribs 14 that are fixed to a frame assembly 15 of the gin stand 10 at one attachment point 16 and a doffing roller 17 that removes lint from the saw 11 . The ginning ribs 14 extend from the attachment point 16 above the saw 11 and curve downwardly between the saw blades 12 . In the case of the embodiment shown in FIG. 1 , the lower end of the ginning rib 14 is not fixed to a second attachment point.
FIG. 2 illustrates a perspective view of a roller box 19 of gin stand in which the ginning ribs 14 are fixed to the frame assembly 15 at upper and lower attachment points 16 and 18 respectively and the direction of rotation of the saws blades 12 . FIG. 2 clearly shows how the set of the ginning ribs 14 are arranged in a series between the saw blades 12 . In operation, separation of cotton lint from seed-cotton takes place in the roller box 19 of the gin stand 10 . Cotton fibre on the seed-cotton is caught by the teeth of the saws 12 and pulled toward the ginning ribs 14 . At the upper end of the ginning ribs 14 , the teeth of the saws 12 pass between adjacent ginning ribs 14 on either side. The ginning ribs 14 and saws 12 are separated by a gap and cotton fibre is pulled from the seed-cotton, by the teeth of the saw. The gap between the ginning rib 14 or the side edge of the insert set in the ginning rib and the saws 12 in this region is known as the ginning point or ginning zone. The seed-free cotton lint passes through the ginning point or zone and is removed from the saw teeth by the doffing roller 17 . Seed free of cotton lint (fuzzy seed), or substantially free of the lint can fall downward between the ginning ribs 14 and the saws 12 and eventually onto a conveyor or lower chamber 20 (as shown in FIG. 1 ) and removed from the lint stand 10 . Seed free of lint (fuzzy seed) can also be pushed into the centre of the seed roll and be expelled via a seed tube or auger from the seed roll. Partially de-linted seeds or seeds having long fibres thereon are generally pushed upward along the ginning rib 14 to undergo the ginning process yet again.
The gap between the gin ribs and the saws may be any suitable gap, for example, and without limitation, a gap in the range of 0.25 mm to 2.5 mm may be employed.
FIG. 3 is a schematic illustration of a side view of a saw 12 and a ginning rib 14 . The arrows identified by reference numeral 30 show the general movement of seed-cotton having lint. The arrow 31 identifies the ginning point or zone at which the seed-cotton has the strands of fibre removed from the seed.
We have found that the production capacity of the ginning stand is limited by fuzzy seed becoming wedged between the ginning rib and the saw at the ginning zone. The wedging effect prevents access for other seed-cotton to the ginning zone. Furthermore, denial of access of seed-cotton can also result in damage of seeds which can cause broken seeds to travel between the saws and into lint cleaning stages downstream of the ginning stand 10 .
To reduce the incidence of blockage of the ginning zone and, in turn, reduce the incidence of damage to fuzzy seeds and breakage of the cotton, we have devised an improved ginning rib or insert for a ginning rib.
The improvement comprises the ginning rib or insert for a ginning rib having a contoured outer face. FIG. 4 illustrates an example of an insert having a main body 40 and an attachment formation in form of a fastening stem or lug 41 that extends below the main body 40 . A top surface of the fastening stem is seen flush with the outer face of the insert. When in use, a fastening stem is received by a opening in the ginning rib and is oriented such that the outer face of the insert is located at in an orientation that is non-perpendicular to a radial line from the axis of rotation of the saw, see FIG. 3 . The orientation of the insert relative to the direction of rotation of the saw defines a leading portion 42 including a leading edge and a trailing portion 43 including a trailing edge that are separated by a guiding formation 44 .
In the case of the preferred embodiment shown in FIG. 4 , the leading and trailing portions 42 , 43 respectively have flat planar surfaces that are substantially co-planar. However, this need not necessarily be the case. For instance the leading portion 42 may be recessed at a level below the surface of the trailing portion 43 . When the insert is located in an in use or operative position on a ginning rib, the surface of the leading portion 42 is essentially continuous with the outer surface of the ginning rib 14 .
The guiding formation 44 shown in FIG. 4 has a V-shape with an apex 45 that terminates at the top of the insert which is generally in line with the central longitudinal axis 46 of the insert. Moreover, the V-shape may be said to be locate intermediate or between the leading and trailing portions 42 and 43 .
The V-shape is in the form of a groove or channel that is ground out of what is otherwise an essentially planar outer face between opposite side edges 47 . The V-shape may have a flattened, rounded or sharpened bottom line that extends part way, or along the entire length of the V-shape. In the case of the embodiment shown in FIG. 4 , the bottom is defined by two converging wall sections 48 a and 48 b . In addition, the depth of the V-shape reduces or tapers from side edges 47 of the insert to the apex 45 at the top of the insert. Moreover, the depth of V-shape reduces to zero or negligible at the apex 45 .
The wall sections 48 a , 48 b also define the width of the groove of the V-shape. The width also reduces or tapers from its widest point at the side edges 47 of the insert to the narrowest point of the groove at or approaching the apex 45 .
The V-shape may be symmetrical or asymmetric about the apex 45 . Similarly, the wall sections 48 a , 48 b that converge to form the base or bottom line of the groove may also be symmetric or asymmetric about the bottom line. In the case of the embodiment shown in FIG. 4 , the wall sections 48 a , 48 b are symmetrical, however, the wall sections 48 a adjacent to the leading portion 42 may appear to have less gradient than the opposed wall section 48 b on account, merely the wall sections 48 b extends further than wall section 48 a.
FIG. 5 is a photograph that shows the insert of FIG. 4 fitted to a ginning rib 14 and with the ginning rib 14 located in a position relative to one saw 12 . As can be seen, the trailing portion 43 of the insert is essential planar or continuous with the ginning rib 14 . The leading portion 42 would likewise be planar with the ginning rib 14 .
As can be seen, the V-shaped formation is adapted to receive a fuzzy seed 50 . In particular, when in the use, the fuzzy seed 50 moving from the leading portion 42 of the insert toward the trailing portion 43 can be received by the V-shaped formation so as to move the fuzzy seed 50 away from the side edges 47 of the insert and, in turn the ginning point or zone between the ginning rib 14 and the saw 12 . In other words, the V-shaped formation guides the fuzzy seed 50 toward the central region or axis 46 of the insert while the fuzzy seed 50 is in the ginning zone. We have found that configuring the insert in this manner reduces the incidence at which fuzzy seeds can become wedged or jammed between the ginning rib 13 and the saw 12 at the ginning zone.
In other words, material travelling along the ginning rib 14 at the ginning zone is directed away from the edges 47 of the ginning rib 14 . The benefits of this effect are numerous. For example, the present invention can: i) open up the ginning zone improving fibre transfer and reducing the natural tendency for the saw to pull the fuzzy seed down into the ginning zone which ‘wedges’ fuzzy seeds in the space between the saw and ginning point, ii) reduce the incidence of damage to cotton, iii) reduce the incidence of the fuzzy seed being broken which can result in the broken fuzzy seed passing between the ginning rib and the saw and into the lint separated from the seed, iv) enables more seed-cotton to access the ginning zone on account that fewer fuzzy seeds become wedged between the ginning rib and the saw.
FIGS. 11 to 16 illustrate examples of inserts according to alternative embodiments. The inserts have a main body 40 and an opening for an attachment formation such as a fastening stem or lug 41 (not shown in FIGS. 11 and 12 ). Like the embodiment shown in FIGS. 4 and 5 , the inserts of FIGS. 11 to 16 have a leading portion 42 and a trailing portion 43 that are defined by the direction of rotation of ginning saws.
The leading and trailing portions 42 , 43 of the alternate embodiments are substantially co-planar. However, this need not necessarily be the case. For instance the leading portion 42 may be recessed at a level below the surface of the trailing portion 43 . Although not illustrated, when the insert is located in an in use or operative position on a ginning rib, the surface of the leading portion 42 is essentially continuous with the outer surface of the ginning rib 14 .
In the case of the embodiment shown in FIG. 11 the insert has a guiding formation 44 in the form of a V-shape in the form of a groove or channel. The groove includes wall sections 48 a and 48 c that extend essentially perpendicularly downward to the trailing and leading portions 43 and 42 , and includes a bottom wall section 48 b that defines a substantially flattened bottom. The depth of the groove is substantially uniform and extends from opposite side edges of the insert to a trail edge of the trailing portion of the insert. As can be seen, the groove forms a cutout in the trailing edge of the insert that is located on the longitudinal axis 46 .
In the case of the embodiment shown in FIG. 12 , the insert has a guiding formation 44 in the form of a V-shaped groove or channel. The groove includes wall sections 48 a and 48 c that converge to a point at the bottom of the groove. The depth of the groove is substantially uniform and extends from opposite side edges of the insert to a trail edge of the trailing portion of the insert. As can be seen, the groove extends into the trailing edge of the insert to form a cutout on the longitudinal axis 46 .
In the case of the embodiment shown in FIGS. 13 and 14 , the guiding formation 44 is in the form of depression that is spaced from the side edges 47 and spaced from the trailing and leading edges of the insert. The depression is centrally located about the longitudinal axis 46 and is located between substantially equally sized trailing and leading portions 42 and 43 .
FIGS. 15 and 16 illustrate yet another alternative insert in which that guiding formation 44 is in the form of a ridge that protrudes above leading and trailing portions 42 and 43 . The ridge is in the form of a V-shape and includes wall sections 48 a and 48 b that extend upwardly of the face of the insert. The wall sections 48 a and 48 b are interconnected by a wall section 48 b that defines a flattened outer surface on the ridge. As can be seen in FIG. 15 , the width of the ridge is at a maximum at the side edges 47 of the insert and reduces to a minimum or negligible height at the axis 46 . In addition, as can be seen in FIG. 16 , the height of the ridge decreases from the side edges 47 toward the axis 46 .
FIGS. 17 and 18 illustrate a working zone portion of a ginning rib 14 according to an embodiment. The ginning rib 14 has an elongate body with side edges 47 at the working zone. The working zones define a guiding formation 44 for guiding seed-cotton away from the side edges 47 when in use. In case of the embodiment shown in FIG. 17 , the guiding formation is in the form of a V-shaped groove that extends from the side edges 47 inwardly toward a longitudinal axis 46 . The groove is defined by converging wall sections 48 a and 48 b that join at the bottom of the groove. The depth of the V-shaped groove is non-uniform and specifically, decreases in depth from the side edges 47 toward the axis 46 . When the ginning rib 14 is in use, the direction of rotation of saws (not shown) defines leading and trailing portions 42 and 43 either side if the V-shaped groove.
In case of the embodiment shown in FIG. 18 , the guiding formation 44 is in the form of a V-shaped ridge that extends from the side edges 47 inwardly toward a longitudinal axis 46 . The ridge is defined by wall sections 48 a and 48 c that protrude from the face of leading and trailing portions 42 and 43 . An outer face 48 b is a flattened outer surface that joins the wall sections 48 a and 48 c . As can be seen, the width of the ridge reduces from a maximum at the side edges 47 to a longitudinally axis 46 . Similarly, the height of the ridge also reduces from a maximum at the side edges 47 to a negligible height at the axis.
It is within the scope of the present invention that the guiding formation may be in the form of a ridge, crest or rib. For example, the ridge or crest may protrude above the leading and/or trailing portions. In another embodiment, it is also possible that the guiding formation may in the form of a triangular or diamond formation having an apex of reducing depth located toward the top of the insert. According to another embodiment, it is also possible that the guiding formation may be in the form of a depression or recess, such as an elongate depression that is displaced inwardly of the side edges of the insert.
The embodiments of the removable insert described above can be replaced with a fresh insert in the event of wear or failure of the insert. However, it will be appreciated that it is within the scope of the present invention that any guiding formation such as V-shaped formation for guiding seed-cotton or fuzzy seed away from the side edges of the ginning rib may be integrally formed with a ginning rib. In this situation, the guiding formation, and the leading and trailing portions of the ginning rib may made from the same material as the remainder of the ginning rib or, alternatively, made from material having a higher wear resistance than the remainder of the ginning rib.
It is also within the scope of the present invention that the removable insert be reversible and have guiding surfaces on opposite sides of the insert.
Method
A method according to an embodiment of the invention includes using of a rib insert or ginning rib that urges the seed-cotton away from the ginning point. With reference to FIG. 10 , the method includes feeding seed-cotton onto a series of rotating saws of a gin stand. The saws are spaced apart and separated by ginning ribs that may include an insert having a guiding formation, for example, see the inserts shown in FIGS. 4 , 5 , and 11 to 16 . Alternatively, the ginning ribs may have integrally formed guiding formations at the working zone, for example, see the ginning ribs in FIGS. 16 and 17 . Lint of the seed-cotton is caught of the teeth of the rotating saws which pulls the seed-cotton toward and onto the ginning rib. The guiding formations of the ginning ribs, or inserts fitted to the ribs, contact the seed-cotton as the seed-cotton moves under the influence of the saws. Specifically, the working zone over which seed-cotton is delinted includes a leading portion as defined by the direction of rotation of the saws. As the seed-cotton moves over the working zone from the leading portion toward the trailing portion, the guiding surfaces urge the seed-cotton away from the gap between the ginning rib and the saws. For example, the guiding formation may guide the seed-cotton toward a central zone of the ginning rib. Lint separated from the seed-cotton may then be collected by a doffing roller or other suitable device.
Finally, the method may include replacing the rib inserts as the guiding formations thereon wear, or in the situation in which the guiding formations are integrally formed with the ginning ribs, the entire ginning rib may be replaced.
Trial
A rib insert having a guiding formation as shown in FIGS. 4 and 5 , and a conventional insert without a guiding formation, have been tested and assessed. The test involved forming a ginning roll including ginning ribs having inserts with guiding formations on one half and the conventional inserts on the other half. Upland seed-cotton was feed onto the ginning roll which was operated at two separate production rates, notionally identified as 100 kw and 90 kw production rates in FIGS. 8 and 9 . Samples of cotton lint separated from the seed-cotton were collected from opposite ends of the ginning roll. The properties of the lint separated and collected from the half of the ginning roll having the rib insert with the guiding formation (shown in FIGS. 4 and 5 ) is represented by the letters DRI (direction rib insert) in FIGS. 6 to 9 , and the lint separated and collected from the half of the ginning roll having the conventional rib is the “Control” in FIGS. 6 to 9 .
Samples of the fuzzy seed i.e., the seed after processing were also collected from opposite ends of the ginning stand.
FIGS. 6 and 7 are graphical representations of guiding formations increasing the extent of separation of cotton lint and hence increasing yield compared that achieved using a conventional gin. Specifically, in the case of FIG. 6 residual lint on the fuzzy seed reduced from approximately 11.1% from the Control to approximately 10.5% using the DRI inserts. In the case of FIG. 7 , residual lint reduced from approximately 8.1% for the Control to approximately 6.6% using the DRI inserts, i.e., a reduction of approximately 1.5%.
The greatest return to growers and ginners is in the ability to facilitate removal of more cotton lint from the seed. As shown by the trial, residual lint on fuzzy seed can be reduced by approximately 1%. In the past, an increase in ginning efficiency of 1% has only been achievable by constricting roll box dimensions, for example such as reducing the distance of the gap between the seed fingers and the ginning rib. However, reducing the dimensions between the dimensions in this way has a downside of creating more fibre damage, which in turn, reduces the length of the fibre separated.
The trial conducted has shown that this is not a downside when using guiding formations. Moreover, FIG. 8 shows that the long fibre length of the sample of fibre actually increases to levels of approximately 1.078 inches and 1.075 inches for the two productions rates, whereas the fibre lengths produced for the Control (i.e., the conventional ginning rib) is approximately 1.062 inches and 1.068 inches respectively for the sample production rates and at the same spacing between the ginning ribs and the saws. Similarly, FIG. 9 shows that the short fibre index reduced to levels below 10.9 and 10.7, whereas the short fibre index for the conventional ginning rib i.e., the Control was approximately 11.04 and 10.7 at the sample production rates and at the same spacing between rib and insert.
Those skilled in the art of the present invention will appreciate that many variations and modifications may be made to the preferred embodiment without departing from the spirit and scope of the present invention.
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The present invention relates to a rib insert, a ginning rib and process for a ginning seed-cotton. The insert and ginning rib have an outer profile so that seed-cotton in contact therewith is urged away from the ginning zone formed between the ginning rib and saw. Advantages of the invention include increasing the rate of lint removal during ginning and increasing the long fiber length compared to conventional ginning.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a fresh water generating apparatus condensing a water content in an atmospheric air so as to generate a fresh water, and more particularly to a structure preferably used for generating a fresh water in a desert area having a comparatively high temperature or the like by utilizing a refrigerating cycle.
[0003] 2. Description of the Prior Art
[0004] In the desert area, it is very hard to secure a life water such as a drinking water, an agricultural water, an industrial water and the like, there is a little river and it is hard to utilize the river. Further, an underground water has been utilized, however, when the underground water is dipped too much, a sea water gets into the underground water.
[0005] Further, a seawater desalination plane has been placed in a coastal area so as to obtain the water from the sea water, however, it is impossible to completely remove a salt content in the sea water, and a small amount of salt content is left in the obtained water.
[0006] Accordingly, there has been proposed an apparatus for condensing the water content in the air so as to obtain the fresh water, whereby there has been a structure in which a plurality of fresh water generating panels having hollow inner portions are placed and a refrigerant cooled by a cooling unit is circulated within the fresh water generating panels, thereby condensing the water content in the air on the surfaces of the fresh water generating panels so as to generate the fresh water. This structure is described, for example, in JP-A-9-99201.
[0007] In the prior art mentioned above, it is hard to sufficiently cool the refrigerant flowing through the fresh water generating panels by the cooling unit, and there is a case that an outside air temperature reaches 50° C. in the desert area or the like. Accordingly, since it is impossible to make the temperature of the cooling unit sufficiently low when cooling the refrigerant by the high temperature ambient air, an efficiency of fresh water generation is reduced and it is hard to efficiently generate a lot of fresh water.
[0008] Further, in a place to which an electric power is not supplied, such as a developing area and the like, since it is impossible to generate the fresh water and the drinking water is very greatly demanded, it is desired to make the generated fresh water the drinking water.
SUMMARY OF THE INVENTION
[0009] An object of the present invention is to solve the problems in the prior art mentioned above so as to obtain a structure having an improved fresh water generating efficiency and suitable for generating a lot of water. Further, another object of the present invention is to obtain a structure in which a region for placement does not depend on a matter whether or not an electric power is supplied, it is easy to transfer due to a compact size, and an excellent property in view of a maintenance and an operability can be provided.
[0010] In this case, the present invention solves at least any one of the objects and the problems mentioned above.
[0011] In order to solve the problems mentioned above, in accordance with the present invention, there is provided a fresh water generating apparatus for condensing a water content contained in an air so as to collect by utilizing a refrigeration cycle, comprising:
[0012] a first heat exchanger having a refrigerant gas flow passage to which a compressed refrigerant gas is introduced, and blowing the air in an outer side of the refrigerant gas flow passage so as to condense the refrigerant gas;
[0013] a second heat exchanger having a refrigerant liquid flow passage to which a refrigerant liquid discharged from the first heat exchanger is introduced after a pressure thereof is reduced, and blowing the air in an outer side of the refrigerant liquid flow passage so as to cool; and
[0014] a power source for compressing the refrigerant gas and blowing the air,
[0015] wherein the second heat exchanger is placed at an upstream position within the air flow passage in which the air is blown, the first heat exchanger is placed at a downstream position, the power source introduces an ambient air containing a water content corresponding to the air from an external portion of a chamber, and the second heat exchanger condenses the water content in the ambient air so as to generate a fresh water.
[0016] In this case, the power source for compressing the refrigerant gas and blowing the air means compressing and blowing by using the power source, and it is particularly executed by driving a compressor for compressing the refrigerant gas by a power generator having a fuel tank, a fuel battery, a solar battery, a wind power generator or the like, or an air blower rotated by a direct-current motor or an alternating-current motor.
[0017] Accordingly, since the first heat exchanger is placed at a downstream position of the second heat exchanger, the water content in the ambient air is condensed by the second heat exchanger, whereby the cooled ambient air reaches the first heat exchanger. Then, since it is possible to effectively cool the compressed refrigerant gas introduced to the first heat exchanger, and it is possible to condense the refrigerant gas by the first heat exchanger without compressing the refrigerant gas to a high pressure, it is possible to generate the fresh water at a high efficiency.
[0018] Accordingly, it is possible to make the power source for compressing the refrigerant gas and blowing the air comparatively compact, and it is possible to make the structure having an easy transferring property, an excellent maintenance property and an excellent operability.
[0019] Further, in accordance with the present invention, there is provided a fresh water generating apparatus for condensing a water content contained in an air so as to collect by utilizing a refrigeration cycle, comprising:
[0020] a compressor for compressing a refrigerant gas;
[0021] a condenser for cooling the refrigerant gas compressed in the compressor so as to condense;
[0022] an expansion valve for reducing a pressure of a refrigerant liquid condensed in the condenser;
[0023] an evaporator for evaporating the refrigerant liquid the pressure of which is reduced by the expansion valve;
[0024] a blower for introducing an ambient air containing a water content from an external portion of a chamber so as to blow to the condenser and the evaporator;
[0025] a water storage tank for recovering a fresh water obtained by the water content in the ambient air blown by the blower being cooled by the evaporator and condensed; and
[0026] a power source for driving the compressor and the blower.
[0027] Accordingly, since the ambient air is blown to the condenser and the evaporator on the basis of the power source driving the compressor and the blower, and the condensed water is recovered in the water storage tank, it is possible to effectively cool the compressed refrigerant gas and it is possible to generate the fresh water at a high efficiency. Therefore, it is possible to make the power source comparatively compact and assemble together with the water storage tank in a compact manner.
[0028] Further, in the structure mentioned above, it is desirable to provide with a case receiving a fresh water generator receiving the first heat exchanger and the second heat exchanger, having a blow-off port on an upper surface thereof and having a heat insulating material being wound around an outer side thereof, and the power generator. Accordingly, by using a transporting means such as a truck or the like, it is possible to place in a plurality of farms (fields), factories or the like, or it is possible to supply the drinking water to dwellings or the like.
[0029] Further, in the structure mentioned above, it is desirable to provide with a case receiving a fresh water generator receiving the compressor, the condenser, the expansion valve, the evaporator and the blower, having a blow-off port on an upper surface thereof and having a heat insulating material being wound around an outer side thereof, the water storage tank and the power generator. Accordingly, it is possible to prevent a temperature within the structure from being increased even in a place where a temperature is increased during the day.
[0030] Further, in the structure mentioned above, it is desirable that the ambient air is introduced to the condenser and the evaporator via a dust filter.
[0031] Further, in the structure mentioned above, it is desirable to provide with a case receiving a fresh water generator receiving the compressor, the condenser, the expansion valve, the evaporator and the blower, having a blow-off port on an upper surface thereof and having a suction port to which a dust filter is mounted on a side surface, the water storage tank and the power generator.
[0032] Further, in the structure mentioned above, it is desirable that the evaporator is placed at an upstream position within the air flow passage to which the ambient air is blown, and the condenser is placed at a downstream position.
[0033] Further, in the structure mentioned above, it is desirable that a fuel tank in which a fuel is charged a power generator generating an electric power by using the fuel are provided, and the electric power generated by the power generator is utilized as the power source.
[0034] Further, in the structure mentioned above, it is desirable that the power source is a power generator generating an electric power by using the fuel stored in the fuel tank and the apparatus is provided with a case receiving a fresh water generator receiving the compressor, the condenser, the expansion valve, the evaporator and the blower, and having a heat insulating material being wound around an outer side thereof, the water storage tank, the power generator and the fuel tank.
[0035] Further, in the structure mentioned above, it is desirable to provide with a fresh water generator receiving the compressor, the condenser, the expansion valve, the evaporator and the blower and provided with a drain pan collecting the condensed water, and dip up the water collected in the drain pan by a pump so as to store in the water storage tank.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] [0036]FIG. 1 is a schematic view showing a whole of an embodiment in accordance with the present invention;
[0037] [0037]FIG. 2 is a schematic view showing a whole of another embodiment in accordance with the present invention;
[0038] [0038]FIGS. 3A, 3B and 3 C are three elevational views showing a storage (a case) in accordance with an embodiment;
[0039] [0039]FIGS. 4A, 4B and 4 C are three elevational views showing a fresh water generator in accordance with an embodiment;
[0040] [0040]FIG. 5 is a perspective view showing a receiving state of a fresh water generator in accordance with an embodiment;
[0041] [0041]FIG. 6 is a perspective view showing a transportation container in accordance with an embodiment;
[0042] [0042]FIGS. 7A, 7B and 7 C are three elevational views showing an arrangement within the container shown in FIG. 6;
[0043] [0043]FIGS. 8A, 8B and 8 C are three elevational views showing an arrangement within a container in accordance with another embodiment;
[0044] [0044]FIGS. 9A and 9B are three elevational views showing an arrangement within a container in accordance with the other embodiment; and
[0045] [0045]FIG. 10 is a block diagram showing a refrigerant cycle in accordance with an embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0046] A description will be given below of an embodiment in accordance with the present invention.
[0047] [0047]FIG. 1 shows a whole structure of a fresh water generating apparatus in which a power source 6 is additionally provided, in accordance with an embodiment. A fresh water generator 10 condensing an ambient air is constituted by a refrigerant cycle having a compressor 1 , a condenser 2 and an evaporator 4 . A refrigerant gas becoming a high temperature and a high pressure in the compressor 1 is cooled and condensed by the condenser 2 so as to become a refrigerant liquid. This refrigerant liquid is reduced in a pressure by a pressure reducing device 3 so as to expand, and becomes a refrigerant having a low temperature and a low pressure so as to be fed to the evaporator 4 . When an atmospheric air (an ambient air) containing a water content is fed within the fresh water generator 10 by a blower 5 , the atmospheric air is cooled by the refrigerant having the low temperature and the low pressure at a time of flowing through the evaporator 4 , and the water content contained in the atmospheric air is condensed.
[0048] [0048]FIG. 10 shows a refrigerant cycle of a fresh water generating apparatus in accordance with the present embodiment, and a description will be given of a detail thereof. As shown in FIG. 10, a discharge side of the compressor 1 is connected to an inlet side of the condenser 2 by a connecting piping having a silencer 82 in the middle thereof. The silencer 82 is provided for the purpose of absorbing a pulsation of the refrigerant gas compressed by the compressor 1 so as to become a high temperature and a high pressure. An outlet side of the condenser 2 is connected to a distributor 87 by a connecting piping having a strainer 83 and an expansion valve 3 in the middle thereof, and the distributor 87 is connected to an inlet side of the evaporator 3 so as to distribute the refrigerant. An outlet side of the evaporator 4 is connected to an inlet side of an accumulator 84 and an outlet side of the accumulator 84 is connected to a suction side of the compressor 1 . Further, a piping having an electromagnetic valve 85 and a capillary tube 86 is provided, one end of the piping is connected to a portion between the strainer 83 and the expansion valve 3 and another end of the piping is connected to a portion between the outlet side of the evaporator 4 and the inlet side of the accumulator 84 .
[0049] In the structure mentioned above, the refrigerant gas is compressed by the compressor 1 so as to become the refrigerant gas having a high temperature and a high pressure, and flows in the condenser 2 after passing through the silencer 82 . The ambient air cooled by the evaporator 4 is blown to a periphery of the condenser 2 by the blower 5 , and the refrigerant gas having the high temperature and the high pressure flowed in the condenser 2 exchanges heat with the ambient air around the condenser 2 so as to be cooled and condensed, thereby becoming a refrigerant liquid. The refrigerant liquid is reduced in a pressure by the expansion valve 3 after passing through the strainer 83 so as to expand, thereby becoming a refrigerant having a low temperature and a low pressure. The refrigerant flows in the evaporator 4 after being distributed by the distributor 87 . The ambient air is blown around the evaporator 4 by the blower 5 , and the refrigerant having the low temperature and the low pressure introduced to the evaporator 4 cools the ambient air around the evaporator 4 . Accordingly, the water content contained in the ambient air is condensed so as to be attached onto a surface of the evaporator 4 as a ball of water. When keeping the operation, a lot of ball of water is attached onto the surface of the evaporator 4 , and the ball of water finally grows large so as to drop down on a drain pan 9 due to a gravity. Further, the ball of water dropping down on the drain pan 9 one by one flows to one side of the drain pan 9 , and flows in a water storage tank 7 via a drain discharge port. In this case, in FIG. 10, arrows denote a flow direction of the refrigerant gas or the refrigerant liquid, and the compressor 1 , the blower 5 , an opening degree of the expansion valve 3 and the like are driven by the power source, for example, a power generator having a fuel tank, a fuel battery, a solar battery and a wind power generator.
[0050] Further, in the fresh water generating apparatus in accordance with the present embodiment, a rotational number of the compressor 1 can be freely changed, for example, by using an inverter, that is, when increasing the rotational number, a circulating amount of the refrigerant is increased and an amount of fresh water generated in the evaporator 4 is increased, and when reducing the rotational number, the circulating amount of the refrigerant is reduced and the amount of fresh water generated in the evaporator 4 is reduced, whereby it is possible to control a fresh water generating capacity. In order to control the fresh water generating capacity, in place of changing the rotational number of the compressor 1 , a rotational number of the blower 5 may be changed so as to change a blowing amount of the ambient air in the evaporator 4 and the condenser 2 .
[0051] The condensed water is collected by the drain pan 9 and is stored in the water storage tank 7 . An electric power for driving the compressor and the blower, and further the expansion valve is supplied by the power source 6 . Accordingly, the fresh water generator 10 forming a refrigerant cycle portion having the condenser 2 , the expansion valve 3 , the evaporator 4 and the blower 5 in the fresh water generating apparatus, the power source 6 , a dipping pump 8 moving the condensed water to the water storage tank 7 from the drain pan 9 , and the water storage tank 7 are received in one case 21 .
[0052] [0052]FIGS. 3A, 3B and 3 C show a state that the fresh water generator 10 is received in the case 21 , in which FIG. 3A is a top elevational view, FIG. 3B is a front elevational view and FIG. 3C is a side elevational view. The present case (the storage) is structured such that a heat insulating material 34 is adhered to an inner side thereof, and a ventilating port 31 discharging the ambient air taken in the interior portion is provided on a side surface, thereby preventing a temperature within the storage from being increased. Further, a filter 36 is mounted to a suction port 35 introducing the ambient air, and the ambient air is introduced to the condenser 2 or the evaporator 4 , thereby preventing dusts from getting in from the external portion.
[0053] [0053]FIGS. 4A, 4B and 4 C show another embodiment, in which FIG. 4A is a top elevational view, FIG. 4B is a front elevational view and FIG. 3C is a side elevational view. The heat insulating material 34 is directly wound around an outer panel of the fresh water generator 10 , a blow-off port 32 and the ventilating port 31 are respectively provided in a top surface thereof and a side surface thereof so as to constitute a fresh water generator 41 . The filter 36 for preventing the dusts from getting in is provided in an outer panel, and is directly mounted to the suction port 35 introducing the ambient air. Further, reference numeral 33 denotes a control panel for controlling start, stop and the like of the fresh water generating apparatus. The control panel 33 is provided on a front surface of the fresh water generator 41 or the fresh water generating apparatus 21 , and can be controlled from a front surface.
[0054] As mentioned above, since the fresh water generator 41 receiving the compressor 1 , the condenser 2 , the expansion valve 3 , the evaporator 4 and the blower 5 , having the blow-off port 32 on the upper surface thereof and having the heat insulating material 34 wound around the outer side thereof, the water storage tank 7 and the power source 6 are received in one case 21 , the structure is made compact, and it is possible to set a receiving space to 1600×2300×1150 mm (width×height×depth) in correspondence to 15 horse power for generating the fresh water at a rate of about 500 liters per one day.
[0055] FIGS. 5 to 7 show a state that the fresh water generator 41 is received in the case 21 , in which the power source 6 is constituted by a fuel tank 71 and a power generator 72 , and the case 21 is constituted by a transporting container 61 opened in both side surfaces and double opened in a backward portion. In FIGS. 7A, 7B and 7 C, FIG. 7A is a top elevational view, FIG. 7B is a side elevational view and FIG. 7C is a backward side elevational view (in a state that the doors are opened).
[0056] In the case of placing the fresh water generating apparatus shown in FIG. 5 in the container 61 opened in both side surfaces and double opened in the backward portion as shown in FIG. 6, the apparatus is arranged as shown in FIGS. 7A, 7B and 7 C. The doors in the side surfaces of the container 61 are opened at 90 degrees, and the backward doors are opened in a double hinged manner. Accordingly, it is easy to maintain and operate the inner portion, and since the doors can be closed at a time of driving the fresh water generating apparatus except the maintenance time, it is possible to protect the fresh water generating apparatus. The fresh water generator 41 is received in the container 61 so that the fresh water generator 41 is arranged in a front surface left side in FIG. 7A, the fuel tank 71 is arranged in a backward surface side thereof, the power generator 72 is arranged in a backward surface right side thereof and the water storage tank 7 is arranged in a front surface right side thereof. An electricity generated by the power generator 72 on the basis of the fuel fed from the fuel tank 71 is supplied as a drive source of the fresh water generator 41 . Further, the fresh water is generated from the air sucked from the suction port by using the electric power. The generated fresh water is dipped by the pump 8 and is stored in the water storage tank 7 . In accordance with the apparatus shown in FIG. 7, the operation can be easily performed, and it is possible to smoothly supply the electric power and transfer the generated fresh water.
[0057] In FIGS. 8A, 8B and 8 C, FIG. 8A is a top elevational view, FIG. 8B is a side elevational view and FIG. 8C is a backward side elevational view. The structure is made such that the fresh water generator 41 is surrounded by a partition plate 73 , the side surface door of the fresh water generator 21 is separated into a front surface portion of the fresh water generator 41 and a front surface portion of the water storage tank 7 , whereby it is possible to open only the fresh water generator 41 . Accordingly, the fresh water generating apparatus 21 can be operated by opening only the door in the front surface portion of the fresh water generator 41 , it is possible to prevent the dusts from being mixed into the water storage tank 7 or the fuel tank 71 and it is possible to prevent the fresh water generating apparatus 21 from being deteriorated and troubled, whereby it is possible to secure a reliability.
[0058] In FIGS. 9A and 9B, FIG. 9A is a top elevational view and FIG. 9B is a side elevational view. This structure corresponds to an embodiment in which the fresh water generator 41 is structured such as to be opened in a double hinged manner. Accordingly, it is possible to operate and maintain the fresh water generating apparatus 21 while closing a side surface door in which an area is forced to become wide, and it is easy to avoid an influence of the dusts even during the maintenance.
[0059] As mentioned above, in the desert area where a sea fog is generated at night, by condensing the water content in the ambient air by the fresh water generating apparatus so as to generate the fresh water, providing with the ventilating port and receiving the fresh water generator in the storage (the case) having the heat insulating material adhered to the inner side thereof, the temperature within the fresh water generator is not increased even when the daytime temperature increases near 50 degrees. Further, when the fresh water generating apparatus is controlled so as to be operated after the night when the fog is generated before an early morning and is not operated during the daytime, an energy efficiency is increased. Further, an amount of water collected by the fresh water generating apparatus corresponding to 15 horse power is about 500 liters per one day although a difference exists with the season, however, the fresh water can be evenly generated throughout the year and a salinity is low, so that the fresh water can be sufficiently used as an agricultural water.
[0060] Further, it is possible to self generate even in the developing area to which the electric power can not be supplied, it is possible to introduce the water at any place where the fog is generated, and it is possible to make the equipment space minimum since the fresh water generator and the power source are both loaded in the case. Further, since the fresh water generator is made compact, it is possible to generate the fresh water without increasing the temperature within the storage and it is possible to protect the apparatus even in the desert area where the daytime temperature increases near 50° C.
[0061] In accordance with the present invention, it is possible to obtain the fresh water generating apparatus having an improved fresh water generating efficiency, suitable for generating a lot of fresh water, not depending on an area at a time of placing or the like in correspondence to whether or not the electric power exists, being compact and easily transferred.
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In a fresh water generating apparatus for condensing water content contained in air, there are provided a first heat exchanger having a refrigerant gas flow passage to which a compressed refrigerant gas is introduced, and on an outer side of which air is blown to condense the refrigerant gas, a second heat exchanger having a refrigerant liquid flow passage to which a refrigerant liquid discharged from the first heat exchanger is introduced after a pressure thereof is reduced, and on an outer side of which air is blown to cool the air and condense the water content to produce fresh water, and a power source for compressing the refrigerant gas and blowing the air.
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[0001] This application is a continuation of co-pending application Ser. No. 10/681,700, filed Oct. 8, 2003, issuing as U.S. Pat. No. 7,556,647 on Jul. 7, 2009.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to a device for attaching a first mass to a second mass and methods of making and using the same.
[0004] 2. Description of the Related Art
[0005] Prosthetic heart valves can replace defective human valves in patients. Prosthetic valves commonly include sewing rings, suture cuffs or rings that are attached to and extend around the outer circumference of the prosthetic valve orifice.
[0006] In a typical prosthetic valve implantation procedure, the aorta is incised and the defective valve is removed leaving the desired placement site that may include a fibrous tissue layer or annular tissue. Known heart valve replacement techniques include individually passing sutures through the fibrous tissue or desired placement site within the valve annulus to form an array of sutures. Free ends of the sutures are extended out of the thoracic cavity and laid, spaced apart, on the patient's body. The free ends of the sutures are then individually threaded through a flange of the sewing ring. Once all sutures have been run through the sewing ring (typically 12 to 18 sutures), all the sutures are pulled up taught and the prosthetic valve is slid or “parachuted” down into place adjacent the placement site tissue. The prosthetic valve is then secured in place by traditional knot tying with the sutures. This procedure is time consuming as doctors often use three to ten knots per suture.
[0007] The sewing ring is often made of a biocompatible fabric through which a needle and suture can pass. The prosthetic valves are typically attached to the sewing rings which are sutured to a biological mass that is left when the surgeon removes the existing valve from the patient's heart. The sutures are tied snugly, thereby securing the sewing ring to the biological mass and, in turn, the prosthetic valve to the heart.
[0008] During heart valve replacement procedures, the patient is on heart-lung bypass which reduces the patient's oxygen level and creates non-physiological blood flow dynamics. The longer a patient is on heat-lung bypass, the greater the risk for permanent health damage. Existing suturing techniques extend the duration of bypass and increase the health risks due to heart-lung bypass. Furthermore, the fixturing force created by suturing varies significantly from suture to suture, even for the same medical professional.
[0009] In addition, sutures and other attachment devices are used in a variety of medical applications where the use of the device of the present invention would provide an advantage in fixing a first mass to a second mass, where the first mass is a tissue or a device or prosthesis, and the second mass is a tissue or a device or prosthesis. These applications include anchoring a prosthesis such as a synthetic or autologous graft to surrounding tissue or another prosthesis, tissue repair such as in the closure of congenital defects such as septal heart defects, tissue or vessel anastomosis, fixation of tissue with or without a reinforcing mesh for hernia repair, orthopedic anchoring such as in bone fusing or tendon or muscle repair, ophthalmic indications, laparoscopic or endoscopic tissue repair or placement of prostheses, or use by robotic devices for procedures performed remotely.
[0010] For these indications and others, there is a need for a fixturing device to minimize the time spent fixturing certain devices or conduits, such as a valve prosthesis and a second mass, a vessel to another vessel or anatomical structure, tissue to tissue, surrounding tissue to a second prosthesis, and the like as described above. Furthermore, there is a need for a device that compliments existing suturing or attachment devices and methods and reduces fixturing times. Also, there is a need for a fixturing device that can be easily removed. There also exist a need to provide a fixturing device that can provide a consistent fixturing force.
BRIEF SUMMARY OF THE INVENTION
[0011] A device for connecting a first mass to a second mass is disclosed. The device has a base and a first leg. The base has a base axis, a first end and a second end. The first leg extends from the first end of the base. The device has a first configuration and a second configuration. When the base is rotated with respect to the base axis, the device is in the first configuration. The device can also have a second leg extending from the second end of the base.
[0012] Another device for connecting a first mass to a second mass is disclosed. The device has a base, a first leg and a second leg. The base has a base axis, a first end and a second end. The first leg has a first longitudinal axis and a first leg length. The first leg extends from the first end of the base. The second leg has a second longitudinal axis and a second leg length. The second leg extends from the second end of the base. The first leg length is substantially longer than the second leg length.
[0013] The device can have a first configuration and a second configuration. When the base is rotated with respect to the base axis, the device is in the first configuration.
[0014] Yet another device for connecting a first mass to a second mass is disclosed. The device has a base, a first leg and a second leg. The base is curved. The base has a base diameter, a first end and a second end. The first leg has a first longitudinal axis and a first leg length. The first leg extends from the first end of the base. The second leg has a second longitudinal axis and a second leg length. The second leg extends from the second end of the base. The device has a relaxed configuration. In the relaxed configuration the first leg crosses the second leg at a leg angle. The leg angle is less than 180 degrees.
[0015] The leg angle can be less than or equal to 90 degrees. The leg angle can be less than or equal to 60 degrees. The base diameter can be less than or equal to 0.13 inches. The base diameter can be greater than or equal to 0.08 inches.
[0016] A method of attaching a first mass to a second mass is disclosed. The method uses an attachment device having a base, a first leg, and a second leg. The base has a first end and a second end. The first leg extends from the first end of the base. The second leg extends from the second end of the base. The attachment device has a first configuration and a second configuration. The method includes holding the attachment device in the first configuration. The method also includes twisting the base of the attachment device to force the attachment device into the second configuration. Further, the method includes inserting the attachment device into the first mass and the second mass. The method also includes releasing the attachment device.
[0017] Twisting the base of the attachment device can occur before inserting the attachment device into the first mass. Inserting the attachment device, at least partially, into the first mass can occur before twisting the base of the attachment device.
[0018] Another method of attaching a first mass to a second mass is disclosed. The method includes forcibly holding an attachment device in a second configuration. The attachment device has a first configuration and the second configuration. The method also includes inserting the attachment device into the first mass and the second mass. The method also includes releasing the attachment device into the first configuration.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 is a front view of an embodiment of the attachment device.
[0020] FIG. 2 is a side view of an embodiment of the attachment device.
[0021] FIG. 3 is a bottom view of an embodiment of the attachment device.
[0022] FIGS. 4-10 illustrate embodiments of section A-A of the attachment device.
[0023] FIG. 11 is a front view of an embodiment of the attachment device.
[0024] FIGS. 12 and 13 are bottom views of various embodiments of the attachment device shown in FIG. 11 .
[0025] FIGS. 14 and 15 are front views of various embodiments of the attachment device.
[0026] FIG. 16 is a front perspective view of an embodiment of the attachment device.
[0027] FIG. 17 is a top view of the embodiment of the attachment device shown in FIG. 16 .
[0028] FIG. 18 is a side perspective view of an embodiment of the attachment device.
[0029] FIG. 19 is a side view of the attachment device shown in FIG. 18 .
[0030] FIGS. 20 and 21 are front views of various embodiments of the attachment device.
[0031] FIG. 22 is a front perspective view of an embodiment of the attachment device.
[0032] FIG. 23 is a top view of the embodiment of the attachment device shown in FIG. 22 .
[0033] FIG. 24 is a front view of an embodiment of the attachment device.
[0034] FIG. 25 illustrates an embodiment of a mandrel for manufacturing the attachment device.
[0035] FIGS. 26 and 27 illustrate methods of changing the attachment device from a first configuration to a second configuration.
[0036] FIGS. 28-30 are cross-sections illustrating an embodiment of a method of using the attachment device.
[0037] FIGS. 31-33 are cross-sections illustrating an embodiment of a method of using the attachment device with the pledget shown in full perspective for FIGS. 31 and 32 .
[0038] FIGS. 34-36 are cross-sections illustrating an embodiment of a method of using the embodiment of the attachment device shown in FIG. 14 .
[0039] FIGS. 37-39 are cross-sections illustrating an embodiment of a method of using the embodiment of the attachment device shown in FIGS. 18 and 19 .
[0040] FIGS. 40-42 are cross-sections illustrating an embodiment of a method of using the attachment device.
[0041] FIG. 43 is a cross-section illustrating a method of using the flag.
[0042] FIG. 44 illustrates an embodiment of the tool for deploying the attachment device.
[0043] FIG. 45 illustrates the end of a tool for deploying the attachment device.
[0044] FIGS. 46 and 47 illustrate using the tip of an embodiment of the tool to deploy the attachment device.
DETAILED DESCRIPTION
[0045] FIGS. 1 through 3 illustrate an attachment device 2 . The attachment device 2 can have a base 4 , legs 6 , and a tip 8 at the end of each leg 6 . (Phantom lines delineate the base 4 , legs 6 and tips 8 .) The base 4 , legs 6 and tips 8 can be separate or integral elements. A flag 10 can be attached to, and extend from, the base 4 . The base 4 and/or the legs 6 can be straight or curved.
[0046] The attachment device 2 can be made from a deformable or elastic material or a combination of materials having resulting deformable or elastic properties. The material can be, for example, stainless steel alloys, nickel titanium alloys (e.g., Nitinol), cobalt-chrome alloys (e.g., ELGILOY® from Elgin Specialty Metals, Elgin, Ill.; CONICHROME® from Carpenter Metals Corp., Wyomissing, Pa.), polymers such as polyester (e.g., DACRON® from E. I. Du Pont de Nemours and Company, Wilmington, Del.), polypropylene, polytetrafluoroethylene (PTFE), expanded PTFE (ePTFE), polyether ether ketone (PEEK), nylon, polyether-block co-polyamide polymers (e.g., PEBAX® from ATOFINA, Paris, France), aliphatic polyether polyurethanes (e.g., TECOFLEX® from Thermedics Polymer Products, Wilmington, Mass.), polyvinyl chloride (PVC), polyurethane, thermoplastic, fluorinated ethylene propylene (FEP), extruded collagen, silicone, echogenic, radioactive, radiopaque materials or combinations thereof Examples of radiopaque materials are barium sulfate, titanium, stainless steel, nickel-titanium alloys, tantalum and gold.
[0047] Any or all elements of the attachment device 2 can be a matrix for cell ingrowth or used with a fabric, for example a covering (not shown) that acts as a matrix for cell ingrowth. The fabric can be, for example, polyester (e.g., DACRON® from E. I. du Pont de Nemours and Company, Wilmington, Del.), polypropylene, PTFE, ePTFE, nylon, extruded collagen, silicone or combinations thereof.
[0048] The attachment device 2 and/or the fabric can be filled and/or coated with an agent delivery matrix known to one having ordinary skill in the art and/or a therapeutic and/or diagnostic agent. These agents can include radioactive materials; radiopaque materials; cytogenic agents; cytotoxic agents; cytostatic agents; thrombogenic agents, for example polyurethane, cellulose acetate polymer mixed with bismuth trioxide, and ethylene vinyl alcohol; lubricious, hydrophilic materials; phosphor cholene; anti-inflammatory agents, for example non-steroidal anti-inflammatories (NSAIDs) such as cyclooxygenase-1 (COX-1) inhibitors (e.g., acetylsalicylic acid, for example ASPIRIN® from Bayer AG, Leverkusen, Germany; ibuprofen, for example ADVIL® from Wyeth, Collegeville, Pa.; indomethacin; mefenamic acid), COX-2 inhibitors (e.g., VIOXX® from Merck & Co., Inc., Whitehouse Station, N.J.; CELEBREX® from Pharmacia Corp., Peapack, N.J.; COX-1 inhibitors); immunosuppressive agents, for example Sirolimus (RAPAMUNE®, from Wyeth, Collegeville, Pa.), or matrix metalloproteinase (MMP) inhibitors (e.g., tetracycline and tetracycline derivatives) that act early within the pathways of an inflammatory response. Examples of other agents are provided in Walton et al, Inhibition of Prostoglandin E 2 Synthesis in Abdominal Aortic Aneurysms, Circulation, Jul. 6, 1999, 48-54; Tambiah et al, Provocation of Experimental Aortic Inflammation Mediators and Chlamydia Pneumoniae, Brit. J. Surgery 88 (7), 935-940; Franklin et al, Uptake of Tetracycline by Aortic Aneurysm Wall and Its Effect on Inflammation and Proteolysis, Brit. J. Surgery 86 (6), 771-775; Xu et al, Sp1 Increases Expression of Cyclooxygenase-2 in Hypoxic Vascular Endothelium, J. Biological Chemistry 275 (32) 24583-24589; and Pyo et al, Targeted Gene Disruption of Matrix Metalloproteinase-9 (Gelatinase B) Suppresses Development of Experimental Abdominal Aortic Aneurysms, J. Clinical Investigation 105 (11), 1641-1649 which are all incorporated by reference in their entireties.
[0049] A base axis 12 can extend longitudinally through the transverse cross-sectional center of the base 4 . As shown in FIG. 2 , when viewed from the side, the base axis 12 can form a base plane angle 14 from about 0° to about 30° , for example about 10°. The base 4 can have a base inner radius 16 from about 0.25 mm (0.010 in.) to about 19.1 mm (0.750 in.), for example about 1.91 mm (0.075 in.). The proximal end of the base 4 can be formed into a table 17 . The table 17 can be a flat surface that tapers to the base 4 .
[0050] The base 4 and legs 6 can have a shaft diameter 18 from about 0.03 mm (0.001 in.) to about 6.35 mm (0.250 in.), for example, about 0.51 mm (0.020 in.). The base 4 and legs 6 can have the same or different shaft diameters 18 . A base neutral radius 19 can be the base inner radius 16 and half the shaft diameter 18 . As shown in FIG. 1 , the legs 6 can intersect at a leg angle 20 in or near the plane of the attachment device 2 or in or near the approximate plane of the base 4 . An approximate plane is a plane that can be used whether the base 4 does or does not fall on a flat plane. If the base 4 is a straight line or a point, the approximate plane of the base 4 can be calculated using the points of the legs 6 that are nearest the base 4 and out of line with the base 4 . The leg angle 20 can be from about 180° to about 10°, more narrowly from about 90° to about 60°, for example about 45° or, for example, about 60°.
[0051] The length from an end of the base 4 to a longitudinal leg axis 24 can be a body length 22 . The body length 22 can be from about 0.25 mm (0.010 in.) to about 12.7 mm (0.500 in.), for example about 2.913 mm (0.1147 in.). The length between the distal end of one tip 8 and the distal end of the opposite tip 8 can be a tip distance 26 . The tip distance 26 can be from about 0.03 mm (0.001 in.) to about 25.4 mm (1.000 in.), more narrowly about 1.3 mm (0.050 in.) to about 3.18 mm (0.125 in.), for example about 2.3 mm (0.090 in.).
[0052] The tip 8 can have a tip length 28 from about 0.05 mm (0.002 in.) to about 12.7 mm (0.500 in.), for example about 1.0 mm (0.040 in.). The tip 8 can have a tip angle 30 from about 5° to about 90°, for example about 30°. The tips 8 can be straight, pointed ends, curve out of line (shown by alternative tips 8 a and 8 b, drawn in phantom lines in FIGS. 2 and 3 ) from the nearest end of the leg 6 , or combinations thereof.
[0053] The tips 8 and/or legs 6 can have retention devices 29 . The retention devices 29 can be barbs, spikes, hooks, threads, ribs, splines, a roughened surface, a sintered surface, a covered surface (e.g., with DACRON® from E. I. du Pont de Nemours and Company, Wilmington, Del.) or combinations thereof A retention coating 31 , for example a biodegradable coating or filler such as gel or gelatin or otherwise removable, can be on and/or around and/or near the retention devices 29 . The retention coating 31 (shown in phantom lines) can be configured to render the retention device 29 substantially ineffective until a substantial amount of the retention coating 31 has been biodegraded or otherwise removed.
[0054] The legs 6 can have mechanical interfaces 33 , for example, a slot, snap, protrusion, latch, catch or combinations thereof The interfaces 33 can be aligned so the interface on one leg 6 meets the interface 33 on the other leg 6 at the point where the legs 6 cross. The interfaces 33 can removably attach to each other.
[0055] FIGS. 4 through 10 illustrate examples of cross-section A-A of the legs 6 and/or the base 4 . The cross-section A-A of the legs 6 can be the same or different as the cross-sections of the base 4 . The cross-sections of the base 4 and/or legs 6 can be constant or vary along their respective lengths. FIGS. 4 through 8 , respectively, illustrate circular, rectangular (including square), triangular, substantially flat, and star-shaped or irregular cross-sections A-A. FIG. 9 illustrates an oval cross-section A-A. A ratio of the shaft diameter 18 to the length of a minor axis 32 can be from about 1:1 to about 20:1, for example 10:1.
[0056] FIG. 10 illustrates a cavity 36 inside the cross-section A-A. The cavity 34 can be hollow or can be filled completely or partially. The cavity 34 can be filled with an agent delivery matrix known to one having ordinary skill in the art and/or a therapeutic and/or diagnostic agent and/or echogenic and/or radioactive and/or radiopaque materials, for example, the agents and/or materials listed supra. The type and amount of filling can vary along the length of the base 4 and/or legs 6 . The ratio of the shaft diameter 18 to a cavity diameter 36 can be from about 1:1 to about 50:1, for example, about 2:1.
[0057] FIG. 11 illustrates an attachment device 2 that can have a leg 6 that can have a first leg segment 38 and a second leg segment 40 . The first leg segment 38 can extends from the base 4 . The second leg segment 40 can extend on a proximal end from the first leg segment 38 . The tip 8 can extend from a distal end of the second leg segment 40 . The second leg segment 40 can have a different radius of curvature than the first leg segment 38 and/or form an angle with respect to the first leg segment 40 . FIG. 12 illustrates that the second leg segment 40 can form an angle (shown by arrows) with the approximate plane of the base 4 . FIG. 13 illustrates that the first leg segment 38 can form an angle (shown by arrows) with the approximate plane of the base 4 . The second leg segments 40 can be substantially parallel with the approximate plan of the base 4 .
[0058] FIG. 14 illustrates an attachment device 2 that can have a first leg 6 a that can be substantially longer than a second leg 6 b. The ratio of a first leg-tip length 22 a to a second leg-tip length 22 b can be from about 1:1 to about 10:1, for example, about 3:1.
[0059] FIG. 15 illustrates an attachment device that can have a first leg radius 42 and a second leg radius 44 . The ratio of the first leg radius 42 to the second leg radius 44 can be from about 1:1 to about 50:1, for example about 10:1.
[0060] FIGS. 16 and 17 illustrate an attachment device 2 that can have a “flat top.” The approximate plane of the second leg 6 b can form an angle, for example about 90°, with the approximate plane of the base 4 . When in use, the flat top can further anchor the attachment device 2 against the first mass and/or second mass. FIGS. 18 and 19 illustrate an attachment device 2 that can have arms 6 that can wrap around the base axis 12 .
[0061] FIG. 20 illustrates an attachment device 2 that can have arms 46 that can extend from the base 4 and/or the legs 6 . When deployed, the arms 46 can squeeze tissue between the arms 46 and the legs 6 and/or base 4 for additional retention force. Anchors 48 can extend from the arms 46 , for example at the distal ends of the arms 46 . The anchors 48 can be, for example, hooks, barbs, spikes, staples or combinations thereof The anchors 48 can extend directly from the base 4 and/or legs 6 with or without arms 46 separately attached to the base 4 and/or legs 6 . FIG. 21 illustrates an attachment device 2 that can have a straight base 4 and can have the arms 46 extending from the base 4 .
[0062] FIGS. 22 and 23 illustrate an attachment device that can have first, second and third legs 6 a, 6 b and 6 c. The base 4 can be a platform, wireframe, or point attachment which can be spot-welded or brazed, tube crimped or otherwise mechanically connected. The planes of the legs 6 a, 6 b and 6 c can intersect at substantially equal angles, about 120°, or unequal angles.
[0063] FIG. 24 illustrates an attachment device that can have a first loop 49 and a second loop 51 . The first loop 49 can be formed from the base 4 and a proximal portion of the first leg segments 38 . The second loop 51 can be formed from a distal portion of the first leg segments 38 and a proximal portion of the second leg segments 40 .
Methods of Making
[0064] FIG. 25 illustrates a mandrel 50 that can be used to form the attachment device 2 , for example during heat treatment. The base 4 and/or legs 6 can be held on the mandrel 50 by a single cylinder 52 , a formed path 54 , a pressure plate 56 , for example a washer under a screw or combinations thereof Methods for forming shape memory alloys (e.g., Nitinol) are known to those having ordinary skill in the art. The tips 8 can be formed, for example, by grinding, electropolishing, or precision sharpening (e.g., polishing services from Point Technologies, Inc., Boulder, Colo.) to a satisfactory geometry, including a trocar point, beveled, rounded, tapered, pointed or flattened.
[0065] Other methods known to one having ordinary skill in the art can be used to manufacture the attachment device 2 and/or its elements. For example, manufacturing techniques include molding, machining, casting, forming (e.g., pressure forming), crimping, stamping, melting, screwing, gluing, welding, die cutting, laser cutting, electrical discharge machining (EDM), etching or combinations thereof.
[0066] Any elements, sub-assemblies, or the attachment device 2 as a whole after final assembly, can be coated by dip-coating or spray-coating methods known to one having ordinary skill in the art, utilizing materials such as PTFE (e.g., TEFLON® from E. I. du Pont de Nemours and Company, Wilmington, Del.), polyester (e.g., DACRON® from E. I. du Pont de Nemours and Company, Wilmington, Del.), gelatin, gel, other polymers or combinations thereof One example of a method used to coat a medical device for vascular use is provided in U.S. Pat. No. 6,358,556 by Ding et al. and hereby incorporated by reference in its entirety. Time release coating methods known to one having ordinary skill in the art can also be used to delay the release of an agent in the coating. The coatings can be thrombogenic or anti-thrombogenic.
[0067] The attachment device 2 , or any element thereof (e.g., the base 4 ) can be covered with a fabric, for example polyester (e.g., DACRON® from E. I. du Pont de Nemours and Company, Wilmington, Del.), polypropylene, PTFE (e.g., TEFLON® from E. I. du Pont de Nemours and Company, Wilmington, Del.), ePTFE, nylon, extruded collagen, gel, gelatin, silicone or combinations thereof Methods of covering an implantable device with fabric are known to those having ordinary skill in the art, for example, sintering, spray coating, adhesion, loose covering, dipping or combinations thereof.
Methods of Using
[0068] The attachment device 2 can have a first configuration (e.g., the configuration shown in FIGS. 26 and 27 ) and a second configuration (e.g., the configuration shown in FIGS. 1 through 3 ). The attachment device 2 can have the second configuration when the attachment device is in a relaxed state, with no external forces applied (e.g., prior to insertion or use). The attachment device 2 can have the first configuration when external forces are applied, such as by a delivery tool prior to delivery. When external forces are removed from the attachment device 2 , the attachment device 2 can revert from the first configuration to the second configuration.
[0069] The attachment device can substantially revert to the second configuration even when some permanent hysteresis deformation occurs and/or when a foreign object (e.g., a first and/or second mass) is obstructing the attachment device 2 . When the attachment device 2 has the first configuration, one or both legs 6 can be rotated with respect to the base 4 (e.g., by rotating the base 4 around the base axis 12 , one or both legs 6 splay or separate as they are torqued by the twisting or rotating around of the base).
[0070] FIG. 26 illustrates a method of forcing the attachment device to have the first configuration. The attachment device 2 can be forced to have the first configuration by the application of a base torque, shown by arrows 58 , applied about the base axis 12 . The base torque can be directly applied to the base 4 . The base torque indirectly becomes, or can be applied as, a leg torque, as shown by arrows 60 a and 60 b, to the legs 6 a and/or 6 b about the leg axes 24 a and 24 b. If approximately two times the base neutral radius 19 is less than the tip distance 26 , the legs 6 will splay outward when entering the first mass 68 . If approximately two times the base neutral radius 19 is greater than or equal to the tip distance 26 , the legs 6 will splay inward or stay vertical when deploying into the first mass 68 .
[0071] FIG. 27 illustrates a method of forcing the attachment device to have the first configuration. The attachment device 2 can be forced to have the first configuration by the application of a pivot torque, shown by arrows 62 , applied about the area where the base 4 attaches to the legs 6 , so that the legs 6 are forced to pivot radially outward from each other. The pivot torque can be applied by applying outward translational forces, as shown by arrows 64 , to one or both legs 6 . The pivot torque can be applied by applying translational forces to the base 4 , as shown by arrows 66 .
[0072] As illustrated in FIGS. 28 through 30 , the attachment device 2 can be deployed to attach a first mass 68 to a second mass 70 . The first mass 68 and/or the second mass 70 can be a prosthesis and/or a tissue, or both tissue or both prostheses. The prosthesis can be, for example, cardiac leads, markers, stents, grafts, stent-grafts, heart valves, annuloplasty rings, autografts, allografts, xenografts or any assemblies thereof or combination thereof The tissue can be, for example, vessels, valves, organs (e.g., intestine, heart, skin, liver, kidney, urethra, bone mass, tendon, nerve, muscle), calcified soft tissue or any combination thereof.
[0073] Heart valve assemblies disclosed by Griffin et al. in U.S. Pat. No. 6,241,765, by Lane in U.S. Pat. No. 6,371,983 and by Ritz in U.S. Pat. No. 5,976,183, both of which are hereby incorporated in their entireties, can be placed with the use of the device of the present invention. Other heart valve assemblies that can be used include, for example, the Advantage Bileaflet heart valve, Parallel valve, Freestyle stentless aortic valve, Hancock Porcine heart valve, Hancock apical left ventricular connector model 174 A, Hancock valved conduit models 100 , 105 , 150 , Hall Medtronic heart valve, Hall Medtronic valved conduit, MOSAIC® heart valve and Intact porcine tissue valve (by Medtronic, Inc. Minneapolis, Minn.); Angelini Lamina-flo valve (by Cardio Carbon Company, Ltd., England); Bjork-Shiley single-disk, monostrut and caged-disk valves (Shiley, Inc., now-defunct, previously of CA); Wada-Cutter valve and Chitra Cooley-Cutter valve (by Cutter Biomedical Corp., San Diego, Calif.); Angioflex trileaflet polyurethane valve (by Abiomed, Inc., Danvers, Mass.); ATS AP Series heart valve and ATS Standard heart valve (by ATS Medical, Inc., Minneapolis, Minn.); ANNULOFLO® annuloplasty ring, ANNUFLEX® annuloplasty ring, CARBSEAL® valved conduit, ORBIS® Universal aortic and mitral valve, pediatric/small adult valve, R series valve, SUMIT® mitral valve, TOP HAT® aortic valve, OPTIFORM® mitral valve, MITROFLOW SYNERGY® PC stented aortic pericardial bioprosthesis and the SYNERGY® ST stented aortic and mitral porcine bioprosthesis (by CarboMedics, Inc., Austin, Tex.); ON-X® prosthetic heart valve (by MCRI®, LLC, Austin, Tex.); Starr-Edwards SILASTIC® ball valve, Starr-Edwards 1000, Starr-Edwards 1200, Starr-Edwards 1260, Starr-Edwards 2400, Starr-Edwards 6300, Starr-Edwards 6500, Starr-Edwards 6520, Carpentier-Edwards porcine tissue valve, Carpentier-Edwards pericardial prosthesis, Carpentier-Edwards supra-annular valve, Carpentier-Edwards annuloplasty rings, Duromedics valve and PERIMOUNT® heart valve (by Edwards Lifesciences Corp., Irvine, Calif.); Cross-Jones Lenticular disc valve (by Pemco, Inc.); Tissuemed stented porcine valve (by Tissuemed, Ltd., Leeds, England); Tekna valve (by Baxter Healthcare, Corp., Deerfield, Ill.); Komp-01 mitral retainer ring (by Jyros Medical Ltd., London, England); SJM® Masters Series mechanical heart valve, SJM® Masters Series aortic valved graft prosthesis, ST. JUDE MEDICAL® mechanical heart valves, ST. JUDE MEDICAL® mechanical heart valve Hemodynamic Plus (HP) series, SJM REGENT® valve, TORONTO SPV® (Stentless Porcine Valve) valve, SJM BIOCOR® valve and SJM EPIC® valve (St. Jude Medical, Inc., St. Paul, Minn.); Sorin Bicarbon, Sorin Carbocast, Sorin Carboseal Conduit, Sorin Pericarbon and Sorin Pericarbon Stentless (by Snia S.p.A., Italy). The attachment devices of the present invention may be deployed to implant these various devices in the supra-annular position, or infrannular, depending on the geometry and preferred placement of a particular device. Similarly, it may be advantageous to use the attachment devices 2 of the present invention to secure a sewing ring, or first prosthesis by placing them horizontally or vertically within or around the annulus of such ring, prior to placing a second prosthesis including a valve structure, as provided in U.S. application Ser. No. 10/646,639 filed, 22 Aug. 2003, hereby incorporated by reference in its entirety.
[0074] FIG. 28 illustrates that the attachment device 2 can be held in the first configuration. The attachment device 2 can be fed through a pledget 71 before the attachment device 2 is forced into the first mass 68 . The pledget 71 can be a piece of fabric, for example, a fabric listed supra. The pledget 71 can be loaded onto the attachment device 2 before use. FIG. 29 illustrates that the attachment device 2 can be forced, as shown by arrow 72 , into and through the first mass 68 and part of the second mass 70 . FIG. 30 illustrates that the attachment device 2 can be released from having the first configuration. The attachment device 2 can revert to having substantially the second configuration. A pinching force, shown by arrows, can be applied to the attachment device 2 to encourage additional reversion of the attachment device 2 to having the second configuration. The attachment device 2 shown in FIG. 24 can be deployed in the same manner as described supra, except that the attachment device 2 shown in FIG. 24 can be rotated sufficiently to straighten the first and second loops, before or during deployment.
[0075] The attachment device 2 can be removed and redeployed at any stage of deployment supra, for example, if the surgeon is unsatisfied with the position of the attachment device 2 , or if the prosthesis need replacing or “redoing” at a point in the future. If the attachment device 2 has a retention device 29 , when the retention coating 31 sufficiently biodegrades or is otherwise removed, the retention devices 29 will become exposed and can substantially prevent the removal of the attachment device 2 from the deployment site. Removal may still be achieved however, by apply sufficient force (by a tool or other device) to overcome the strength of the secondary retention element.
[0076] FIGS. 31 though 33 illustrate a method of deploying the attachment device 2 to attach a first mass 68 to a second mass 70 . The pledget 71 can be fed over the attachment device 2 before use. The pledget 2 can be formed as a rectangular container with an access opening 73 , for example a slit, hole, or aperture, to allow access to the base 4 of the attachment device 2 . The attachment device 2 can have the second configuration. The attachment device 2 can be forced, as shown by arrow, so the tips 8 engage the first mass 68 . FIG. 32 illustrates that, with the tips 8 held by the first mass 68 , a longitudinal torque, shown by arrows, applied to the attachment device 2 about a longitudinal axis 74 can then force the attachment device 2 into the first configuration. As illustrated by FIG. 33 , the attachment device 2 can be forced, shown by arrow, through the first mass 68 and part of the second mass 70 . The longitudinal torque (not shown in FIG. 33 ) can be removed during deployment or after the attachment device 2 is completely deployed into the first and second masses 68 and 70 . The pledget 71 can be crushed during deployment.
[0077] FIGS. 34 through 36 illustrate a method of deploying the attachment device shown in FIG. 14 . The first leg 6 a can be forced, as shown by arrow, into and through the first mass 68 and part of the second mass 70 . The first leg 6 a can have a “paddle” (not shown). The paddle can be a flat oval or long rectangular cross-sectional shape on one leg. The paddle can increase resistive force with the first and/or second mass 68 and/or 70 when applying torque to the attachment device 2 .
[0078] FIG. 35 illustrates that the attachment device 2 can be forced into the first configuration by applying a base torque, shown by arrows 58 . The second leg 6 b can then rotate outwardly from the attachment device 2 , as shown by arrow 76 .
[0079] FIG. 36 illustrates that the attachment device 2 can be forced, shown by arrow, through the first mass 68 and part of the second mass 70 . The base torque (not shown in FIG. 36 ) can be removed during deployment or after the attachment device 2 is completely deployed into the first and second masses 68 and 70 .
[0080] FIGS. 37 through 39 illustrate a method of deploying the attachment device 2 shown in FIGS. 18 and 19 . FIG. 37 illustrates that the base 4 and the tips 8 can be placed in contact with or near the first mass 68 . FIG. 38 illustrates that the arms 6 can be rotated, as shown by arrows, about the base axis 12 . The arms 6 can be rotated to cause the arms 6 to be forced into the first mass 68 . FIG. 39 illustrates that the arms 6 can be rotated, as shown by arrows, further about the base axis 12 . The arms 6 can be forced into and through the second mass 70 . The arms 6 can re-enter the first mass 68 .
[0081] FIGS. 40 through 42 illustrate a method of deploying the attachment device 2 to attach a first mass 68 to a second mass 70 . The first mass 68 and the second mass 70 can be two sections of the same object, such as when the attachment device 2 is used to close a wound. FIG. 40 illustrates that the attachment device 2 can be held in the first configuration. FIG. 41 illustrates that the attachment device 2 can be forced, as shown by arrow 72 , so that the first leg 6 a inserts into the first mass 68 and that the second leg 6 b inserts into the second mass 70 . FIG. 42 illustrates that the attachment device 2 can be released from having the first configuration. The attachment device 2 can revert to having substantially the second configuration, causing the legs 6 a and 6 b to rotate inward, shown by arrows 78 , applying force, shown by arrows 80 , to the first mass 68 and the second mass 70 such that the first and second masses 68 and 70 move toward each other.
[0082] The attachment device 2 can be removed from the second mass 70 and/or the first mass 68 , when applicable, by reversing the steps of the deployment methods supra.
[0083] FIG. 43 illustrates that, during use, the attachment device 2 can be covered by new tissue growth 82 . The flag 10 can extend outside of the new tissue growth 82 (as shown) or be located just below the surface but palpable. The flag 10 can act as a marker, palpable or visible by direct vision or imaging modalities known in the art (e.g., x-ray, magnetic resonance imaging (MRI), ultrasound, computed tomography (CT), echocardiogram) for example to locate the attachment device 2 in case of removal of the attachment device 2 . The flag 10 can be made of, for example, suture material (e.g., Nylon, polyglycolic acid, polyester such as DACRON® from E. I. du Pont de Nemours and Company, Wilmington, Del., metals such as those used in the other elements of the attachment device 2 , other polymers or combinations thereof). The base 4 can also serve this function (e.g., of a marker) in some applications.
[0084] FIG. 44 illustrates a tool 84 for deploying the attachment device 2 . The tool 84 can have a first lever 86 and a second lever 88 . The first lever 86 can be rotatably attached to the second lever 88 at a pivot 90 . The first and second levers 86 and 88 can have a handle 92 at each lever's first end and a pad 94 at each lever's second end. The pads 94 can be used to hold the attachment device 2 . When a force is applied to the handles 92 , shown by arrows 96 , the force is transmitted, shown by arrows 98 , to the pads 94 .
[0085] A driver shaft 100 can have a driver handle 102 at a first end and grips 104 at a second end. The pivot 90 can have a longitudinal channel 106 . The driver shaft 100 can pass through the longitudinal channel 106 and/or be rotatably mounted to a case (not shown) fixed to a lever 86 or 88 . The grips 104 can be releasably attached to the attachment device 2 . The attachment device 2 can be rotated about the longitudinal axis 2 by releasing the pads 94 and rotating, as shown by arrows 108 , the driver handle.
[0086] FIG. 45 shows the end of a tool 84 for deploying the attachment device 2 before the attachment device 2 has been loaded into the tool 84 . The tool 84 can have a top part 110 and a bottom part 112 . The top part 110 can be removably attached to the bottom part, as shown by arrow 114 .
[0087] The top part 110 and/or the bottom part 112 can have grooves 116 sized to fit the base 4 and a portion of one or more legs 6 when the attachment device 2 has the first configuration. The attachment device 2 can be forced to have the first configuration and be loaded into the tool 84 , as shown by arrow 118 . The top part 110 can be attached to the bottom part 112 with the attachment device 2 seated (not shown) in the grooves 116 .
[0088] The attachment device 2 can be placed at a desired deployment site by the tool 84 . The device 2 can be deployed from the tool 84 by removing the top part 110 from the bottom part 112 , and removing the tool 84 from the deployment site.
[0089] FIG. 46 illustrates an end of a tool 84 . The tool 84 can have a case 120 with an anvil 122 and leg ports 124 . The case 120 can be slidably attached to a slide 126 . The attachment device 2 can be loaded around the anvil 122 . The legs 6 can protrude from the case 120 through the leg ports 124 .
[0090] FIG. 47 illustrates a method of using the tool 84 of FIG. 46 to deploy the attachment device 2 . The slide 126 can be forced, as shown by arrow 128 , toward the anvil 122 . The slide 126 can push the base 4 against the anvil 122 , causing the legs 6 to rotate outward, as shown by arrows 76 . The surface geometry of the anvil 122 and the slider 126 can match the surface geometry of the attachment device 2 , when the attachment device is fully strained, as shown in FIG. 39 . The attachment device 2 can then be inserted into the desired deployment site (not shown). When the attachment device 2 is in place, the attachment device 2 can be deployed from the tool 84 , for example, by sliding the anvil 122 out of the way (perpendicular to the plane of FIG. 47 ) and forcing the attachment device 2 out the end of the tool 84 with the slide 126 .
[0091] The ends of the tools 84 shown in FIGS. 45 through 47 can be pivoted to the remainder of the tool 84 by methods known to those having ordinary skill in the art. The pivotable end of the tool 84 can improve access to deployment sites not as easily accessible by a non-articulating tool 84 . The tool 84 can be non-articulatable. It would also be possible when access to the site of implantation allows, to employ a tool substantially similar to a needle driver tool known to those skilled in the art.
[0092] Additional disclosure is included in U.S. patent application Ser. Nos. 10/327,821 and 10/646,639, filed 20 Dec. 2002 and 22 Aug. 2003, respectively, which are hereby incorporated by reference in their entireties. It is apparent to one skilled in the art that various changes and modifications can be made to this disclosure, and equivalents employed, without departing from the spirit and scope of the invention. Elements shown with any embodiment are exemplary for the specific embodiment and can be used on other embodiments within this disclosure.
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Devices for attaching a first mass and a second mass and methods of making and using the same are disclosed. The devices can be made from an resilient, elastic or deformable materials. The devices can be used to attach a heart valve ring to a biological annulus. The devices can also be used for wound closure or a variety of other procedures such as anchoring a prosthesis to surrounding tissue or another prosthesis, tissue repair, such as in the closure of congenital defects such as septal heart defects, tissue or vessel anastomosis, fixation of tissue with or without a reinforcing mesh for hernia repair, orthopedic anchoring such as in bone fusing or tendon or muscle repair, ophthalmic indications, laparoscopic or endoscopic tissue repair or placement of prostheses, or use by robotic devices for procedures such as those above performed remotely.
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This is a Divisional Application of parent application Ser. No. 09/731,876, filed Dec. 8, 2000 now U.S. Pat. No. 6,476,007, which claims the benefit of provisional application Ser. No. 60/170,260 filed Dec. 8, 1999.
The U.S. government retains certain rights in the invention according to the provisions and conditions of NIH grants RO1 GM 49111.
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION
Nitric oxide (NO), which serves as an intracellular messenger, is implicated in a number of processes in the central nervous system. In the spinal cord, considerable evidence has demonstrated that NO contributes to the development of hyperalgesia in models of acute and chronic pain (Meller and Gebhart, 1993). Noxious stimulation increased NO synthase (NOS) expression (Lam et al., 1996) and cyclic guanosine 3′,5′-monophosphate (cGMP) content (Garry et al., 1994b) in the spinal cord. Administration of inhibitors of NOS and soluble guanylate cyclase caused analgesic effects (Malmberg and Yaksh, 1993; Meller et al., 1992a, b; Moore et al., 1990). Moreover, NO donors and cGMP analogues applied intrathecally caused a reduction in tail flick or paw withdrawal latency (Garry et al., 1994a; Inoue et al., 1997). Recently, sodium nitroprusside (an NO donor) was shown to evoke the release of immunoreactive cGMP from dorsal horn slices, which was suppressed by the application of methylene blue (a soluble guanylate cyclase inhibitor) (Garry et al., 1994c). These data indicate that the NO/cGMP signaling pathway contributes to spinal hyperalgesia via a cGMP-dependent mechanism.
It has been demonstrated that the N-methyl-D-aspartate (NMDA) receptors play a key role in multisynaptic nociceptive transmission and plasticity within the spinal cord (Aanonsen et al., 1990; Dickenson and Aydar, 1991). The NMDA receptors may be involved in changes such as central sensitization, wind-up, facilitation, hyperalgesia and allodynia, all of which may be manifestations of the same mechanisms. It is found that many of the effects of NMDA receptor activation appear to be ultimately mediated through the production of NO and cGMP (Meller and Gebhart, 1993). In the cerebellum, NMDA receptor activation results in a Ca 2+ -dependent increase in cGMP through the production of NO (Garthwaite et al., 1988). In the spinal cord, NMDA-produced facilitation of the tail flick reflex was completely abolished by pretreatment with either an NOS inhibitor (N G -nitro-L-arginine methyl ester) or a soluble guanylate cyclase inhibitor (methylene blue) (Meller et al., 1992a). Moreover, NMDA has been demonstrated to directly produce the release of NO in vivo at the spinal cord level (Rivot et al., 1999). These results indicate that NMDA may produce thermal hyperalgesia through the activation of the NO/cGMP signaling system in the spinal cord.
The NO/cGMP signaling pathway modifies several intracellular processes including activation of protein kinase, ion channels and phosphodiesterases. cGMP-dependent protein kinases are serine/threonine protein kinases and belong to the large family of protein kinases. cGMP-dependent protein kinases have been found to serve as major effectors for the NO/cGMP signaling pathway in the vascular and nervous system (Meller and Gebhart, 1993). Two isoenzymes of cGMP-dependent protein kinase have been recognized in mammals: cytosolic cGMP-dependent protein kinase I and membrane-bound cGMP-dependent protein kinase II. Furthermore, cGMP-dependent protein kinase I has been shown to exist in two isoforms, designated Iα and Iβ.
Sluka and Willis (1997) reported that the mechanical allodynia induced by capsaicin could be reversed by KT5823, a selective cGMP-dependent protein kinase but not selective cGMP-dependent protein kinase isoform inhibitor. There is a need in the art for drugs which will treat pain without having undesirable side effects.
The nitric oxide/cyclic guanosine monophosphate (NO/cGMP) signaling pathway has become increasingly important as our understanding of its diverse biological actions has expanded, especially within the central nervous system (1, 2). The best understood trigger for the NO/cGMP signaling pathway in the central nervous system is the opening of N-methyl-D-aspartate (NMDA) receptor channels and the activation of NO synthase (NOS) in a Ca 2+ -dependent manner. NO then results in cGMP formation in adjacent neurons through the activation of soluble guanylate cyclase (sGC) (3, 4). Considerable evidence has demonstrated that the NO/cGMP signaling pathway is present in the neurons of the spinal cord and contributes to the development of hyperalgesia in models of acute and chronic pain (4, 5
SUMMARY OF THE INVENTION
It is an object of the invention to provide a method of affecting nociception.
It is an object of the invention to provide a catheter for treating pain.
It is an object of the invention to provide a pharmaceutical composition for treating pain.
It is an object of the invention to provide a method for screening for drugs useful in the treatment of pain.
These and other objects of the invention are provided by one or more of the embodiments described below. In one embodiment of the invention a method of affecting nociception is provided. An analgesic amount of an inhibitor of cyclic guanosine monophosphate (cGMP)-dependent protein kinase Iα (PKGIα) is administered to a patient in need thereof. Desirably, the inhibitor preferentially inhibits isoenzyme I relative to isoenzyme II and inhibits isoform Iα relative to isoform Iβ.
According to another embodiment of the invention another method of affecting nociception is provided. An analgesic amount of Rp-8-[(4-Chlorophenyl)thio]-cGMPS triethylamine (Rp-8-CPT-cGMPS) or other inhibitor of cyclic guanosine monophosphate (cGMP)-dependent protein kinase Iα (PKGIα) is administered intrathecally to a patient in need thereof.
Another aspect of the invention is a catheter. The catheter comprises an analgesic amount of an inhibitor of cyclic guanosine monophosphate (cGMP)-dependent protein kinase Iα (PKGIα). Desirably, the inhibitor preferentially inhibits isoenzyme I relative to isoenzyme II and preferentially inhibits isoform α relative to isoform β.
According to another embodiment of the invention a pharmaceutical composition for treating pain is provided. The composition comprises Rp-8-CPT-cGMPS or another inhibitor of cyclic guanosine monophosphate (cGMP)-dependent protein kinase Iα (PKGIα) in a sterile, pyrogen-free, aqueous vehicle.
In yet another aspect of the invention a method of screening for drugs useful in the treatment of pain is provided. A compound is tested for the ability to inhibit PKG Iα. The compound is also tested for the ability to inhibit PKG Iβ. A compound is identified as a candidate drug useful in the treatment of pain if it selectively inhibits PKG Iα relative to PKG Iβ.
Another embodiment of the invention is another method for screening for drugs useful in the treatment of pain. Cells are contacted with a test compound. Transcription , activity, or translation of PKG Iα is monitored in the cells. A compound is identified as a candidate drug if it inhibits transcription, activity, or translation of PKG Iα.
The present invention thus provides the art with new targets, new drugs, and new methods for treating pain.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 . Time course of the effects of intrathecally injected NOC-12 on the tail-flick latency in rats. Saline control (♦); 10 μg of NOC-12 (▪); 20 μg of NOC-12 (▴); 30 μg of NOC-12 (●). All agents were dissolved in 0.9% saline before injection. Intrathecal NOC-12 produced curtailment of the tail-flick latency in a dose-dependent manner. Data represent the mean±S.E.M. **p<0.01 vs saline-treated groups. †† p<0.01 compared with pre-examination (0 min) value in the same group.
FIG. 2 . Effect of intrathecally administered Rp-8-p-CPT-cGMPS on NOC-12-induced facilitation of the tail-flick latency when tested 30 and 60 min after the intrathecal administration of NOC-12. Data represent the mean±S.E.M. **p <0.01 or *p<0.05 vs saline control groups. ## p<0.01 vs NOC-12-treated groups.
FIG. 3 . Effects of MK-801 and Rp-8-p-CPT-cGMPS on NMDA-induced facilitation of the tail-flick latency when tested 30 min after the intrathecal administration of 10 pg NMDA. Data represent the mean±S.E.M. **p<0.01 or *p<0.05 vs saline-treated groups. ## p<0.01 vs NMDA-treated groups.
FIG. 4 . Photomicrographs showing the distribution of PKGIα immunoreactivity in the dorsal horn at different spinal segments. Cervical FIG. 4A ), thoracic FIG. 4B ), lumbar FIG. 4C ) and sacral FIG. 4D ) segments. PKGIα immunoreactivity was located mainly in the superficial laminae. a, c and d were high magnification of A, C and D, respectively, showing PKGIα-IR neuronal bodies (arrows). Scale bar: 200 μm.
FIG. 5 Effect of intrathecally administered Rp-8-p-CPT-cGMPS (10, 20 and 30 μg) on formalin-induced nociception in the rat. The number of flinches and shakes produced by formalin was counted as described under Methods. **p<0.01 for Rp-8-p-CPT-cGMPS-treated groups vs water-treated control groups.
FIG. 6 . Photomicrographs showing the distribution of Fos-positive neurons in the dorsal horn of the fifth lumbar segment. ( FIG. 6A ) In intrathecally water-treated animals, numerous Fos-positive neurons were observed in the dorsal horn, particularly in laminae I, II, V and VI. ( FIG. 6B ) In intrathecally Rp-8-p-CPT-cGMPS (30 μg)-treated animals, the number of Fos-positive neurons was significantly decreased in the dorsal horn compared to ( FIG. 6A ). Scale bar: 200 μm.
FIG. 7 Effect of intrathecally administered Rp-8-p-CPT-cGMPS (10, 20 and 30 μg) on formalin-induced c-fos expression in the rat. Number of Fos-positive neurons in laminae I–II, III–IV and V–VI was significantly decreased (*p<0.05, **p<0.01) after intrathecal administration of Rp-8-p-CPT-cGMPS (20 μg and 30 μg) when compared to tissues from water pretreated rats. A low dose of Rp-8-p-CPT-cGMPS (10 μg) was ineffective. There was no significant reduction of the number of Fos-positive neurons in laminae VII–X treated with Rp-8-p-CPT-cGMPS and water.
FIG. 8 . Expression and quantitative changes of PKGIα in the lumbar enlargement segments of the spinal cord from control animals (0 hour) and treated animals 24, 48 and 96 hours after saline or formalin injection. The upper panel ( FIG. 8A ) depicts a representative western blot, in which the normal lung (L) was used as a positive control for PKGIα. The lower panel ( FIG. 8B ) is the statistical summary of the densitometric analysis expressed relative to normal control groups. *p<0.05 for formalin-treated groups vs corresponding saline-treated groups. #p<0.05 for formalin-treated groups vs corresponding normal control groups
FIG. 9 Distribution of PKGIα immunoreactivity in the fifth lumbar segment of the spinal cord from treated animals 96 hours after formalin injection ( FIG. 9A , FIG. 9B ). ( FIG. 9A ) the ipsilateral side; ( FIG. 9B ) the contralateral side. There was a significant increase in optical density of PKGIα immunoreactivity throughout the superficial laminae on the formalin-treated side ( FIG. 9A ) but not on the normal side. Saline-treated animals did not show any changes in the optical density of PKGIα immunoreactivity on either side of the lumbar spinal cord. Scale bar: 200 μm.
FIG. 10 . Effects of intraperitoneally administered MK-801, 7-NI and ODQ on the PKGIα expression in the lumbar enlargement segments of the spinal cord from treated animals 96 hours after formalin injection. A representative western blot is shown. Lane I: group 1 (control); Lane II: group 2; Lane III: group 3; Lane IV: group 4; Lane V: group 5.
DETAILED DESCRIPTION OF THE INVENTION
It is a discovery of the present inventors that activation of cGMP-dependent protein kinase Iα is required for NMDA or nitric oxide produced hyperalgesia. It is a further discovery of the inventors that such hyperalgesia can be treated using inhibitors of PKG Iα. Any such inhibitor can be used, however preferred properties include relative non-inhibition of the PKG Iβ isoform, and the PKG II isoenzyme. In addition the inhibitor should not affect either cAMP-dependent protein kinases or cGMP phosphodiesterases. A particularly suitable compound according to the invention is Rp-8-p-CPT-CGMPS. (Also known as Rp-8-[(4-Chlorophenyl)thio]-guanosine 3′,5′-cyclic monophosphothioate triethylamine; Rp-8-p-CPT-cGMPS
Rp-8-[(4-Chlorophenyl)thio]-guanosine-cyclic 3′,5′-hydrogen phosphorothioate.) It has the additional desirable properties of solubility in water or saline, no observed side-effects, and no effect on the cardiovascular system. Other inhibitors can be identified as described here. Attractive candidates for testing are other analogues of cGMP. Particularly attractive candidates are those which interact with the active site of PKG Iα. Such inhibitors are useful clinically to decrease the need for anesthetics, particularly inhalational anesthetics and to reduce acute and chronic pain.
Applicants do not wish to be bound by any particular theory regarding mechanism of action. However, the data collected suggest the following model for nociceptive reflexes produced by NMDA in the spinal cord: NMDA receptor activation increases intracellular Ca 2+ content which activates the calmodulin site on neuronal NOS to produce NO from the amino acid precursor, L-arginine. NO then activates soluble guanylate cyclase to increase intracellular content of cGMP, which results in the activation of cGMP-dependent protein kinase Iα within the target cells.
Nociception is the ability to feel pain. Any noxious stimulation of the neuronal system, especially of the spinal cord is contemplated for treatment within the scope of the invention. The pain can be acute or chronic, involving inflammation or mechanical impinging on a nerve.
Administrations of analgesics and inhibitors according to the invention can be by any means known in the art, so long as the agents are able to reach their targets. Thus agents can be administered without limitation intravenously, intracerebrally, intrathecally, transdermally, intraarterially, topically, subcutaneously, intradermally, orally, nasally, by inhalation, or intramuscularly. Administration may be given once, repeatedly, or chronically. For intrathecal administration a special catheter can be used. The catheter can be loaded with a suitable inhibitor or agent according to the invention. The catheter can be loaded by the operator or can come from the manufacturer preloaded with a suitable dosage. The design and requirements for catheters for intrathecal administration are known in the art.
Suitable agents according to the invention are inhibitors of cyclic guanosine monophosphate (cGMP)-dependent protein kinase Iα (PKGIα). The inhibitor preferentially inhibits isoenzyme I relative to isoenzyme II and inhibits isoform α relative to isoform β. The ratio of inhibition desirable is as high as possible, but suitable ratios include at least 2:1, at least 5:1, at least 10:1, and at least 20:1. The inhibitor preferably does not inhibit cAMP-dependent protein kinase or cGMP-dependent phosphodiesterases. A preferred compound according to the invention is Rp-8-[(4-Chlorophenyl)thio]-cGMPS triethylamine (Rp-8-CPT-cGMPS). Pharmaceutical formulations can be made for treating pain in humans comprising Rp-8-CPT-cGMPS in a sterile, pyrogen-free aqueous vehicle. Any such pharmaceutically acceptable vehicle can be used, so long as it is suitable for the mode of administration to be used. For example, for injections, the vehicle must be pyrogen-free.
In some situations, the patient is also being treated with an anesthetic. The co-administration of an inhibitor of the present invention has the desirable effect of reducing the patient's threshold for the anesthetic. Thus less anesthetic can be used to achieve similar results using the specific inhibitors of the present invention. Co-administration may be separated in time, so long as the effect of the inhibitor is to lower the anesthetic threshold in the individual receiving both agents. Thus the inhibitor may be delivered before, after, or simultaneously with the the anesthetic, although administrations within about 24 hours are desirable. Suitable anesthetics include those standardly administered by inhalation as well as narcotic based anesthetics.
Pain patients can also be treated with other compounds which inhibit other enzymes in the pathway elucidated. Such inhibitors include any that inhibit NMDA receptors, neuronal nitric oxide synthase, or guanylyl cyclase. Numerous inhibitors of these proteins are known in the art and any can be used to more potently close down the pathway shown here to be involved in nociception.
Dosages can be readily determined by those of skill in the art and will depend on the particular route of administration. In rats, amounts between 1 and 100 μg were delivered intrathecally. For humans corresponding amounts will typically be in the range of 50 μg and 100 μg, depending on size of the human.
The biochemical pathway which has been demonstrated as involved in nociception is also implicated in inflammation, neuronal injury, and post-ischaemic injury. Thus the inhibitors of the present invention can also be administered to patients experiencing such disease conditions. Treatment of such inhibitors will ameliorate disease conditions and reduce symptom severity.
The findings of the present inventors lead to a number of preferred methods for identifying additional compounds which can be used similarly to Rp-8-CPT-cGMPS for treating pain and reducing the threshold for anesthetics. In one such method a compound is tested for the ability to inhibit PKG Iα and PKG Iβ. A compound is identified as a candidate drug useful in the treatment of pain if it selectively inhibits PKG Iα relative to PKG Iβ. Suitable selectivity ratios are at least 2, at least 5, at least 10, and at least 20. Selectivity is beneficial to reduce the possibility of unwanted side effects. Compounds can also be tested for the ability to inhibit PKG II. A compound which does not inhibit PKG II or inhibits PKG II less strongly than PKG Iα is desirable.
Another way to screen for additional selective inhibitors of PKG Iα employs whole cells. The cells can be contacted with a test compound. Transcription of PKG Iα gene or translation of PKG Iα or acitivity of PKG Iα in the cells is monitored. Any method known in the art for detecting a specific mRNA or protein can be used. These include without limitation, Northern blots, RT-PCR, western blots, immunoprecipitation, in situ hybridization, ELISA assay, enzyme assays, etc. A compound is identified as a candidate drug if it inhibits transcription, activity, or translation of PKG Iα. Specific inhibition is desirable. Thus it is desired that compounds identified not be general inhibitors of transcription, enzyme activity, or translation, but that they be specific for the gene/enzyme target. Specificity can be monitored and determined using control genes/proteins. The most stringent test for specificity is comparing the activity of the test compounds to related isoenzymes and isoforms, such as PKG II, PGK Iβ, as well as related enzymes such as cAMP-dependent protein kinase and cGMP-dependent phosphodiesterase.
The following examples are provided by way of illustration and to provide experimental and manipulative details. They are not intended to define or limit the invention, which are defined by the claims.
EXAMPLES
Example 1
Materials and Methods
1.1 Animals. Male Sprague-Dawley rats (250–300 g) were housed in different cages on a standard 12 h/12 h light-dark cycle, with water and food pellets available ad libitum. The experiments were carried out with the approval of the Animal Care Committee at the University of Virginia and were consistent with the ethical guidelines of the National Institutes of Health and the International Association for the Study of Pain.
1.2 Immunohistochemistry. For PKGIα and Iβ immunohistochemistry, fifteen animals were deeply anesthetized with pentobarbital sodium (60 mg/kg i.p.) and perfused with 4% paraformaldehyde in phosphate buffer (0.1M, pH 7.4) at 0 h and 96 h after injection of saline (100 μl, 0.9%) or formalin (100 μl, 4%) into a hind paw. The whole spinal cord was removed, postfixed in the same fixative solution for 4 h, cryoprotected by immersing in 30% sucrose overnight at 4° C. and frozen-sectioned at 30 μm. Sections were processed for immunohistochemistry with the use of the conventional avidin-biotin-complex method (26). In brief, sections were incubated in polyclonal rabbit anti-PKGIα antibody (1:800; StressGen Biotechnologies Corp, Victoria, Canada) or in polyclonal rabbit anti-PKGIβ antibody (1:800; StressGen Biotechnologies Corp, Victoria, Canada) diluted in 0.01M phosphate-buffered saline (pH 7.4) containing 3% normal goat serum and 0.25% Triton X-100 for 48 h at 4° C., and then in biotinylated goat anti-rabbit IgG (1:200, Vector Lab) for 1 h at 37° C. and in avidin-biotin-peroxidase complex (1:100; Vector Lab) for 1 h at 37° C. The immune reaction product was visualized by catalysis of 3,3-diaminobenzidine by horseradish peroxidase in the presence of 0.01% H 2 O 2 .
For Fos immunohistochemistry, rats were perfused one hour after the behavioral test was done as described below. The lumbar spinal cord was removed and cut into 30 μm transverse sections. Sections were processed following the above-mentioned procedures except that the primary antibody was substituted with polyclonal rabbit anti-Fos antibody (1:4,000, Santa Cruz Biotechnology, Inc., CA).
Specificity controls for all antisera included the immunoadsorption of the primary antisera with excess of relevant antigens, the substitution of normal sera for the primary antisera and the omission of the primary antisera. All of these controls were negative revealing no sign of an immunohistochemical reaction.
1.3 Behavioral testing. The rats were implanted with an intrathecal catheter under pentobarbital anesthesia. A polyethylene (PE-10) tube was inserted into the subarachnoid space at the rostral level of the spinal cord lumbar enlargement through an incision at the atlanto-occipital membrane according to the method of Yaksh and Rudy (27). The animals were allowed to recover for 7 to 10 days before being used experimentally. Rats showing neurological deficits postoperatively were discarded.
The agent administered intrathecally was a selective, potent and cell-permeable inhibitor of PKGIα, Rp-8-[(4-Chlorophenyl)thio]-cGMPS triethylamine, (Rp-8-p-CPT-cGMPS) (RBI, MA) (28). The drug was dissolved in distilled water before administration. The animals were randomly assigned into four groups as follows: distilled water (control) (n=12); 10 μg of Rp-8-p-CPT-cGMPS (n=6); 20 μg of Rp-8-p-CPT-cGMPS (n=6); 30 μg of Rp-8-p-CPT-cGMPS (n=6). The drug solution was injected intrathecally in a volume of 10 μl, followed by an injection of 10 μl of distilled water to flush the catheter. Fifteen minutes later, formalin (100 μl, 4%) was injected into a hind paw of the rat. In addition, four rats were alone treated intrathecally with Rp-8-p-CPT-cGMPS (30 μg) and another four rats were normal without any treatment.
Immediately following the formalin injection, each individual rat was placed in a transparent cage for observation of the formalin-injected paw. The pain-related behaviors, flinches and shakes, were assessed for the next 60 min by an experimenter who was unaware of the group assignment. The observational session was divided into two periods: a phasic period (0–10 min) and a tonic period (10–60 min). The mean number of flinches and shakes for each period of each treatment group was determined
1.4 Western blot analysis. Thirty five rats were sacrificed by decapitation at 0 h (normal control), 24 h, 48 h and 96 h after injection of saline (100 μl) or formalin (100 μl, 4%) into a hind paw. Lumbar enlargement segments of the spinal cord were dissected, quickly frozen in liquid nitrogen and stored at −80° C. for later use. Frozen tissues were homogenized in the homogenization buffer (50 mM Tris-HCl, 0.1 mM EDTA, 0.1 mM EGTA, 1 mM phenylmethylsulfonyl fluoride, 1 μM leupeptin, 2 μM pepstatin A, 0.1% 2-mercaptoethanol). The crude homogenate was centrifuged at 4° C. for 15 min at 3,000×g. The supernatants (100 μg) were heated for 5 min at 90° C. and then loaded onto 4% stacking/7.5% separating SDS-polyacrylamide gels. The proteins were electrophoretically transferred onto nitrocellulose membrane and blocked with 2% non-fat dry milk and subsequently incubated for 1 h with polyclonal rabbit anti-PKGIα antibody (1:500) and with monoclonal mouse anti-endothelium NOS (eNOS) antibody (1:500) (Transduction Labs). Normal lung was used as a positive control. Specific proteins were detected using horseradish peroxidase-conjugated anti-rabbit or anti-mouse secondary antibody and visualized using chemiluminescence reagents provided with the ECL kit (Amersham Life Sciences Inc, Il) and exposure to film. The intensity of blots was quantified with densitometry (Personal Densitometer/IMAGEQUANT; Molecular Dynamics).
In some experiments, rats were injected intraperitoneally (i.p.) with an NMDA receptor antagonist, MK-801 (RBI, MA), a selective neuronal NOS inhibitor (nNOS), 7-Nitroindazole (7-NI, Alexis Biochemicals, CA) and a selective sGC inhibitor, 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ, Alexis Biochemicals, CA), each day for 4 days (96 h). The doses of MK-801, 7-NI and ODQ used in the present study were determined regarding to the previous studies (29–31). The experiments were divided into five groups. Group 1 (n=4) as control: i.p. injection of saline (0.9%, 2 ml) or peanut oil (2 ml) 30 min prior to the subcutaneous injection of saline (0.9%, 100μ). Groups 2 (n=4): i.p. injection of saline (0.9%, 2 ml) or peanut oil (2 ml) 30 min prior to the subcutaneous injection of formalin (4%, 100 μl). Groups 3, 4 and 5: i.p. injection of MK-801 (2 mg/kg in 2 ml saline, n=4), 7-NI (100 mg/kg in 2 ml peanut oil, n=4) and ODQ (100 mg/kg in 2 ml peanut oil, n=4), respectively, 30 min prior to the subcutaneous injection of formalin (4%, 100 μl). Lumbar enlargement segments were removed and western blot analysis was employed in the same manner as above.
1.5 Statistical analysis. The results from the immunohistochemistry, behavioral tests and western blot were statistically assessed by an analysis of variance. Intergroup differences were analyzed by the Newman-Keuls test. Data were assessed as mean±S.E.M. Significance was set at p<0.05.
Results
1.6 Distribution of PKGIα and Iβ Immunoreactivity in the Spinal Cord
Immunohistochemical analysis revealed PKGIα immunoreactivity in the neuronal bodies and processes and in specific lamina in the spinal cord of the normal rats. The PKGIα immunoreactive ((PKGIα-IR) fibers were concentrated in the superficial laminae of the spinal cord. The PKGIα-IR fibers of varying density were noted in all segments of the spinal cord. Usually, the highest density of PKGIα-IR fibers occurred in the cervical and thoracic segments ( FIGS. 1A and 1B ), the moderate density in the lumbar segments ( FIG. 1C ) and the lowest density in the sacral segments ( FIG. 1D ). A few isolated PKGIα-IR fibers were noted in the deep laminae of the dorsal horn, particularly in the cervical and thoracic segments.
Similar to the distribution of PKGIα-IR fibers, PKGIα-IR neurons also were seen in all segments of the spinal cord. These PKGIα-IR neurons were small (<20 μm) and appeared either oval, fusiform or round with few neuronal processes. Since the density of PKGIα-IR fibers was relatively lower at the sacral level, many PKGIα-IR perikarya were observed clearly in the sacral segments ( FIG. 1 d , arrows). At the other segment levels, higher density of PKGIα-IR fibers made most PKGIα-IR perikarya difficult to be observed. Only some PKGIα-IR perikarya were seen in the superficial laminae under high magnification ( FIG. 1 a and 1 c , arrows). A few weakly stained PKGIα-IR cells were noted in the ependymal cell layer around the central canal, in the intermediolateral nucleus and in the lateral spinal nucleus. No PKGIα-IR neurons were found in the deep laminae of the dorsal horn, the ventral horn or the white matter.
PKGIβ immunoreactivity was not detected or very weakly detected in all laminae of the spinal cord.
1.7 Effect of Rp-8-p-CPT-cGMPS on Formalin-induced Pain Behavior
Pretreatment with a selective PKGIα inhibitor, Rp-8-p-CPT-cGMPS, produced significant and dose-dependent decreases of formalin-induced pain behavior ( FIG. 2 ). Intrathecal Rp-8-p-CPT-cGMPS at 30 μg reduced the number of flinches and shakes evoked by formalin by 64% (p<0.01) and 66% (p<0.01) in the phasic and tonic periods of the formalin test, respectively. Rp-8-p-CPT-cGMPS given at 20 μg dramatically suppressed the formalin-induced behavior by 25% (p<0.01) in the tonic period, but had no effect in the phasic period. 10 μg dose of Rp-8-p-CPT-cGMPS did not influence the formalin response in either the phasic or the tonic periods of the formalin test.
1.8 Effect of Rp-8-p-CPT-cGMPS on Formalin-induced c-fos Expression in the Spinal Cord
Numerous Fos-positive neurons were observed in the ipsilateral side of the spinal cord, while fewer Fos-positive neurons were detected in the contralateral side following the injection of formalin into a hind paw. Many Fos-positive neurons were distributed in the medial region of the superficial laminae and laminae V and VI, a few in laminae III, IV and X, and fewer in laminae VII–X ( FIG. 3A ). There were no Fos-positive neurons in the rats without any treatment or only with the treatment of Rp-8-p-CPT-cGMPS.
Administration of Rp-8-p-CPT-cGMPS also significantly and dose-dependently attenuated formalin-induced c-fos expression in all laminae except for the ventral horn and the lamina X in the spinal cord ( FIGS. 3B and 4 ). With a large dose of Rp-8-p-CPT-cGMPS (30 μg), the mean reduction in number of Fos-positive neurons per section was 29% in the superficial laminae, and 30% in the nucleus proprius and 51% in the neck of dorsal horn as compared to the control group. The depression was statistically significant in the three regions (p<0.05). However, a low dose of Rp-8-p-CPT-cGMPS (10 μg) failed to produce any significant change of the amount or distribution of Fos-positive neurons as compared to the control group.
1.9 Upregulation of PKGIα Expression in the Spinal Cord After Formalin Injection
Abundant PKGIαprotein was detected only in the tissues from 96 h formalin-treated rats, while low levels were detected in tissues from the normal control rats, 24 h and 48 h formalin-treated rats and 24 h, 48 h and 96 h saline-treated rats ( FIG. 5 ). Quantitation showed that the PKGIα protein levels were respectively 1.70- and 1.55-fold greater in tissues from the 96 h formalin-treated group (n=5) than those in tissues from the normal control (n=5) and the 96 h saline-treated (n=5) groups. The statistical analysis showed a significant difference (p<0.05) ( FIG. 5 ). Tissues from the 24 h (n=5) and 48 h (n=5) formalin-treated groups contained 1.25- and 1.07-fold more PKGIα protein than those from the 24 h (n=5) and 48 h (n=5) saline-treated groups, but the increases were not statistically significant (p>0.05) ( FIG. 5 ). The PKGIα protein levels also did not differ significantly in tissues from 24 h and 48 h formalin- or saline-treated animals and the normal control animals (p>0.05) ( FIG. 5 ).
In the 96 h formalin-treated rats, the optical density of PKGIα immunoreactivity (fibers and cell bodies) increased throughout the superficial laminae in the lumbar segments. Particularly in the medial region of the superficial laminae, the dense PKGIα-IR fibers were observed ( FIG. 6C ) compared to those in the control or saline-treated groups. Under high magnification, some weakly staining PKGIα-IR perikarya were also found in the medial region of the superficial laminae. These changes occurred only on the ipsilateral side, not on the contralateral side ( FIGS. 6C and D). The 96 h saline-treated animals did not show any changes in the optical density of PKGIα immunoreactivity on either side of the lumbar spinal cord ( FIGS. 6A and B).
1.8 Effects of MK-801, 7-NI and ODQ on Formalin-induced Upregulation of PKGIα Expression in the Spinal Cord
As shown in FIG. 7 , after i.p. pretreatment with vehicle (saline or peanut oil), the tissues from 96 h formalin-treated rats (group 2) still displayed more abundant PKGIα protein in comparison with those from 96 h saline-treated rats (group 1). Quantitation showed that PKGIα protein level in group 2 was 1.52-fold greater than that in group 1. The statistical analysis showed significant difference between the two groups above (p<0.05). However, following i.p. pretreatment with MK-801, 7-NI or ODQ, the tissues from 96 h formalin-treated rats (groups 3, 4 and 5) did not show marked increase in PKGIα protein ( FIG. 7 ). Quantitation revealed that the PKGIα protein levels in groups 3, 4 and 5 were respectively 1.13, 1.17 and 1.14-fold greater than that in group 1, but the increases were not statistically significant (p>0.05) ( FIG. 7 ).
Example 2
The previous example showed that cGMP-dependent protein kinase Iα but not Iβ was distributed primarily in the superficial laminae of the spinal cord. The purpose of the present study was to determine whether the thermal hyperalgesia produced by NMDA or NO is mediated through the activation of cGMP-dependent protein kinase Iα
Materials and Methods
2.1. Subjects
Male Sprague-Dawley rats weighing 250–300 g were used. They were kept under a standard 12 h/12 h light-dark cycle, with water and food pellets available ad libitum. The experimental procedures were approved by the Animal Care Committee at the Johns Hopkins University and were consistent with the ethical guidelines of the National Institute of Health and the International Association for the Study of Pain.
The agents administered intrathecally in the present study were Rp-8-[(4-Chlorophenyl)thio]-cGMPS triethylamine (Rp-8-p-CPT-cGMPS, a selective and potent cGMP-dependent protein kinase Iα inhibitor) (RBI, MA, USA), N-ethyl-2-(1-ethyl-2-hydroxy-2-nitrosohydrazino)ethanamine (NOC-12, an NO donor) (Alexis Biochemicals, CA, USA), NMDA (an NMDA receptor agonist) (RBI, MA, USA) and dizocilpine maleate (MK-801, a selective NMDA receptor antagonist) (RBI, MA, USA).
2.2. Surgery
Rats were anesthetized by intraperitoneal injection of pentobarbital sodium (45 mg/kg). Chronic intrathecal catheters were inserted by passing a polyethylene-10 (PE-10) catheter through an incision in the atlanto-occipital membrane to a position 8 cm caudal to the cisterna at the level of the lumbar subarachinoid space. The animals were allowed to recover for a week before experiments were initiated. Rats showing neurologic deficits post-operatively were removed from the study.
2.3. Thermal Nociceptive Test
Nociception was evaluated by the radiant heat tail-flick test with no anesthesia. Each rat was placed in an Animal Holder (IITC Life Science, CA, USA), 690 cm 3 in capacity with rubber stoppers in both ends with a rostral inlet and a caudal outlet. The tail of the rat protruded through the caudal hole. The tail-flick apparatus (Model 33B Tail Flick Analgesy Meter, IITC Life Science, CA, USA) generated a beam of radiant heat which was focused on the underside of the tail, 5 cm from the tip. A cut-off time latency of 13.5 s was used to avoid tissue damage to the tail. Nociception was assessed by the prolongation of the time required to induce tail-flick after applying radiant heat to the skin of the tail. The latency of reflexive removal of the tail from the heat was measured automatically to the nearest 0.01 s. Tail-flick latency was measured six times and the basal latency was defined as the mean of the last five times. The tail-flick data are expressed as percentage change calculated by the formula: (trial latency−baseline latency)/(baseline latency)×100%.
2.4. Drug Treatment
The rats were randomly assigned into fifteen groups as follows: saline (control) (n=6); 7.5 μg of Rp-8-p-CPT-cGMPS (n=6); 15 μg of Rp-8-p-CPT-cGMPS (n=6); 30 μg of Rp-8-p-CPT-cGMPS (n=6); 10 μg of NOC-12 (n=6); 20 μg of NOC-12 (n=6); 30 μg of NOC-12 (n=6); 7.5 μg of Rp-8-p-CPT-cGMPS and 30 μg of NOC-12 (n=6); 15 μg of Rp-8-p-CPT-cGMPS and 30 μg of NOC-12 (n=6); 30 μg of Rp-8-p-CPT-cGMPS and 30 μg of NOC-12 (n=6); 15 pg of NMDA (n=5); 34 pg of MK-801 and 15 pg of NMDA (n=5); 7.5 μg of Rp-8-p-CPT-cGMPS and 15 pg of NMDA (n=5); 15 μg of Rp-8-p-CPT-cGMPS and 15 pg of NMDA (n=5); 30 μg of Rp-8-p-CPT-cGMPS and 15 pg of NMDA (n=5). The dose and time point of maximal effect of NMDA used above was determined based on a previous study (Siegan and Sagen, 1995). The drug solution was injected intrathecally in a volume of 10 μl, followed by an injection of 10 μl of saline to flush the catheter. The tail-flick test was conducted before injection and 15, 30, 60, 90 and 120 min after injection.
2.5. Data Analysis
Data were expressed as the mean±S.E.M. The results were assessed by an analysis of variance followed by Newman-Keuls test. Significance was set up at p<.
Results
No significant change in the tail-flick latency was seen before and after the injection of saline ( FIG. 1 , p>0.05). The intrathecal administration of NOC-12 produced a dose-dependent decrease of the tail-flick latency during the period from 15 to 90 min with a maximum effect at 60 min (The baseline tail flick latency was maximally reduced from 6.53±0.28 to 4.65±0.32 seconds with the use of 30 μg NOC-12. FIG. 1 , p<0.01). The maximal decreases in the tail-flick latency (%) after administration of 10, 20 and 30 μg of NOC-12 were 5.4%, 18.5% ( FIG. 1 , p<0.01) and 24.9% ( FIG. 1 , p<0.01), respectively, compared to control (saline-treated group). The hyperalgesia evoked by NOC-12 was no longer observed 120 min after intrathecal injection.
Three doses of Rp-8-p-CPT-cGMPS (7.5, 15 and 30 μg) given alone had no significant effect on the baseline tail-flick latency between 15 and 120 min. after administration (p>0.05). However, pretreatment (10 min prior) with two high doses of Rp-8-p-CPT-cGMPS (15 and 30 μg) significantly blocked the NOC-12-induced decrease in the tail-flick latency when tested 30 and 60 min after the administration of 30 μg of NOC-12 ( FIG. 2 , p<0.01), although a low dose of Rp-8-p-CPT-cGMPS (7.5 μg) did not influence the hyperalgesia induced by NOC-12 ( FIG. 2 , p>0.05).
Consistent with the previous results (Meller et al., 1992a,b; Siegan and Sagen, 1995), intrathecal administration of NMDA induced a significant facilitation of the tail-flick reflex (The baseline tail-flick latency was reduced from 6.58±0.57 to 4.88±0.41 seconds. FIG. 3 , p<0.01). The NMDA-produced facilitation of the tail-flick reflex was not only completely abolished by prior treatment with NMDA receptor antagonist, MK-801( FIG. 3 , p<0.01), but also dose-dependently blocked by prior administration with Rp-8-p-CPT-cGMPS. Rp-8-p-CPT-cGMPS given at 15 and 30 μg dramatically suppressed the NMDA-induced decrease of the tail-flick latency by 13.3% ( FIG. 3 , p<0.01) and 20.7% ( FIG. 3 , p<0.01), respectively. Rp-8-p-CPT-cGMPS at 7.5 μg failed to produce significant effect on the NMDA-evoked facilitation of the tail-flick reflex ( FIG. 3 , p>0.05).
Subjective observation of rats injected with Rp-8-p-CPT-cGMPS, NOC-12, Rp-8-p-CPT-cGMPS+NOC-12, Rp-8-p-CPT-cGMPS+NMDA and MK-801+NMDA revealed no obvious changes in animal behavior during a period of 2 h when compared with control animals, Although intrathecal administration of NMDA to some rats produced a caudally directed biting and scratching behaviors. No sedative or toxic effect was observed after intrathecal administration of any of the agents used in this study.
Animal models used in these studies correlate well with humans, including nociception and anesthetic thresholds.
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Several lines of evidence have shown a role for the nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) signaling pathway in the development of spinal hyperalgesia. However, the roles of effectors for cGMP are not fully understood in the processing of pain in the spinal cord. cGMP-dependent protein kinase (PKG) Iα but not PKGIβ was localized in the neuronal bodies and processes, and was distributed primarily in the superficial laminae of the spinal cord. Intrathecal administration of an inhibitor of PKGIα, Rp-8-[(4-Chlorophenyl)thio]-cGMPS triethylamine, produces significant antinociception. Moreover, PKGIα protein expression was dramatically increased in the lumbar spinal cord after noxious stimulation. This upregulation of PKGIα expression was completely blocked not only by a neuronal NO synthase inhibitor, and a soluble guanylate cyclase inhibitor, but also by an N-methyl-D-aspartate (NMDA) receptor antagonist, MK-801. Noxious stimulation not only initially activates but also later upregulates PKGIα expression in the superficial laminae via an NMDA-NO-cGMP signaling pathway, suggesting that PKGIα plays an important role in the central mechanism of inflammatory hyperalgesia in the spinal cord.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application is a continuation of application Ser. No. 09/651,392, filed Aug. 29, 2000, now U.S. Pat. No. 6,284,417, issued Sep. 4, 2001, which is a continuation of application Ser. No. 09/310,521, filed May 12, 1999, now U.S. Pat. No. 6,165,650, issued Dec. 26, 2000, which is a divisional of application Ser. No. 08/921,656, filed Aug. 28, 1997, now U.S. Pat. No. 5,938,860, issued Aug. 17, 1999.
BACKGROUND OF THE INVENTION
This invention relates to integrated circuit fabrication tools and processes and, more particularly, to a method and apparatus for cleaning a pellicled reticle.
Integrated circuits (IC) commonly are fabricated on a semiconductor wafer. The semiconductor wafer typically is subjected to doping, deposition, etching, planarizing and lithographic processes to form semiconductor devices in the wafer. The wafer typically is cut to form multiple semiconductor “IC chips”. Each chip includes many semiconductor devices. Although the label semiconductor is used, the devices are fabricated from various materials, including electrical conductors (e.g., aluminum, tungsten), electrical semiconductors (e.g., silicon) and electrical non-conductors (e.g., silicon dioxide).
A reticle is used in a lithographic process to define a photomask. A lithographic process refers to a process in which a pattern is delineated in a layer of material (e.g., photoresist) sensitive to photons, electrons or ions. The principle is similar to that of a photocamera in which an object is imaged on a photo-sensitive emulsion film. While with a photo-camera the “final product” is the printed image, the image in the semiconductor process context typically is an intermediate pattern, which defines regions where material is deposited or removed. The lithographic process typically involves multiple exposing and developing steps, wherein at a given step the photoresist is exposed to photons, electrons or ions, then developed to remove one of either the exposed or unexposed portions of photoresist. Complex patterns typically require multiple exposure and development steps.
A typical lithographic system includes a light source, optical system and transparent photomask. The light source emits light through the optical system and photomask onto a photoresist layer of a semiconductor wafer. The photomask defines the “intermediate pattern” used for determining where photoresist is to be removed or left in place. Conventional photomasks are transparent masks. A photomask typically is formed on a glass blank. The mask and blank together are referred to as a reticle. Conventional materials for the blank include soda lime, borosilicate glass or fused silica. The photomask is formed by a film of opaque material. Typically, the film is formed with chrome less than 100 nm thick and covered with an anti-reflective coating, such as chrome oxide. The purpose of the anti-reflective coating is to suppress ghost images from the light reflected by the opaque material.
The photomask serves to define geometries for materials deposited or etched on the wafer or materials applied to the wafer. The patterned film on the reticle blank includes mask lines and line spacings of less than 10 microns. Depending on the reduction factor x, line width and line space geometries for a resulting semiconductor device are from less than 10 microns to less than 2 microns. Other mask line spacings and semiconductor line spacings also can be achieved. When working with such small geometries, it is important that the reticle and other components in the fabrication processes be free of foreign particles. A tiny speck of dust alters the desired pattern to be imaged onto the wafer. Conventionally, a thin transparent membrane, referred to as a pellicle membrane, is applied over the photomask portion of the reticle to keep the photomask portion free of foreign particles. The pellicle membrane typically is positioned at a height above the photomask. Such height is greater than the focal length of the light imaged onto the photomask. Thus, small particles on the pellicle membrane will not block light from reaching the photomask.
Another problem caused by foreign particles is bad registration of the reticle. During a lithographic process, the reticle rests on a reticle table. The reticle table typically is part of a stepper device, which also includes a light source and a stepper control. The stepper control manages the relative position of the light source and the reticle table. Even the smallest of particles on the edge of the reticle can lift a portion of the reticle off the reticle table. Such offset of the reticle can result in bad registration of the light onto the wafer, which, in turn, can result in bad overlay from one pattern to another. Because the pellicle membrane typically is very fragile, the pellicle membrane is destroyed during the course of cleaning the reticle. Conventionally, the pellicle membrane is removed, the entire surface of the reticle is cleaned, and then the reticle undergoes requalification. Such a process is very time consuming and costly. Accordingly, there is a need for an alternative method and apparatus for cleaning a reticle.
BRIEF SUMMARY OF THE INVENTION
According to the invention, a reticle having a pellicle is cleaned without removing or damaging the pellicle. The pellicle includes a pellicle membrane and a pellicle frame. A cover encases the pellicle, sealing it from the external environment during the cleaning process.
According to one aspect of the invention, the cover fits around the periphery of the pellicle frame and covers the pellicle membrane. An edge of the cover in contact with the reticle (adjacent the pellicle frame) forms a seal. In a preferred embodiment, the edge includes a groove within which is an O-ring seal.
According to another aspect of the invention, the reticle is fastened to reticle supports on a spin chuck during the cleaning process. An anchor plate presses the cover to the reticle, maintaining the pellicle sealed from the external environment. The anchor plate fastens to the spin chuck. Thus, the cover and reticle are sandwiched together between the anchor plate and spin chuck.
According to another aspect of the invention, a system for cleaning a reticle having a pellicle frame and pellicle membrane is provided. The reticle has a pattern formed on a first surface, the pattern occurring within a first area of the first surface. The pellicle frame is attached to the first surface, defining a border of the pattern. The pellicle membrane is attached to the pellicle frame and elevated above the pattern, the pellicle membrane sealing the first area. The reticle is secured to a support. A lid encases the pellicle frame and pellicle membrane. The lid has a first surface in contact with the first surface of the reticle. A clamp pushes the lid to the reticle.
According to another aspect of the invention, the lid has a first surface in contact with the first surface of the reticle. The lid has a groove formed within the lid's first surface. An O-ring seal is within the groove. The O-ring seal is pressed into contact with the reticle by the lid under a force of the clamp. The clamp is secured to the support.
According to another aspect of the invention, a fluid under pressure is ejected onto the reticle, wherein the pellicle membrane is shielded from the fluid by the lid. A drive mechanism rotates the support, altering a portion of the reticle receiving the fluid under pressure.
According to another aspect of the invention, the lid and reticle serve as an apparatus for encasing the pellicle. The lid has a recessed area, which is bordered peripherally by a first wall. The first wall is adjacent to a first edge. The first edge has a seal extending around a peripheral border of the recessed area. The first wall has a height greater than a height of the pellicle frame. The lid encases the pellicle membrane and pellicle frame within the recessed area with the seal making contact with the reticle on the first surface.
According to another aspect of the invention, the seal is an O-ring seal within a groove along the first edge for sealing the recessed area of the lid and the enclosed pellicle frame and pellicle membrane from an environment of the reticle.
According to another aspect of the invention, a method for cleaning a reticle without damaging or removing a pellicle membrane is performed. At one step, the pellicle is covered with a lid to separate the pellicle from an external environment of an uncovered portion of the reticle. At another step, a force is applied to the lid to seal the pellicle from the external environment. At another step, the reticle is secured to a base. At another step, fluid under pressure is ejected onto the uncovered portion of the reticle to clean the uncovered portion of foreign particles.
An advantage of the invention is that a reticle, which does not accurately rest on a stepper table due to foreign particles, is cleaned without removing or damaging the pellicle. An effect of this advantage is that the reticle does not need to go through an extensive process of reapplying a pellicle frame and pellicle membrane and requalifying the reticle for use in a lithographic process. These and other aspects and advantages of the invention will be better understood by reference to the following detailed description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 is a block diagram of a conventional lithographic system with photomask and wafer;
FIG. 2 is a perspective view of a conventional reticle with pellicle frame and pellicle membrane;
FIG. 3 is a side view of the reticle, pellicle frame and pellicle membrane of FIG. 2;
FIG. 4 is a diagram of a reticle cleaning system according to an embodiment of this invention;
FIG. 5 is a plan view of a spin chuck of FIG. 4 according to an embodiment of this invention;
FIG. 6 is a plan view of a pellicle cover of FIG. 4 according to an embodiment of this invention;
FIG. 7 is a side view of the pellicle cover of FIG. 6, along with a side view of an O-ring; and
FIG. 8 is a perspective view of an anchor cap of FIG. 4 according to an embodiment of this invention.
DETAILED DESCRIPTION OF THE INVENTION
Overview
FIG. 1 shows a block diagram of a conventional lithographic system 10 . The lithographic system 10 includes a light source 12 which emits light 13 (e.g., ultraviolet light, visible light, infrared light). The light passes through a mask formed on a reticle 14 , then through an opening in a reticle table 16 , and onto a semiconductor wafer 18 . A stepper controller 20 (also known as an aligner) controls the relative positioning of the light source 12 and reticle table 16 . Typically, the light 13 serves to develop portions of photoresist applied to the semiconductor wafer 18 . The mask defines a pattern distinguishing which portions of the photoresist are developed and which are not developed.
FIGS. 2 and 3 show a reticle 14 . The reticle includes a transparent plate 22 or “blank” covered with a patterned film 24 of opaque material (i.e., the photomask). Although the size may vary, an exemplary reticle 14 is 6 inches by 6 inches and 0.25 inches thick. Conventional materials for the blank include soda lime, borosilicate glass or fused silica. The film of opaque material typically is a film of chrome less than 100 nm thick and covered with an anti-reflective coating such as chrome oxide. Within an area 26 , the film 24 defines masks 28 for respective portions of the semiconductor wafer 18 . For example, in one embodiment illustrated, fifteen masks are shown. Each mask 28 within the area 26 may be the same or different, so as to make the same or different integrated circuits.
Attached to the reticle is a pellicle frame 30 . In an exemplary embodiment, the pellicle frame 30 is adhered to the reticle 14 by double back tape. Other adhesives structures may be used, however. The pellicle frame 30 encloses the area 26 of the reticle having the masks 28 . Adhered to the pellicle frame 30 is a thin membrane, referred to as a pellicle membrane 32 (FIG. 3 ). The pellicle membrane seals the area 26 from the external environment. As described in the background section, it is desirable to avoid foreign particles on a photomask. When a reticle with masks 28 is formed, the surface is cleaned and qualified to assure that the mask is accurate and that no foreign particles are present. As part of such a qualification process, the pellicle membrane 32 is adhered to the pellicle frame 30 . The pellicle membrane 32 protects the masks 28 from foreign particles. The pellicle membrane is formed of a conventional material, such as cellulose acetate or nitrous cellulose.
As shown in FIG. 1, the reticle 14 rests on a reticle table 16 during the lithographic process. The lithographic processes often require that a given reticle 14 be replaced from the reticle table 16 with another reticle having a different mask pattern. This movement of reticles on and off the reticle table 16 can cause microscopic particles to adhere to the reticle 14 . Further, reticles typically are stored in a carrying case. Microscopic particles also may adhere to the reticle from rubbing along rails of the reticle carrying case. If there are any foreign particles on the reticle in the regions 33 (see FIG. 2) where the reticle 14 is supposed to contact the reticle table 16 , then the reticle may not be seated exactly. A portion of the reticle may be higher than another portion. This can result in bad registration of the light passing through a mask 28 onto a wafer, or in bad overlay from one mask to another mask. If such a problem is detected, the reticle is removed and cleaned. Because the pellicle membrane 32 typically is very fragile, the pellicle membrane is destroyed during the course of cleaning the reticle. Conventionally, the pellicle is removed and the entire surface of the reticle is cleaned. The pellicle frame and a pellicle membrane then are reapplied, and the structures 14 , 30 , 32 requalified for the desired lithographic operations.
FIG. 4 shows a cleaning system 40 , according to an embodiment of this invention. During cleaning, the pellicle membrane 32 and pellicle frame 30 are covered to avoid damage. A lid 42 encases the pellicle membrane 32 and pellicle frame 30 , sealing the pellicle from the external environment of the cleaning system. In one embodiment, an O-ring 44 defines the seal between the lid 42 and the reticle 14 adjacent to the pellicle frame 30 . The O-ring 44 or seal is formed from silicon or another material.
During a cleaning operation, the reticle 14 is secured to a spin chuck 46 . The spin chuck 46 includes reticle supports 48 . The reticle 14 rests on the reticle supports 48 . An anchor plate 50 resides on top of the lid 42 . The anchor plate 50 is bolted to the spin chuck 46 , pressing the lid 42 to the reticle 14 to maintain the seal, and pressing the reticle to the reticle supports 48 . Thus, the reticle 14 and lid 42 are sandwiched between the anchor plate 50 and spin chuck 46 .
With the lid 42 and reticle 14 secure, a rotary drive 52 rotates the spin chuck 46 . In addition, a spray source 54 ejects a fluid to clean and rinse the reticle 14 . In one embodiment, de-ionized water or another fluid is ejected as a fan spray 57 to the upper surface of the anchor plate 50 , reticle 14 and spin chuck 46 assembly and as a rinse spray 59 to a lower surface of such assembly. Then a fluid under pressure (e.g., 500 psi) is ejected as a high pressure spray 56 onto at least the exposed portions of the reticle 14 to clean away any foreign particles on the reticle 14 . The fluid ejected from the fan spray 57 and rinse spray 59 is de-ionized water in one embodiment, although other liquid or gas fluids may be used. The fluid ejected from the high pressure spray 56 is ammonium hydroxide, de-ionized water and/or another liquid or gas fluid. In one method for cleaning the reticle, the spin chuck 46 rotates at 1500 revolutions per minute during the ejection of the fluids. The high pressure spray 56 then ceases, followed by cessation of the fan spray 57 and rinse spray 59 . The spin chuck 46 then increases the rotational rate (e.g., to 2000 rpm) during a drying time period. The speeds of revolution, the pressure of the fluids emitted from sprays 56 , 57 and 59 and the time for spraying and drying the assembly may vary.
The reticle 14 , being secured to the spin chuck 46 , rotates with the spin chuck 46 . Rotation of the reticle 14 places different exposed portions of the reticle 14 in the path of the high pressure fluid spray 56 . In a preferred embodiment, the portion of the reticle 14 which is in contact with the reticle table 16 during a lithographic process is exposed during the cleaning process. Specifically, such portion is not covered by the lid 42 .
FIG. 5 shows a spin chuck 46 according to an embodiment of this invention. The spin chuck 46 serves as a base to which the other components are secured. The base 46 , either with or without the reticle supports 48 , serves as a support for the reticle 14 (e.g., in one embodiment supports are integral to the base). In one embodiment, the spin chuck 46 is of sufficient area that a portion of the spin chuck 46 is exposed when the reticle 14 is secured to the spin chuck. Openings 58 occur in the exposed areas along opposite edges 60 , 62 of the reticle 14 . Such openings receive pins 64 (see FIG. 8 ), which secure the anchor plate 50 to the spin chuck 46 .
In various embodiments, the spin chuck 46 has different shapes (e.g., circular, square, rectangular, or other shape). In the embodiment illustrated, the spin chuck is a ring 66 with spokes 68 extending from a central portion 70 . Multiple reticle supports 48 are attached to the spin chuck 46 . In one embodiment, the reticle supports 48 are bolted to the spin chuck 46 . In another embodiment, the reticle supports 48 are integral to the rest of the spin chuck 46 . Each reticle support has a distal surface or pin 72 upon which the reticle 14 rests during cleaning. The spin chuck 46 is rotated by the rotary drive 52 .
FIGS. 6 and 7 show the lid 42 for covering the pellicle frame 30 and pellicle membrane 32 . The lid is generally planar, defining two faces 73 , 76 . One face 76 defines a generally planar exterior surface. The contour of the exterior surface 76 , however, need not be planar and may vary. The other face 73 defines a distal surface 80 and a recessed area 74 . The recessed area is delimited by an interior surface 82 and a wall 84 and a distal surface 80 . The wall 84 extends from the interior surface 82 to the distal surface 80 . When the lid 42 is applied over the pellicle onto the reticle 14 , the pellicle frame 30 and pellicle membrane 32 are enclosed within the recessed area 74 . Accordingly, the height of the wall 84 relative to the interior surface 82 is greater than a height of the pellicle frame 30 . The lid 42 includes a seal along the distal surface 80 . In one embodiment, the seal is formed by a groove 86 and an O-ring 44 . In an exemplary embodiment, the groove is 0.07 inches wide with a depth of 0.04 inches. The distal surface 80 spans a width of 0.2 inches. Such dimensions, however, vary for differing embodiments. The O-ring 44 seats within the groove 86 and extends along the entire circumference of the distal wall 80 so as to form a seal all the way around the pellicle frame 30 . In other embodiments, an alternative sealing device is used, such as a gasket. Preferably, the seal and lid 42 are formed of material which does not readily chip. The advantage of such material is the avoidance of leaving foreign particles on the reticle 14 when the lid 42 is removed from the reticle 14 . When the lid 42 is applied to the reticle 14 , the pellicle frame 30 and pellicle membrane 32 are completely encased between the lid 42 and reticle 14 . When the lid 42 is pressed to the reticle 14 , the seal isolates the pellicle membrane 32 from the environment of the cleaning system 40 , and, in particular, from the ejected fluid. As the ejected fluid would break the pellicle membrane 32 , the lid 42 prevents the pellicle membrane 32 from being damaged during the cleaning process.
FIG. 8 shows the anchor plate 50 , which clamps the lid 42 to the reticle 14 and holds the reticle 14 to the spin chuck 46 . The anchor plate 50 includes a recessed area 90 bordered by two opposing walls 92 , 94 . In the embodiment illustrated, the recessed area 90 is not enclosed. The anchor plate 50 fits over the lid 42 with the lid 42 fitting between the walls 92 , 94 of the recessed area 90 . In one embodiment, the lid 42 is mounted to the anchor plate 50 with screws. The walls 92 , 94 fix the orientation of the lid 42 relative to the reticle 14 , so as to prevent movement, displacement or offset of the lid 42 by the ejected fluid during cleaning. The anchor plate 50 defines openings 96 which receive the pins 64 . The pins 64 pass through the openings 58 in the spin chuck 46 (see FIG. 5 ). In one embodiment, a respective screw 65 extends into a threaded opening of each pin 64 . The screw 65 pushes the anchor plate 50 toward the spin chuck 46 . In alternative embodiments, the pins are integral to either the anchor plate 50 or spin chuck 46 . In another embodiment, an alternative clamp (e.g., C-clamp; nut and bolt) is used to secure the anchor plate 50 to the spin chuck 46 .
Meritorious and Advantageous Effects
An advantage of the invention is that a reticle which does not accurately rest on a stepper table due to foreign particles is cleaned without removing or damaging the pellicle membrane. An effect of this advantage is that the reticle does not need to go through an extensive process of re-applying a pellicle frame and pellicle membrane and requalifying the reticle for use in a lithographic process. Although a preferred embodiment of the invention has been illustrated and described, various alternatives, modifications and equivalents may be used. Therefore, the foregoing description should not be taken as limiting the scope of the invention which is defined by the appended claims.
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A reticle having a pellicle frame and pellicle membrane is cleaned without removing or damaging the pellicle membrane. A cover encases the pellicle membrane and pellicle frame, sealing the pellicle from the external environment during a cleaning process. The cover fits around the periphery of the pellicle frame and covers the pellicle membrane. An edge of the cover in contact with the reticle forms a seal. The reticle is fastened to reticle supports on a spin chuck during the cleaning process. An anchor plate presses the cover to the reticle, maintaining the pellicle sealed from the external environment. The cover and reticle are sandwiched together between the anchor plate and spin chuck.
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This application claims benefit of provisional application 60/073,098, filed Jan. 30, 1998.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to orthopedic devices and in particular ankle braces and more particularly to ankle braces which allow flexing of the ankle forward and backward, plantar-flexion and dorsiflexion, while preventing the ankle from flexing inward or outward, inversion or eversion, in order to promote healing of an injured ankle or prevent injury to an injury prone ankle during exercise. Particularly, the present invention relates to orthopedic devices and ankle braces which have a removable or detachable single piece hinge.
2. Discussion of the Prior Art
Ankle injuries are among the most common injuries in sports. In order to protect the ankle, many athletes have wrapped the ankle area with adhesive tape. The application of tape is expensive both because it is time consuming and because of the tape itself. It is also not very effective because the tape loosens quickly after exercise has begun. The use of exercise tape has also been shown to weaken ankles if used over a long period of time because it causes a loss of plantarflexion and dorsiflexion.
When an ankle is injured, the traditional method for promoting healing is to apply pressure to the area to reduce swelling and to prevent lateral movement of the ankle. The method of applying pressure to the ankle limits the range of motion over the ankle. When large areas are covered by a compression device, the material in contact with the foot must be fairly flexible or soft, such as an elastic bandage or an air bag, in order to avoid discomfort to the wearer and provide the amount of flexibility and movement required for athletic flexing of the ankle joint. This severely limits the amount of pressure that can be applied to the injury site in order to reduce the swelling caused by the ankle injury. An additional drawback found when air bag type devices are utilized is that the ankle and foot directly contact the bag in order to move, causing irritation of the skin. This irritation may be caused from the friction incurred by such contact which, in turn generates heat is which is not desirable to add to a swollen area of the body.
Another treatment method is to exercise the joint to promote healing. Exercise brings greater blood flow to the area and prevents the atrophy of the muscles involved. The current trend in medicine is to promote exercise as soon as possible. However, in traditional treatment methods, the ankle could not be properly exercised until after the compression device was removed thereby greatly delaying the exercise therapy. It is therefore desirable to provide an orthopedic device which allows exercise of the injury site while additionally resisting mobility in the direction which would irritate the injury.
As indicated, one method to promote healing of the ankle is preventing lateral movement of the ankle thereby allowing forward and backward flexing but preventing inward and outward flexing. The wearing of an ankle brace provides such protection while preventing inflammation of the injured ankle areas. Visually this forward and backward flexing is based upon a brace which is hinged in such a way to pivot backwards and forwards.
Most prior art devices that provide for pivoting of the ankle in addition to providing lateral support thereof are connected at the pivot point by an undetachable hinge or rivet. This type of non-detachable but pivotable connection between the stirrup and the pivot legs proves burdensome in both manufacturing and wearability issues. During manufacturing, when a rivet or other metal pivoting joint needs to be applied, a secondary assembly and additional attachment steps is required to inner-connect the separate portions of the ankle brace. Additionally, from the wearer's perspective, these types if pivoting joints add bulk and weight to the ankle brace.
SUMMARY OF THE INVENTION
The present invention provides an ankle brace which pivots along the same axis as the ankle and which has an easily separable, non-permanent single piece pivoting hinge.
The ankle brace of the present invention incorporates an ankle brace having a stirrup which is pivotally connected to an inner and outer pivot leg in combination with an adjustable strap positioning fastener for protecting and exercising an injured ankle. The hinge connection between the inner and outer legs of the stirrup and the inner and outer pivot legs is a single piece hinge minimizing the content of the overall brace and simplifying the overall construction of the ankle brace. The adjustable strap positioning means acts to firmly attach the pivoting legs of the ankle brace to the wearer. On the interior of the inner and outer pivot leg is attached softening pads which are secured to said pivot legs by VELCRO or other attachment means.
It is therefore an object of the present invention to overcome the deficiencies outlined above. It is a further object of the present invention to remove the assembly step traditionally required for pivoting ankle braces wherein a metal rivet or other permanent pivoting joint is required. It is a further object of the present invention to remove the hardware and extra weight present in prior art ankle braces.
More particularly, the present invention includes an ankle brace to be worn by a wearer to prevent ankle injury or encourage healing of an injured ankle, including a heel stirrup having a flat base portion and an inner and outer upright leg, inner and outer pivot legs which are pivotally attached to the inner and outer legs along inner and outer pivot points respectively.
Another object of the present invention is to provide axial movement of the ankle while additionally providing lateral support in order to prevent inversion or eversion of the ankle. It is a further object of the present invention to provide the greatest possible flexing of the ankle forward and backwards while keeping the pivot point of the ankle brace detachable yet providing significant lateral support and protection.
Another object of the present invention is to provide an ankle brace which allows flexing of the ankle forward and backwards, while also providing interchangeable parts for the stirrup portion of the brace and the individual pivot leg members.
The use of the ankle brace of the present invention provides the optimum combination of pressure applied to the injured area to reduce swelling and flexibility of the joint to permit exercise which promotes healing and reduces muscle atrophy. In this way a single brace provides the benefits both of a compression strategy and an exercise strategy to promote healing while protecting the ankle from further injury.
The present invention provides an ankle brace which meets all of the objectives outlined above. The present invention has a stirrup portion which is pivotally connected to inner and outer pivot legs, said pivot legs having on the interior thereof softening pads for compression directly against the wearer's leg or ankle. Additionally, a connecting strap is provided for tightening the inner and outer pivot legs in combination with the softening pads directly against the leg is while also providing a unique single piece pivoting or attachment hinge which allows for a maximum forward and backward flexing while also providing significant lateral support for the ankle. The single piece hinge of the present invention does not utilize rivets or other metallic hinge means which are commonly found in prior art braces. The hinge of the present invention utilizes a pivot button located on a flexing tab which is inserted into a thickened head portion of each upright leg of the stirrup. The stirrup and pivot legs of the ankle brace described herein are fully detachable from each other yet provide for a simple and rotatable attachment means which will not become easily detached through athletic activity.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view taken from the front left side of an ankle brace made in accordance with the present invention;
FIG. 2 is an exploded perspective view of the ankle brace of FIG. 1;
FIG. 3 is a close-up partial cutaway view of the removable hinge of the ankle brace shown in FIG. 1;
FIG. 3A is a close-up partial cutaway view of an alternative embodiment hinge of the present invention wherein the removable hinge of the ankle brace shown in FIG. 3 does not have a compression channel or a deformable tongue containing the pivot button;
FIG. 4 is a perspective view taken from the front left side of an alternative embodiment of an ankle brace made in accordance with the present invention;
FIG. 5 is an exploded perspective view of an ankle brace of FIG. 4; and
FIG. 6 is a close-up of the alternative embodiment hinge for the ankle brace shown in FIG. 4.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The ankle brace 10 of the present invention is shown in FIG. 1. In this figure, the stirrup 20 of the ankle brace is shown as being comprised of a flat base portion 21, an inner upright leg 22 and an outer upright leg 23. Pivotally attached to the inner and outer upright legs 22 and 23 of stirrup 20 are outer pivot leg 40 and inner pivot leg 41. Such rotatable connection to the stirrup 20 allows the inner and outer pivot legs 40 and 41 to move forward and backwards rotating about pivot point 25 while additionally providing lateral support through upright legs 22 and 23. Attached to the interior of the inner and outer pivot legs 40 and 41 are inner and outer softening pads 47 and 48 which contact directly against the wearer's leg. Wrapped around the exterior of the inner and outer pivot legs 40 and 41 is the connecting strap 45 which enables the ankle brace 10 to be securely tightened around the wearer's leg. The inner and outer pivot legs 40 and 41 are easily detachable from stirrup 20 while at the same time they provide strong lateral support to the ankle through legs 22 and 23.
The stirrup 20 of the present invention is substantially a "U" shape and is comprised of the flat bottom portion 21 and the inner and outer upright legs 22 and 23. Both inner and outer upright legs 22 and 23 extend substantially vertically from the flat base portion 21. The stirrup 20 may be comprised of a strong thermoplastic material strong enough to prevent lateral shifting of the ankle retained between the inner and outer upright legs 22 and 23. The upright legs 22 and 23 may also be slightly offset to compensate for the typical slight outward pronation of the wearer's ankle.
Shown more closely in FIG. 3 is the hinged or pivoting means 70 of the present invention wherein the thickened head portion 26 of outer upright leg 23 is shown in cross section. An ovalized channel 27 is centrally cut into the interior of the thickened ovalized head portion 26 of upright legs 22 and 23. The ovalized channel 27 formed in the head portion 26 creates inner and outer support post 29 and 28 respectfully. Channel 27 is of sufficient width to receive flange portion 43 is of the outer pivot leg 40. Ovalized flange 43 is formed on the bottom distal edge of each of said inner and outer pivot legs and each is inserted into channel 27 between inner and outer support posts 29 and 28 so that pivot button 42 fits within pivot point aperture 25 and rotates therein. Pivot button 42 of outer pivot leg 40 rests upon the outer periphery of flexing tab 55. Flexing tab 55 is formed from an inverted U-shaped cutaway section out of said ovalized head of flange 43. Deformable tongue or flexing tab 55 deflects backwards sufficiently so that pivot button 42 slides in between outer and inner support posts 28 and 29 causing flexing tab 55 to depress into elongated recess 24. Elongated U-shaped recess 24 is sufficiently deep enough such that tab 55 may be depressed sufficiently that pivot button 42 easily slides against outer support post 28 and reflexes into position after full insertion of the flange 43 into channel 27 such that pivot button 42 extends through pivot point aperture 25 of outer upright leg 23.
Alternatively, as shown in FIG. 3A, a simpler embodiment is disclosed wherein the flexing tab 55 is removed from the overall design. In this embodiment, inner and outer support posts 28 and 29 which form the ovalized channel 27 receiving the flange portion 43 of the pivot leg 40 deform sufficiently enough that a flexing tab is not required for insertion of the pivot button 42 into aperture 25. As the material which the pivoting means 70 is comprised of consists of a resilient but slightly deformable thermoplastic material, assembly of the hinge is easily completed without the need for the flexing tab or compression channel. In all of the designs, significantly the pivoting means 70 is comprised of a single piece hinge made of unitary construction, single piece in that the comprised hinge does not require in the introduction of a secondary rivet or attachment means, as is required in the prior art. Thus, assembly of the ankle brace is marked by a reduction in manufacturing steps and parts. Further, the designed unitary or single piece hinge is sufficiently stable to provide for lateral support and movement of the ankle once the brace is in place around the users ankle.
As can be seen in FIG. 3, flange 43 of outer pivot leg 40 is rounded at the bottom most portion which matches the curvature of channel 27 formed in thickened head portion 26 of the outer upright leg 23. This matching curvature of the flange 43 and channel 27 allows the inner and outer pivot legs 40 and 41 to rotate along a wide range while also providing vertical support of the outer pivot leg by the outer upright leg 23. It is preferred that the rounded flange portion of the outer pivot leg not directly contact the bottom most portion of the channel 27. Additionally, the elongated recess 24 formed in the support post of the thickened head portion 26 is ramped so that the deepest portion of the recess is formed at the top of the inner support post 29 while, closer to the pivot point aperture 25, the recess has less depth. This ramp design of the elongated recess forces flexing tab 55 and pivot button 42 outward as the flange 43 is inserted farther into channel 27. However, the depth at the bottom most portion directly adjacent to the pivot point aperture 25 must be sufficiently deep enough to allow the pivot point button 42 to be pushed inwards so that the flange 43 may be removed from the channel 27.
A benefit of this pivot means 70 as noted is that it provides substantial lateral support of the ankle while also preventing the inadvertent removal of the flange 43 from the channel 27 during athletic activity. The design as shown in the figures does not require the additional assembly step noted in the prior art wherein metal rivets are utilized to connect the upright legs of the stirrup 20 with the outer and inner pivot legs 40 and 41. This manufacturing and assembly of the ankle brace 10, and particularly of the pivot means 70 of the present invention, is substantially easier. Further, the added bulk of having a metal joint is further moved. Finally, the interchangeability of the stirrup 20 and the pivot legs 40 and 41 adds to the ease of repair and replacement of portions of the brace 10. Thus, if a wearer requires varying size portions for the flat base portion 21 and pivot leg portions 40 and 41, an entire new brace assembly need not be built.
Turning to FIG. 2, an exploded view of the ankle brace 10 of the present invention is shown wherein the inner and outer softening pads 47 and 48 are detached from the outer and inner pivot legs 40 and 41. Softening pad 47 has attached thereon loop connector pad material 44 which is of a hook and loop type fastening means such as VELCRO and the like. Matching hook connector material 49 is placed on the interior side of the outer pivot leg 40 and is shown in phantom. Matching hook connector material 49 is placed on the interior portion of inner pivot leg 41. The hook connector material 49 placed on the interior of the pivot legs mates with loop connector pad material 44 which is located on the exterior surface of softening pad 47 and 48. Softening pad 47 and 48 as indicated, directly contact the wearer's leg and is made of a soft pliable material such as EVA or other similar type material.
Compressing the outer pivot leg 40 and inner pivot leg 41 as well as softening pads 47 and 48 against the legs is connecting strap 45 which is made of a nylon material and which circumscribes the wearer's leg and the pivot legs 41 and 40. Cuff loop 52 located at one end of the connecting strap 45 attaches into mating edge surface 53 of the inner pivot leg 41. Connecting strap 45 circumscribes the pivot legs and softening pads to compress them against the wearer's leg. Additional loop type material 54 may be placed on the exterior surface of outer pivot leg 40 so that connecting strap 45 can securely attach thereto. Securing strap 45 will additionally have loop connecting material formed on the interior surface thereof generally at the mid point for attaching to the loop type material 54 on pivot leg 40. Hook connector material 51 located at the opposite end of connecting strap 45 as compared to the cuff loop 52 fully wraps around the wearer's leg and reattaches to exposed loop material on the outer surface of the connecting strap, not shown, in order to provide a secure compression attachment around the leg.
As can be seen in FIG. 2, unitary hinge or pivot means 70 is comprised of pivot legs 40 and 41 and can swivel about the pivot axis point 25 while providing lateral support by the inner and outer upright legs 22 and 23. The ankle brace of the present invention restrains against inversion and eversion of the ankle while allowing plantarflexion and dorsiflexion.
Base portion 21, while shown in FIG. 2 as being substantially oval in shape, may in fact be contoured so that it matches the shape of the mid-section of the foot. The hinge means 70 provided for herein is also significant in that the position of the hinges is such that they are in line with the ankle bones (malleoli) of the wearer as the medial malleoli is superior to the lateral malleoli.
Shown in FIG. 4 is an alternative embodiment of the ankle brace 100. The hinge 110 of the ankle brace 100 as opposed to pivoting around a pivot button 42 swivels within a channel 116 shown in FIG. 7. Outer upright leg 123 has a thickened head portion 115 within which channel 116 is formed. As can be seen from the drawing, channel 116 has a narrowed ridge portion 111 and a widened area 112. The narrow ridge portion 111 retains the pivot leg 140 within channel 116. Pivot leg 140, as is shown in FIG. 7, has grooved flange 113 at its distal end. The groove 119 formed in flange 113 receives the narrow ridge portion 111 of channel 116. This channel and flange combination allows the pivot leg 140 to swivel within channel 116 forwards and backwards allowing axial flexing of the ankle. However, inner and outer upright legs 122 and 123 provide lateral support for the ankle preventing re-injury thereof. The flange and channel hinge design shown in FIG. 7 provides for smooth movement of the pivot leg 140 within channel 116. As is shown in FIG. 6, the overall design of the ankle brace 100 is similar to the previous design except for the hinge itself. Stirrup 120, base portion 121 and inner and outer upright legs 122 and 123 are made of a stiff or rigid material providing adequate lateral support of the ankle. Forward flexing of the leg and the ankle is provided for by the channel 116 and flange 113 hinge design. Attachment to the wearer's leg is similarly provided for by an attachment strap 134 which has standard hook and loop type attachments for securing the pivot legs 140 and 141 to the wearer's leg.
The foregoing detailed description is given primarily for clearness of understanding and no unnecessary limitations are to be understood therefrom for modifications will become obvious to those skilled in the art upon reading this disclosure and may be made without departing from the spirit of the invention or the scope of the appended claims.
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An ankle brace with a single piece hinge, interchangeable stirrup and pivot legs and an adjustable strap position fastener for protecting and exercising an injured ankle or for use with other orthopedic devices is described herein. The ankle brace pivots around a singular pivoting point on both the interior and the exterior portion of the lateral support members of the stirrup portion of the brace. The pivoting hinge of the ankle brace does not require use of metal rivets or bulky hinges and may be easily connected together by the wearer or manufacturer. The separable hinge design of the ankle brace described herein is sufficiently strong to provide substantial lateral support while allowing for forward and backward flexing of the ankle. The design also allows for interchanging the stirrup portion of the brace with different inner and outer pivot legs.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the field of data processing systems. More particularly, this invention relates to the field of controlling use of a computer program with a licence key.
2. Description of the Prior Art
It is known to provide computer programs that when they are installed require the user to enter licence key data which is validated with a predetermined metric before use of the computer program is allowed. The licence key data may be supplied together with the media upon which the computer program was supplied. Alternatively, a user may contact the computer program provider, such as via the internet, to register the product and obtain a licence key at that time.
Whilst the above may be effective preventing unlicensed use, a problem exists in respect of existing installed software without such use control mechanisms. The loss of revenue resulting from the unlicensed use of such existing software is highly significant.
SUMMARY OF THE INVENTION
Viewed from one aspect the present invention provides a computer program product for controlling use of a computer program installed on a computer, said computer program product comprising:
a product update for installation at said computer; wherein said product update serves to add a licensing control mechanism to said computer program installed on said computer, said licensing control mechanism being responsive to license key data to indicate that said computer program is licensed.
The invention recognises that it is becoming increasingly common and accepted that a user will regularly apply product updates to an installed computer program. These product updates are provided for a variety of different reasons, such as to fix newly discovered bugs or cure security vulnerabilities in installed computer programs. This product update route may be used to retrospectively add licensing control mechanisms to an already installed computer program. A user is motivated to apply a product update in order to benefit from the bug fixes and the like provided by that product update and at the same time the computer program provider may benefit from the ability to add a licensing control mechanism to existing installed copies of a computer program which do not have such a mechanism.
This technique is particularly advantageous when the computer program and product updates are of a nature where the product updates will normally be regularly applied by a user in order to maintain the continued effective provision of existing functionality of a computer program. One example of such a combination would be a payroll computer program in which periodic product updates are provided and need to be applied in order to take account of changes in the surrounding tax provisions and other financial regulations. If the payroll program is to continue to operate effectively, then these product updates must be regularly applied and accordingly the product update may be highly effectively used to distribute and apply a licensing control mechanism to a computer program that did not already have such a mechanism.
A further example of a situation in which the present technique is particularly advantageous is where the computer program is a malware scanner, such as a malware scanner that scans for computer viruses, worms, Trojans, banned files, banned words, banned images and the like. In order to provide effective malware protection such malware scanners must be regularly and methodically updated in order to have the latest scanner engines and malware definition data available for detecting and dealing with new malware threats as they are released and encountered. If a user does not apply the product updates, then the protection afforded by the malware scanner will decrease in effectiveness, particularly as the most dangerous malware threats tend to be the newly released items of malware which will only be detected by the latest malware definition data and scanner engines.
Whilst it is possible for the product update to be distributed in a wide variety of different ways, such as via physical media, the invention is particularly well suited to situations in which the product update is received via a network connection, such as via the internet being downloaded from the computer program provider's website. The increased availability of network connections via the internet has made the provision of product updates much easier and more routine and has generally lead to the more widespread practice of users regularly seeking and applying product updates to their computer programs which are already installed.
The effectiveness of the licensing control mechanisms are improved in embodiments in which the user is requested to enter licence key data each time the computer program is started, or at a periodic interval whilst the computer program is running. The licensing control mechanism may also preferably disable the computer program if a licence key is not entered within a predetermined period, such as a fixed number of days from the installation of the licensing control mechanism or a fixed number of starts of the computer program or the like.
Viewed from other aspects the invention provides a method of controlling the use of a computer program and an apparatus for controlling the use of a computer program in accordance with the above described techniques.
The above, and other objects, features and advantages of this invention will be apparent from the following detailed description of illustrative embodiments which is to be read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 schematically illustrates a network of computers and a stand alone computer connected via the internet to a web server of a computer program provider;
FIG. 2 is a flow diagram schematically illustrating the installation of a product update;
FIG. 3 is a flow diagram schematically illustrating the operation of a licensing control mechanism;
FIG. 4 schematically illustrates the updating of a malware scanner with a product update; and
FIG. 5 is a diagram schematically illustrating the architecture of a general purpose computer that may be used to implement the above described techniques.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates a network 2 comprising a server 4 and a plurality of clients 6 , 8 , 10 connected to the server 4 . The server 4 is in turn connected via the internet to the web server 12 of a computer program provider, such as an anti-virus scanner computer program provider (malware scanner provider). A stand alone computer 14 , such as a home user's computer, is also connected via the internet to the web server 12 .
The various computers 4 , 6 , 8 , 10 within the network 2 may all use and malware scanning computer program which incorporates a scanning engine and malware definition data which is kept updated by downloading product updates including the scanner engine, the malware definition data or a combination of both from the web server 12 . This update procedure may in some circumstances be automated. The stand alone computer 14 also operates the malware scanning computer program and will download the product updates from the web server 12 in accordance with its own requirements.
It will be appreciated that a malware scanning computer program must regularly be updated with product updates in order to remain effective since the latest virus definition data is required in order to protect against newly released items of malware. If a user does not download the product updates, then the malware scanner will progressively become less and less effective as the number of items of malware against which it does not provide protection will steadily increase. This situation is made worse as the items of malware that often provide the greatest threat are those most recently released and which require the latest versions of the product updates in order to be detected.
The regular, and possibly automated, download of product updates may be used by the computer program provider to distribute and apply a licensing control mechanism retrospectively to installed versions of their computer program which do not already have such a mechanism. Preventing unlicensed use of their computer program is highly commercially advantageous.
FIG. 2 schematically illustrates a flow diagram showing the action of a product update which adds a licensing control mechanism. At step 16 the system waits until a product update (SuperDAT) is downloaded, typically via a network connection through the internet from the computer program provider's web server. When the product update has been downloaded, then it is executed at step 18 . Step 20 serves to check whether the licensing control program is already installed on the computer to which the product update is being applied. If the licensing control program is not already installed, then processing proceeds to step 22 at which the licensing control program is installed. Processing then proceeds to step 24 where the malware scanner engine is replaced and step 26 where the malware definition data is replaced. It will be appreciated that in different product updates it may be that only one of the scanner engine or malware definition data is replaced or updated. It is also possible that the product update may not make changes to the scanner engine or malware definition data but may simply install the licensing controlled program where this is not already installed.
When the product update is installed, processing proceeds to step 28 at which the licensing control program is used to prompt the user to register the product and enter the licence key data. Step 30 determines the licence key data has been entered. If licence key data has not been entered, then step 32 sets a flag to prompt the user to enter this data at the next start of the malware scanning computer program.
If the test performed at step 20 indicated that the licensing controlled program was already installed, then processing proceeds to step 34 at which a check is made as to whether the maximum grace period during which the user is reminded to enter the licence key data has expired. If this period has expired and the licence key data has not been entered, then the rest of the product update will not be applied and instead the processing will proceed to step 36 at which a user message is displayed indicating that the computer program must be registered or licensed as indicated by entry of the required licence key in order that further product updates may be applied. If the licence key data is entered at this stage, then this is detected by step 38 and processing proceeds via step 40 and 42 to replace the scanning engine and malware definition data from the product update.
FIG. 3 illustrates the operation of the malware scanner once the licensing control mechanism has been installed. At step 44 the program is started and its first job is to run the licensing control program. Step 46 determines whether a valid licence key has already been entered in respect of this installation of the computer program. If a valid licence key has already been entered, then processing proceeds to step 48 at which the main malware scanner program is started and run.
If a licence key has not yet been entered, then processing proceeds from step 46 to step 48 at which a determination is made as to whether or not the grace period allowed for operation of the malware scanner with the licensing control mechanism installed and without licence key data entered has yet expired. A user may be given a period of, for example, thirty days during which they may obtain a licence key whilst continuing to be able to use the malware scanning computer program without the licence key in place. The licence control mechanism will store the date upon which it is installed and compare this with the current date in order to perform the determination indicated in step 48 . The licence control mechanism may also have anti-tamper measures in place to prevent the user adjusting the dates to obtain an extended grace period.
If the grace period has not yet expired, then processing proceeds to step 50 at which the user is prompted to enter the licence key data. If this key data is entered, then step 52 detects this and directs processing to step 54 at which the flag is cleared indicating that a user prompt for the licence key need not be generated the next time that the computer program is started. If the licence key is not entered, then this flag is not cleared.
If the determination at step 48 was that the grace period has expired, then processing proceeds to step 56 at which a message is displayed to the user indicating that the user is required to enter licence key data before the program will start. If such licence key data is entered, then this is detected at step 58 and processing is directed to step 54 at which the flag is cleared indicating that the computer program is licensed. If the licence key data is not entered, then step 58 terminates processing without starting the main malware scanning program. It will be appreciated that in some situations it may be that the importance of providing effective malware protection means that a computer program provider will continue to allow the program to be run even if the grace period has expired either by way of an exceptional circumstance or as a general policy. This aspect of the configuration may also be dynamic in the sense that the computer program provider may by virtue of an update allow emergency continued use of the computer program even when the grace period has expired should a particularly damaging item of malware be prevalent as a matter of goodwill to unlicensed users.
FIG. 4 illustrates the updating of a malware scanner in accordance with the present technique. The existing installed malware scanner 60 has a scanner engine and malware definition data both at version level N. This malware scanner 60 is updated by the application of a product update (SuperDAT) to form an updated malware scanner 62 in which the scanner engine and malware definition data are both advanced to the version level (N+1) and a licence control mechanism and licence key data storage are also added.
FIG. 5 schematically illustrates a general purpose computer 200 of the type that may be used to implement the above described techniques. The general purpose computer 200 includes a central processing unit 202 , a random access memory 204 , a read only memory 206 , a network interface card 208 , a hard disk drive 210 , a display driver 212 and monitor 214 and a user input/output circuit 216 with a keyboard 218 and mouse 220 all connected via a common bus 222 . In operation the central processing unit 202 will execute computer program instructions that may be stored in one or more of the random access memory 204 , the read only memory 206 and the hard disk drive 210 or dynamically downloaded via the network interface card 208 . The results of the processing performed may be displayed to a user via the display driver 212 and the monitor 214 . User inputs for controlling the operation of the general purpose computer 200 may be received via the user input output circuit 216 from the keyboard 218 or the mouse 220 . It will be appreciated that the computer program could be written in a variety of different computer languages. The computer program may be stored and distributed on a recording medium or dynamically downloaded to the general purpose computer 200 . When operating under control of an appropriate computer program, the general purpose computer 200 can perform the above described techniques and can be considered to form an apparatus for performing the above described technique. The architecture of the general purpose computer 200 could vary considerably and FIG. 5 is only one example.
Although illustrative embodiments of the invention have been described in detail herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications can be effected therein by one skilled in the art without departing from the scope and spirit of the invention as defined by the appended claims.
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A product update is used to add a licensing control mechanism to an installed computer program. The computer program is preferably a malware scanner or other program which requires regular product updating in order to remain effective in its normal functionality.
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FIELD OF THE INVENTION
[0001] The present invention relates to mobile platform passenger seats. In particular, the present invention relates to an expandable seat track cover that covers portions of a seat track between two adjacent seats.
BACKGROUND OF THE INVENTION
[0002] Aircraft passenger seats are fixedly secured within an aircraft passenger cabin through cooperation with a seat track. The seat track typically extends the entire length of the passenger cabin. The seats are secured to the seat track at spaced apart intervals along the seat track. Therefore, the portions of the seat track between the seats are not used to secure the seats. The portions of seat track between the seats are typically covered by a seat track cover.
[0003] The distance between the passenger seats, or seat pitch, varies depending on, for example, the aircraft operator, the class of service, the location of the seat within the passenger cabin, and the purpose of the aircraft. It is not uncommon for one aircraft to have a wide range of different seat pitches. Consequently, numerous seat track covers of numerous different sizes must be manufactured and kept on hand to accommodate the different seat pitches, thus increasing the cost of manufacturing and storing the seat tracks covers and increasing the difficulty and time required to install the seat track covers.
[0004] In view of the forgoing, it would be highly desirable to provide a seat track cover that is expandable to cover the portions of the seat track between two seat groups regardless of the distance between the seat groups. It is further desirable that the seat track cover be capable of transferring data and/or electrical power between the seat groups.
SUMMARY OF THE INVENTION
[0005] In one preferred form, the present invention provides for a seat track cover adapted to be secured over a seat track, where the seat track extends between a first seat and a second seat. The seat track cover includes a first portion and a second portion to form a two piece assembly that allows the overall length of the cover to be adjusted to a desired length. In this manner, the length of the seat track can be tailored to match the length of the uncovered portion of the seat track, thus eliminating the need to maintain covers of various fixed lengths to suit specific applications.
[0006] In one preferred form, the invention provides for a seat track cover for covering portions of a seat track between a first seat and a second seat that are both mounted to the seat track, and where the seat track is used on a mobile platform. The seat track cover includes an upper portion, side walls depending from the upper portion. The overall length of the seat track cover is adjustable.
[0007] The invention still further provides for a method for covering portions of a seat track located between a first seat and a second seat. The method comprises forming a cover having a first portion and a second portion. The second portion is slidably coupled to the first portion so that it can extend from the first portion at a variety of different distances to precisely match the distance between the first seat and the second seat.
[0008] The features, functions, and advantages can be achieved independently in various embodiments of the present inventions or may be combined in yet other embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:
[0010] FIG. 1 is a perspective view of a number of aircraft passenger seat groups secured to a seat track with the portions of the seat track between the seat groups covered by a seat track cover according to the present invention;
[0011] FIG. 2 is a perspective view of a seat track cover according to an embodiment of the present invention;
[0012] FIG. 3 is a perspective view of a first portion of the seat track cover of FIG. 2 ;
[0013] FIG. 4 is a cross-sectional view taken along line 4 - 4 of FIG. 2 ;
[0014] FIG. 5 is a side view showing the seat track cover of FIG. 2 positioned between and connected to two seat legs of two different seat groups;
[0015] FIG. 6 is a perspective view of a seat track cover according to another embodiment of the invention;
[0016] FIG. 7A is an expanded view illustrating interaction between first fingers and second fingers of the seat track cover of FIG. 6 according to an embodiment of the present invention;
[0017] FIG. 7B is an expanded view illustrating interaction between first fingers and second fingers of the seat track cover of FIG. 6 according to another embodiment of the present invention;
[0018] FIG. 8 is a side perspective view of a seat track cover according to another embodiment of the present invention, the seat track cover having a power bus;
[0019] FIG. 9 is a perspective view of the seat track cover of FIG. 2 having a false upper portion;
[0020] FIG. 10 is a perspective view of a seat track cover according to another embodiment of the present invention;
[0021] FIG. 11 is an exploded view of the seat track cover of FIG. 10 ;
[0022] FIG. 12 is a cross-sectional view taken along line 12 - 12 of FIG. 10 ;
[0023] FIG. 13 is a perspective view of an unassembled seat track cover according to another embodiment of the present invention; and
[0024] FIG. 14 is an assembled plan view of the seat track cover of FIG. 13 , the seat track cover rotatably secured to a seat leg.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.
[0026] FIG. 1 illustrates a portion of an aircraft passenger cabin 10 equipped with a number of seat track covers 12 according to a preferred embodiment of the present invention. A seat track 14 is recessed within an aircraft passenger cabin floor 16 . A number of spaced apart passenger seat groups 18 are secured to the seat track 14 . The seat track covers 12 are positioned between the seat groups 18 and cover the portions of the seat track 14 between the seat groups 18 . It will be appreciated that the present invention is not limited to use in aircraft passenger cabins, but can be implemented in any form of mobile platform such as a ship, train, bus, motor-craft, etc., as well as on any stationary platform such as in theatre seats and stadium seats.
[0027] With additional reference to FIG. 2 , the seat track cover 12 generally includes a first portion 20 and a second portion 22 . The first portion 20 slidingly receives the second portion 22 to allow the overall length of the cover 12 to be varied as needed. Extending through both the first portion 20 and the second portion 22 is an optional cable 24 .
[0028] With additional reference to FIGS. 3 and 4 , the first portion 20 generally includes an upper portion 26 and a pair of side walls 28 that depend from the upper portion 26 . The upper portion 26 is illustrated as having a crowned portion, but can also be planar or any other suitable shape. Extending from the upper portion 26 is a seat leg shroud 30 sized to receive a portion of a rear seat leg.
[0029] Referring to FIG. 3 , the side walls 28 are joined by a bottom portion 32 extending therebetween. Each side wall 28 includes a flange 34 . The bottom portion 32 includes a tongue or tab 36 . The tab 36 is narrower than the width of the rest of the bottom portion 32 and defines two slots 38 between the tab 36 and each side wall 28 . The slots 38 are at least wide enough to receive a portion of the second portion 22 .
[0030] Each flange 34 is typically angled to engage portions of the underside of the floor 16 on either side of the seat track 14 . However, each flange 34 can include any type of detail or be of any suitable shape to promote cooperation between the flange 34 and the floor 16 . Each side wall 28 is at least somewhat flexible to allow its flange 34 to engage the floor 16 in a snap-fit manner.
[0031] Referring to FIG. 2 , the second portion 22 of the seat track cover 12 is similar in construction to the first portion 20 . The second portion 22 includes an upper portion 40 and a pair of side walls.
[0032] The upper portion 40 is substantially similar to the upper portion 26 and the description of the upper portion 26 equally applies to the upper portion 40 . However, the upper portion 40 has dimensions that are slightly smaller than the upper portion 26 so that the first portion 20 can receive the second portion 22 . The upper portion 40 includes a seat leg shroud 44 that extends upward from the upper portion 40 . The seat leg shroud 44 is sized to receive a portion of a front seat leg.
[0033] The side walls 42 also each include a flange 46 . The flanges 46 are substantially similar to the flanges 34 of the first portion 20 and are angled to permit cooperation with the floor 16 . Referring to FIG. 4 , the side walls 42 further include a lower portion 48 ( FIG. 4 ) extending therebetween. The lower portion 48 extends substantially the entire length of the second portion 22 . The second portion 22 has overall dimensions that are smaller than the first portion 20 to permit the first portion 20 to receive the second portion 22 . Also, the portion of the flanges 46 nearest the first portion 20 are sized smaller than the portion of the flanges 46 furthest from the first portion 20 to allow the first portion 20 to receive the second portion 22 and to provide a region of the flanges 46 that have the same width as the flanges 34 to promote cooperation between the cover 12 and the undersurface of the floor 16 .
[0034] With further reference to FIG. 4 , this cross-sectional view taken along line 4 - 4 of FIG. 2 illustrates the cooperation between the first portion 20 and the second portion 22 . The cable 24 is not illustrated in FIG. 4 for clarity. The first portion 20 slidably receives the second portion 22 with the upper portion 40 positioned below the upper portion 26 and the side walls 42 positioned between the side walls 28 . The tab portion 36 of the first portion 20 is positioned atop the lower portion 48 of the second portion 22 . The side walls 42 of the second portion 22 are seated within the slots 38 of the first portion 20 .
[0035] As illustrated in FIG. 2 , the cable 24 extends from one end of the seat track cover 12 to the other end and through both the first portion 20 and the second portion 22 . The cable 24 includes a first connector 50 at one end of the cable 24 and a second connector 52 at a second end of the cable 24 opposite the first end. The cable 24 is seated within the cover 12 such that the first connector 50 is at the exposed end of the first portion 20 and the second connector 52 is at the exposed end of the second portion 22 . The first connector 50 and the second connector 52 are electrically or optically connected by conductors 54 . The length of the conductors 54 is at least equal to the approximate length of the seat track cover 12 when the second portion 22 is fully extended from the first portion 20 to allow the cover 12 to fully extend to accommodate large seat pitch lengths. When the second portion 22 is not fully extended, excess length of the conductors 54 is folded within at least one of the first side wall 28 and the second side wall 42 . While the conductors 54 are illustrated as a ribbon cable, the conductors 54 can be any suitable type of cabling that can conduct electricity and or data signals, such as a coaxial cable, a fiber optic cable, a copper wire, a coiled telephone cord, a spring loaded cord, etc.
[0036] With further reference to FIG. 5 , the seat track cover 12 is illustrated installed between two seat groups 18 . In particular, the seat track cover 12 is installed between a front seat leg 56 of one seat group 18 and a rear seat leg 58 of a neighboring seat group 18 . The seat track cover 12 is sized, by slidably extending or retracting the second portion 22 relative to the first portion 20 , to completely extend between the front seat leg 56 and the rear seat leg 58 . The seat track cover 12 is orientated such that the first portion 20 abuts the rear seat leg 58 and the second portion 22 abuts the front seat leg 56 . However, this orientation can be reversed as well.
[0037] The front seat leg 56 includes a front outlet 60 . The front outlet 60 is sized and configured to connect with the second connector 52 . The front outlet 60 is in cooperation with the electronic components of the seat group 18 , such as any audio/video equipment, computer networking equipment, and/or electrical power outlets, to transfer electrical power and data signals to and from the seat group 18 . The rear seat leg 58 includes a rear outlet 62 that is sized and configured to connect with the first connector 50 . Like the front outlet 60 , the rear outlet 62 is in cooperation with the electronic components of its associated seat group.
[0038] The cover 12 is positioned between the front seat leg 56 and the rear seat leg 58 such that the first connector 50 cooperates with the rear outlet 62 of the rear seat leg 58 and the second connector 52 cooperates with the front outlet 60 to provide an electrical and/or optical connection between the two seat groups 18 . The connection between the first connector 50 and the rear outlet 62 is at least partially covered by and protected by the seat leg shroud 30 . The connection between the second connector 52 and the front outlet 60 is covered and protected by the seat leg shroud 44 . To fully span the distance between the front seat leg 56 and the rear seat leg 58 and provide this connection, the cover 12 is extended or retracted as needed by extending the second portion 22 from within the first portion 20 , or retracting the second portion 22 within the first portion 20 . The seat track cover 12 is secured in place between the front seat leg 56 and the rear seat leg 58 by securing the flanges 46 and 34 beneath the floor 16 in the region of the seat track 14 .
[0039] With reference to FIG. 6 , a seat track cover according to another embodiment of the present invention is illustrated at 100 . The seat track cover 100 is similar to the seat track cover 12 in that it includes a first portion 102 and a second portion 104 . The cable 24 extends the length of the cover 100 through both the first portion 102 and the second portion 104 .
[0040] The first portion 102 includes a plurality of first fingers 106 . The fingers 106 are spaced apart and are open at one end of the first portion 102 . The first portion 102 further includes a recess 108 . The recess 108 includes a slit 110 in a wall portion 111 that allows the cable 24 to extend into the recess 108 . The flanges 112 extend from beneath the first portion 102 . The flanges 112 are substantially similar to the flanges 34 of the seat track cover 12 . Thus, the description of the flanges 34 of the seat track cover 12 equally applies to the flanges 112 .
[0041] The second portion 104 includes a plurality of fingers 114 . Like the fingers 106 , the fingers 114 are spaced apart and open at one end of the second portion 104 . The second portion 104 also includes flanges 116 . The flanges 116 are similar to the flanges 34 and 46 of the seat track cover 12 and therefore, the description of the flanges 34 and 46 equally applies to the flanges 116 .
[0042] The first portion 102 cooperates with the second portion 104 and slidingly receives the second portion 104 . The fingers 106 of the first portion 102 interlock with the fingers 114 of the second portion 104 to provide the cooperation between the first and second portions 102 and 104 . A small gap (not shown) is provided between the fingers 106 and the fingers 114 to accommodate the conductors 54 of the cable 24 , as described below.
[0043] With reference to FIG. 7A , to insure proper vertical alignment between the first portion 102 and the second portion 104 , the fingers 106 of the first portion 102 include recesses 118 that extend the length of the fingers 106 and the fingers 114 of the second portion 104 include protrusions 120 that extend the length of the fingers 114 . The recesses 118 cooperate with the protrusions 120 to insure vertical alignment between the first portion 102 and the second portion 104 . The recesses 118 and the protrusions 120 can be of various different shapes, such as having matching square shapes 114 a and 118 a in FIG. 7B .
[0044] With continued reference to FIG. 6 , the cable 24 is inserted within the seat track cover 100 such that the first connector 50 is at the exposed end of the first portion 102 and the second connector 52 is at the exposed end of the second portion 104 . The conductors 54 extend between the first and second connectors 50 and 52 . Specifically, the conductors 54 extend from the first connector 50 to within the recess 108 . From the recess 108 the conductors 54 extend through the slit 110 and along the length of the fingers 106 of the first portion 102 and along the length of the fingers 114 of the second portion 104 to the second connector 52 within the small gap between the fingers 106 and 114 . The recess 108 accommodates excess portions of the conductors 54 that are required to span the distance between the first connector 50 and the second connector 52 when the second portion 104 is fully extended from the first portion 102 . To secure the connector 54 in position, the connector 54 can optionally be secured, using a suitable adhesive or other fastening device or method, to the fingers 114 of the second portion 104 .
[0045] The seat track cover 100 is installed between the front seat leg 56 and the rear seat leg 58 to provide a connection between the first connector 50 and the second connector 52 in substantially the same manner that the seat track cover 12 is. Therefore, the description of the installation of the seat track cover 12 equally applies to the seat track cover 100 . However, to cover the recess 108 , the fingers 106 , and the fingers 114 , a shield 122 can be employed. The shield 122 is positioned over the cover 100 and can be secured either to the cover 100 or to the portions of the floor 16 surrounding the cover 100 . The shield 122 can include the seat leg shroud 44 to cover the connection between the second connector 52 and the front outlet 60 of the front seat leg 56 . The shield 122 can further include the seat leg shroud 30 to cover the connection between the rear outlet 62 and the first connector 50 . The shield 122 can include a seal to prevent liquids and other foreign materials from contacting the cover 100 . The shield 122 can be made of any suitable material, such as carpet or at least have a carpet covering.
[0046] With additional reference to FIG. 8 , a seat track cover according to another embodiment of the present invention is illustrated at 200 . The structure of the seat track cover 200 is substantially similar to the structure of the seat track cover 12 . Therefore, the portions of the seat track cover 200 that are identical to the seat track cover 12 are designated with like reference numbers having a prime symbol and the description of these like elements provided above equally applies to the seat track cover 200 .
[0047] The seat track cover 200 does not include the cable 24 as the cover 12 does. Instead, the seat track cover 200 has an internal power bus 202 for conducting signals and/or power. The power bus 202 extends through both the first portion 20 ′ and the second portion 22 ′. The portion of the power bus 202 in the first portion 20 ′ includes a plurality of contacts 204 . The contacts 204 extend along the top surface of the bottom portion 32 ′ of the first portion 20 ′. The contacts 204 can be of any suitable material for conducting electricity and/or optical signals. If electrical signals are being conducted, then the contacts 204 will preferably be formed from copper, gold, etc. The contacts 204 are in cooperation with a first connection port 206 that can mate with other devices to transfer signals to or from the power bus 202 .
[0048] The second portion 22 ′ also houses portions of the, power bus 202 including a connector block 208 . The connector block 208 is seated on the lower portion 48 ′ of the second portion 22 ′ at the end of the second portion 22 ′ received by the first portion 20 ′. The connector block 208 has a plurality of couplers 210 that typically correspond to the number of contacts 204 of the first portion 20 ′. Each of the couplers 210 mate with one of the contacts 204 of the first portion 20 ′ to conduct electricity and/or data between the first portion 20 ′ and the second portion 22 ′ regardless of how far the second portion 22 ′ is retracted within or extended from the first portion 20 ′.
[0049] Extending from the connector block 208 are a plurality of conductors 212 that connect the connector block 208 to a second connection port 214 . The connection port 214 is at the exposed end of the second portion 22 ′ opposite the connector block 208 . The connection port 214 connects with an external device to transfer signals to/from the power bus 202 .
[0050] The cover 200 is installed between the front seat leg 56 and the rear seat leg 58 in substantially the same manner that the cover 12 is. Therefore, the above description of the installation of the cover 12 equally applies to the cover 200 . Installation of the cover 200 between the seat legs 56 and 58 includes connecting the first connection port 206 to the rear outlet 62 and includes connecting the second connection port 214 to the front outlet 60 . Therefore, the seat track cover 200 provides a power and/or data connection between the two adjacent seat groups 18 of the rear seat leg 58 and the front seat leg 56 .
[0051] With additional reference to FIG. 9 , the seat track cover 12 is illustrated equipped with an optional false upper portion 300 . The false upper portion 300 is secured to the upper portion 40 of the second portion 22 using any suitable attachment method or device, such as an adhesive. The false upper portion 300 can also be integral to the second portion 22 . The width of the false upper portion 300 approximately equals the width of the upper portion 26 . Therefore, as the second portion 22 is extended from or retracted within the first upper portion 26 , it appears that only the part of the upper portion 40 not covered by the false upper portion 300 is changing length, making it difficult to discern that second portion 22 as a whole is changing length as it is extended from or retracted within the first portion 20 .
[0052] FIG. 9 illustrates the cover 12 as having a single false portion 300 . However, the cover 12 can include numerous false portions similar to the false portion 300 to disguise the fact that the second portion 22 is narrower than the first portion 20 . Additional devices and methods that can be used to disguise the fact that the second portion 22 is more narrow than the first portion 20 include coloring, shading, or varying the texture of the first and second portions 20 and 22 , including any false upper portions 300 that might be used, so that the half of the second portion 22 nearest the second seat leg shroud 44 has the same color, shade or texture as the upper portion 26 . Further, multiple false portions 300 can be used.
[0053] With additional reference to FIGS. 10-12 , a seat track cover according to another embodiment of the present invention is illustrated at 400 . The structure of the seat track cover 400 is substantially similar to the structure of the seat track cover 12 . Therefore, the portions of the seat track cover 400 that are substantially similar to the seat track cover 12 are designated with like reference numbers having a double prime symbol and the description of these like elements provided above equally applies to the seat track cover 400 .
[0054] The cover 400 generally includes a first portion 20 ″ and a second portion 22 ″. Extending between the first portion 20 ″ and the second portion 22 ″ is an optional cable 24 ″. The first portion 20 ″ generally includes an upper portion 26 ″ and side walls 28 ″ that depend from the upper portion 26 ″. A seat leg shroud 30 ″ extends from the upper portion 26 ″ and is sized to receive a portion of the rear seat leg 58 .
[0055] As seen in FIG. 11 , the first portion 20 ″ further includes a bottom portion 32 ″ that includes bosses 402 that cooperate with apertures 404 on the side walls 28 ″ to secure the bottom portion 32 ″ between the side walls 28 ″. The width of the bottom portion 32 ″ is less than the distance between the side walls 28 ″ to accommodate the second portion 22 ″ as described below and as illustrated in FIG. 12 . The side walls 28 ″ also include holes 406 to mount the cable 24 ″, as described below.
[0056] The second portion 22 ″ includes an upper portion 40 ″ and a pair of side walls 42 ″. The side walls 42 ″ include holes 408 to cooperate with the cable 24 ″ as further explained below. Extending inward from the bottom of each of the side walls 42 ″ are horizontal portions 410 that terminate near the center of the second portion 22 ″ at the flanges 46 ″. Unlike the flanges 46 , the flanges 46 ″ are moved inward from the side walls 42 ″ toward the center of the second portion 22 ″. Between the flanges 46 ″ is a gap 412 . The position of the flanges 46 inboard from the side walls 42 ″ permits the flanges to cooperate directly with the seat track 14 , instead of with the undersurface of the floor 16 as the flanges 46 do. Extending at least a portion of the length of the interior of the side walls 42 ″, just above the horizontal portions 410 , are side rails 413 .
[0057] The cable 24 ″ includes a first connector 50 ″ at one end and a second connector 52 ″ at an opposite end of the cable 24 ″ connected by conductors 54 ″. The first connector 50 ″ includes details 414 that extend from the sides of the first connector 50 ″. Likewise the second connector 52 ″ includes details 416 that extend from the sides of the second connector 52 ″.
[0058] To assemble the cover 400 , the cable 24 ″ is inserted within the first and second portions 20 ″ and 22 ″ by inserting the conductors 54 ″ through the gap 412 . Next, the first connector 50 ″ is inserted between the side walls 28 ″ so that the details 414 are received by the holes 406 to secure the first connector 50 ″ into position. Likewise, the second connector 52 ″ is inserted between the side walls 42 ″ and above the side rails 413 so that the details 416 are received by the holes 408 to secure the connector 52 ″ into position. Before or after the first connector 50 ″ is secured into position, the bottom portion 32 ″ is attached to the first portion 20 ″ by moving the bosses 402 into cooperation with the apertures 404 .
[0059] FIG. 12 is a cross sectional view taken along like 12 - 12 of FIG. 10 of the cover 400 as assembled. As illustrated in FIG. 12 , the second portion 22 ″ is seated within the first portion 20 ″. Further the bottom portion 32 ″ is positioned between the horizontal portions 410 and the side rails 413 . The cover 400 is positioned between the seat legs 56 and 58 to provide a data and/or electrical connection between the outlets 60 and 62 in substantially the same manner that the cover 12 is and therefore the above description of the positioning of the cover 12 between the seat legs 56 and 58 equally applies to the cover 400 , the only substantial difference being that the cover 400 is secured directly to the seat track 14 rather than the floor 16 .
[0060] With additional reference to FIGS. 13 and 14 , a seat track cover according to another embodiment of the present invention is illustrated at reference numeral 500 . The structure of the seat track cover 500 is similar to the structure of the seat track cover 12 . Therefore, the portions of the seat track cover 500 that are similar to the seat track cover 12 are designated with like reference numerals having a triple prime symbol (′″) and the description of these like elements provided above equally applies to the seat track cover 500 .
[0061] The cover 500 generally includes a first portion 20 ′″ and a second portion 22 ′″. The first portion 20 ′″ generally includes an upper portion 26 ′″, a pair of spaced apart side walls 28 ′″ that depend from the upper portion 26 ′″, and a bottom portion 32 ′″ that is approximately parallel to the upper portion 26 ′″ and spans the two side walls 28 ′″. The upper portion 26 ′″, the side walls 28 ′″, and the bottom portion 32 ′″ define a first aperture 502 .
[0062] A bracket assembly 504 extends from the upper portion 26 ′″. The bracket assembly 504 can include a first bracket 504 A and a second bracket 504 B. The first bracket 504 A is spaced apart from the second bracket 504 B at a distance great enough to accommodate either the front seat leg 56 ′″ or the rear seat leg 58 ′″ between the first and second brackets 504 A and 504 B. The bracket 504 A includes a through hole 506 A and the bracket 504 B includes a through hole 506 B. The through hole 506 A is aligned with the through hole 506 B. The bracket assembly 504 can be any suitable bracket assembly operable to pivotally mount the seat track 500 to either the front seat leg 56 ′″ or the rear seat leg 58 ′″.
[0063] The portions of the side walls 28 ′″ and the bottom portion 32 ′″ can be curved in the region proximate to the bracket assembly 504 , as illustrated in FIG. 13 , to provide the first portion 20 ′″ with a curved terminus at one end to facilitate pivoting of the cover 500 . Specifically, the bottom portion 32 ′″ is curved upward toward the upper portion 26 ′″. The side walls 28 ′″ are curved from the bottom portion 32 ′″ to the upper portion 26 ′″ in a plane at least substantially perpendicular to the upper portion 26 ′″.
[0064] The second portion 22 ′″ generally includes an upper portion 40 ′″, a pair of spaced apart side walls 42 ′″ that are generally perpendicular to the upper portion 40 ′″ and depend from the upper portion 40 ′″, and a lower portion 48 ′″ that is generally parallel to the upper portion 40 ′″ and extends between the side walls 42 ′″. The upper portion 40 ′″, the side walls 42 ′″, and the lower portion 48 ′″ define a second aperture 508 . The second aperture 508 is generally sized and shaped to receive the first portion 20 ′″.
[0065] The second portion 22 ′″ further includes a retainer 510 . As illustrated in FIG. 14 , the retainer 510 extends from one of the side walls 42 ′″ and the upper portion 40 ′″. The retainer 510 is generally rectangular and includes an upper portion 512 , an outer side portion 514 , a lower portion 516 , and an inner side portion 518 . The upper portion 512 and the lower portion 516 are generally parallel. The outer side portion 514 and the inner side portion 518 are generally parallel to each other and are generally perpendicular to the upper portion 512 and the lower portion 516 respectively. The outer side portion 514 extends between the upper portion 512 and the lower portion 516 . The inner side portion 518 extends from the upper portion 512 , but does not extend entirely to the lower portion 516 . The retainer 510 can be integral with the side portion 42 ′″ and/or the upper portion 40 ′″ or the retainer 510 can be a separate device that is secured to the second portion 22 ′″ using any suitable fastening means. The retainer 510 extends beyond the second aperture 508 and is offset from the remainder of the second portion 22 ′″ such that the retainer 510 is beyond the width of the upper portion 40 ′″, as best illustrated in FIG. 14 . The retainer 510 can be any suitable retainer operable to securely mount at least one of the first and second connectors 50 ′″ and 52 ′″ of the cable 24 ′″, as described in greater detail below.
[0066] The second portion 22 ′″ still further includes an extended portion 520 that extends from the upper portion 40 ′″ above the side wall 42 ′″ that is opposite to the retainer 510 . At least a part of the extended portion 520 extends beyond the width of the upper portion 40 ′″. The extended portion 520 , the retainer 510 , and the upper portion 40 ′″ generally define a “U” shaped receptacle 522 . The receptacle 522 is sized to receive and surround a portion of either the front seat leg 56 ′″ or the rear seat leg 58 ′″, as described in further detail below.
[0067] The first portion 20 ′″ is slidingly received by the second aperture 508 of the second portion 22 ′″. The first portion 20 ′″ may include a pair of details 524 that protrude from the surface of the side walls 28 ′″ that is opposite the first aperture 502 . The details 524 slidingly cooperate with recesses 526 to maintain cooperation between the first portion 20 ′″ and the second portion 22 ′″. The sliding cooperation between the details 524 and the recessed 526 also allows the first portion 20 ′″ to slide within the second aperture 508 to increase and decrease the overall length of the cover 500 .
[0068] The cable 24 ′″ extends the length of the cover 500 . The cable 24 ′″ is similar to the cable 24 except that the cable 24 ′″ includes only one connector, such as the connector 52 ′″. The connector 52 ′″ can be of any suitable size or shape that can be received by the retainer 510 . The connector 52 ′″ can be secured to the retainer 510 using any suitable fastening means, such as a press-fit, an adhesive, or a mechanical interlock. The conductors 54 ′″ are secured to the connector 52 ′″ and extend at least substantially the entire length of the cover 500 through the second aperture 508 and the first aperture 502 . The conductors 54 ′″ exit the first aperture 502 through an opening 530 proximate to the bracket assembly 504 .
[0069] The cover 500 is pivotally attached to either the rear seat leg 58 ′″ or the front seat leg 56 ′″. As illustrated in FIG. 14 , the cover 500 is secured to the front seat leg 56 ′″ by a pin 532 that cooperates with the through holes 506 A and 506 B of the brackets 504 A and 504 B respectively and holes 534 A and 534 B formed on opposing sidewalls of the front seat leg 56 ′″. The cover 500 can also be pivotally secured to the rear seat leg 58 ′″ in a similar manner. The cover 500 can also be pivotally secured to the rear seat leg 58 ′″ or the front seat leg 56 ′″ in any other suitable manner.
[0070] The seat leg of the adjoining seat group 18 that is opposite the seat leg that the cover 500 is pivotally secured to, such as the rear set leg 58 ′″ of FIG. 14 , can have an outlet assembly 540 . The outlet assembly 540 includes an outlet support bracket 542 and an outlet 544 . The outlet support bracket 542 is mounted to the rear seat leg 58 ′″, for example, using any suitable fastening means. The outlet 544 is mounted to the support bracket 542 using any suitable retaining means. The outlet 544 is exposed in the direction of the opposing seat leg, such as the front seat leg 56 ′″. The outlet 544 can be offset to the side of the rear seat leg 58 ′″, as illustrated in FIG. 14 , to permit cooperation with the second connector 52 ′″. The outlet 544 is usually offset on the side of the rear set leg 58 ′″ that is under the passenger seat and inboard from the aircraft aisle, at least when the cover 500 is used in an aircraft. The outlet 544 is in cooperation with the electronics of the seat group 18 associated with the rear seat leg 58 ′″.
[0071] In many applications, the cover 500 is pivotally secured to the desired seat leg, such as the front seat leg 56 ′″ or the rear seat leg 58 ′″, and the outlet assembly 540 is secured to the opposing seat leg, such as the rear seat leg 58 ′″ or the front seat leg 56 ′″, during assembly of the seat group 18 outside the passenger cabin 10 by the seat group manufacturer. During transport of the seat group 18 to the passenger cabin 10 , the cover 500 is rotated upward such that the cover 500 is approximately parallel with the front seat leg 56 ′″ or the rear seat leg 58 ′″. After the seat groups 18 are in position, the cover 500 is rotated downward to within the seat track 14 and the second portion 22 ′″ is extended from the first portion 20 ′″ and the second connector 52 ′″ is brought into connection with the outlet 544 to provide an electrical and/or optical connection between adjoining seat groups 18 .
[0072] While various preferred embodiments of the seat track cover have been disclosed, it will be appreciated that other features and aspects can be employed within the scope of the present invention. For example, any of the covers 12 , 100 , 200 , 300 , 400 , and 500 described above can include a first connector extension (not shown) extending from the first portion 20 and a second connector extension (not shown) extending from the second portion 22 . In this embodiment the cable 24 or the power bus 202 do not directly contact the front outlet 60 or the rear outlet 62 . Instead, the first and second connector extensions each receive one of the first connector 50 and the second connector 52 respectively and it is the first and second connector extensions that cooperate with the front outlet 60 and the rear outlet 62 respectively.
[0073] Further, the front outlet 60 and the rear outlet 62 of the front and rear seat legs 56 and 58 respectively can be movable or spring-loaded in a variety of different directions, such as horizontal relative to the floor 16 to facilitate connection with the covers 12 , 100 , 200 , 300 , 400 , and 500 . Still further, the first connector 50 and the second connector 52 , as well as the front outlet 60 and the rear outlet 62 , can be orientated in a variety of different directions in addition to the orientations illustrated, such as upward or downward in relation to the floor 16 .
[0074] Also, the power bus 202 can be positioned within the cover 200 at other areas besides the lower portion 48 and the bottom 32 , such as along the sides of the cover 200 and along an upper portion of the cover 200 .
[0075] Additionally, the covers 12 , 200 , 300 , 400 , and 500 can include more portions in addition to the portions 20 and 22 to increase the length of the covers 12 , 200 , 300 , 400 , and 500 . For example, the first and second portions 20 / 22 can be resized to accommodate a third portion between or on either side of the first and second portions 20 / 22 . The overall length of the covers 12 or 200 would then be increased by the length of the third portion. Similarly, the first and second portions 102 and 104 can be re-sized to accommodate additional portions between or on either side of the first and second portions 102 / 104 to increase the length of the cover 100 .
[0076] Also, any of the covers 12 , 100 , 200 , 300 , and 400 can be secured to at least one of the seat legs 56 and 58 , such as the cover 500 is. The covers 12 , 100 , 200 , 300 , and 400 can be pivotally secured to at least one of the seat legs 56 and 58 in any suitable manner, such as the manner in which the cover 500 is. Securing the seat legs 12 , 100 , 200 , 300 , 400 , and 500 to at least one of the seat legs 56 and 58 facilitates installation of the seat groups 18 within the passenger cabin 10 .
[0077] Finally, the position of the flanges 34 , 46 , 112 , and 116 can vary depending upon the surface that the cover is to engage. For example, any of the flanges can be positioned inward of the side walls, such as the flanges 46 ″ of the cover 400 ( FIG. 10 ) are to mate with the seat track 14 , or at the side walls, such as the flanges 34 / 46 of the cover 12 ( FIG. 2 ) are to mate with the under surface of the floor 16 . Further, one or more fasteners can be used to attach the covers 12 or 200 to the seat track 14 or the passenger cabin floor 16 .
[0078] Therefore, the present invention provides for a telescoping seat track cover that can expand and contract to cover the portions of the seat track between two seat groups regardless of the distance between the seat groups. The seat track cover can be wired to conduct data and/or electricity between the seat groups.
[0079] While various preferred embodiments have been described, those skilled in the art will recognize modifications or variations which might be made without departing from the inventive concept. The examples illustrate the invention and are not intended to limit it. Therefore, the description and claims should be interpreted liberally with only such limitation as is necessary in view of the pertinent prior art.
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A seat track cover having telescopically engaged first and second portions that enables an overall length of the seat track cover to be adjusted as needed to cover a portion of a seat track that separates two adjacent seats mounted to the seat tracks. A cable can be routed within the first and second portions to enable electrical or optical signals to be conducted between data/power connection ports on the seats. One embodiment includes mating conductive elements formed along the lengths of each of the first and second portions.
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BACKGROUND OF THE INVENTION
Anchoring objects to the ground is important for temporary structures such as tents. Ideally an anchor would require a lot of force to remove from the ground while it is working, yet be easily removed when desired. The anchor should also be small when not in use so it may be easily stored. Present solutions for having a great deal of holding power include auger type earth anchors that are difficult to install, quite large and usually heavy. There is a need for an anchor similar in size to a traditional tent stake, yet provides holding power comparable to an auger type anchor.
SUMMARY OF THE INVENTION
The present invention is a tie down anchor that is particularly useful when tying down objects to the ground and may take the place of ordinary tent stakes due to the tie down anchor's superior holding ability when compared to traditional tent stakes. The tie down anchor has a guide having an angled hole. A main stake extends downwardly from the guide and the main stake includes an aperture. A locking spike is adapted for being received in the angled hole. The aperture in the main stake is positioned to receive the locking stake when the locking stake passes through the angled hole.
The guide may include a stake aperture extending through the guide that is adapted for receiving the main stake. When used with a guide of this type, the main stake has a stop that locates the maximum depth the main stake may extend below the guide. The angled hole is adapted for guiding the locking spike through the aperture in the main stake when the stake extends to its maximum depth below the main stake.
In another aspect of the invention, the main stake may have a guide that is pivotally affixed to the main stake. The guide of this type has an angled hole adapted for receiving the locking stake. The guide is pivotal from a folded position adjacent to the main stake to another position in which the guide is substantially perpendicular to the main stake. A stop is included to limit movement of the guide to be substantially perpendicular to the main stake.
In yet another aspect of the invention, the main stake and guide are integrally joined and the main stake includes an angled hole adapted for guiding the locking spike through an aperture near the lower end of the main stake.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a tent stake of this invention;
FIG. 2 is a sectional view taken about the line 2 - 2 in FIG. 1 ;
FIG. 3 is a perspective view of another embodiment of the tent stake fully assembled;
FIG. 4 is a perspective view of the tent stake shown in FIG. 3 viewed from the opposite side as that of FIG. 3 ;
FIG. 5 is a perspective view of the tent stake shown in FIGS. 3-4 with its guides folded down;
FIG. 6 is an exploded perspective view of the tent stake shown in FIGS. 3-5 ;
FIG. 7 is a sectional view taken about the line 7 - 7 in FIG. 3 ;
FIG. 8 is a perspective view of another embodiment of the tent stake of the invention; and
FIG. 9 is sectional view taken about the line 9 - 9 in FIG. 8 .
DETAILED DESCRIPTION OF INVENTION
FIG. 1 shows the ground anchor 10 of the present invention in an exploded view. The ground anchor 10 is particularly useful for anchoring tents or other objects to the ground 12 . FIG. 2 shows a sectional view of the anchor 10 as used in the ground 12 . The anchor 10 has a guide 14 . The guide 14 has a stake aperture 18 adapted for receiving a main stake 20 and an angled hole 22 adapted for receiving a locking stake 24 . The angled hole 22 extends obliquely through the guide 14 and is angled toward the stake aperture 18 when traversing toward the ground 12 through the guide 14 . The stake aperture 18 has legs 25 and 26 that are straight slots through the entire thickness of the guide 14 . Leg 26 is shorter in length than leg 25 . The guide 14 may be made of a solid block of material, as shown in FIGS. 1 and 2 , or can be made of tubular stock. When the guide 14 is made of solid stock, as shown in FIGS. 1 and 2 , it is easier to insert the locking stake 24 and the main stake 20 into the guide 14 because there will be more bearing surface to guide each of the aforementioned parts through the guide 14 . However, in some instances it may be desirable to reduce weight by using a tubular construction as opposed to the solid construction shown in FIGS. 1 and 2 . The main stake 20 has flanges 30 , 31 that are perpendicular to each other. Standard angle stock may be used to manufacture the main stake 20 . One of the flanges 31 is shortened to leave a protrusion 34 near the top of the stake 20 . When the main stake 20 is made of standard angle stock having flanges of equal length, the short flange 31 is easily manufactured by removing stock from only one flange of the angle stock. A tie hole 35 is located in the protrusion 34 at the top of flange 31 ; however, this hole 34 could be located on the other flange 30 . The protrusion 34 prevents the main stake 20 from passing through the stake aperture 18 . The main stake 20 has a slot 38 near its lower end 40 . The lower end 40 is tapered to a point, as shown in FIG. 1 , to enhance the main stake's 20 ability to penetrate the ground 12 . FIG. 2 shows the ground anchor 10 as it is used in the ground 12 . The user of the ground anchor shown in FIG. 2 will first place the guide 14 in a desired location on the ground 12 . The main stake 20 will then be inserted into the stake aperture 18 . The legs 25 and 26 of the stake aperture 18 will allow for only one possible way to install the stake 20 within the aperture 18 . As such, the slot 38 will face the angled hole 22 . With the main stake 20 in the stake aperture, the user will then pound the main stake 20 into the ground 12 until it stops due to the protrusion 34 engaging the guide 14 , as shown in FIG. 2 . When the protrusion 34 engages the guide 14 , this will repeatably position the slot 38 in the same location below the guide 14 . This corresponds to the fully driven position because the main stake 20 cannot be driven any further. With the main stake 20 securely in the ground in its fully driven position, the locking stake 24 will be placed into the angled hole 22 . The angled hole 22 positions the locking stake 24 so it will intersect with the slot 38 . The user will then drive the locking stake 24 until it stops against the guide 14 . This is the fully driven position of the locking stake 24 . The slot 38 has a length chosen to allow for potential variation in the vertical location of the locking stake 24 relative to the guide 14 . This variation in vertical height of the locking stake 24 , particularly the lower end passing through slot 38 , may be the result of clearance in the angled hole 22 . This clearance may result from tolerance in the angled hole size 22 , variation in the outer diameter of the locking stake 24 , clearance between the main stake 20 and stake aperture 18 , or potential tolerance in the angularity of the angled hole relative to the guide. The slot 38 size in the main stake 20 is chosen so that, even with the maximum tolerances and necessary clearance between the locking stake 24 and angled hole 22 , the angled hole 22 will guide the locking stake 24 to intersect with the slot 38 . This intersecting relationship, as shown in FIG. 2 , produces a secure anchor to the ground 12 . This intersecting relationship may also be had by using the stake aperture 18 in the place of the angled hole 22 , so it is the stake aperture 18 that is at an oblique angle relative to the guide 14 and the ground 12 , and the locking stake 24 would be perpendicular to the ground 12 . The force required to remove the anchor, as shown in FIG. 2 , from the ground 12 will necessarily be much larger than that required to remove a single stake. Generally when removing a single piece stake, such as that in the prior art, the easiest way to remove the stake is to pull along the longitudinal axis of the stake. Also, in the case of the present invention, pulling directly upward on the main stake 20 is the easiest way to remove it from the ground. However, the main stake 20 will have the locking stake 24 interlocked within it so a force pulling upward on the main stake 20 , along its longitudinal axis, will not easily dislodge it from the ground 12 . The user may tie a rope through hole 35 . It is also contemplated that a tie hole 35 may be located on the guide 14 , itself. Removing the ground anchor 10 from the ground may be accomplished by first pulling the locking stake 24 , then the main stake 20 .
Guides 50 may also be attached to a main stake 52 , as shown in FIG. 3 . In this case, each guide 50 is pivotally attached with a rivet 56 to the main stake 52 near its upper end. This pivotal attachment allows the guides 50 to be folded down along the main stake 52 , as shown in FIG. 5 , and then unfolded, as shown in FIGS. 3 and 4 . The limit to which the guides 50 may be folded upward is shown in FIG. 4 . The guides 50 are prevented from pivoting upward when they reach the ninety degree position. Each guide 50 has a rivet 58 above it that catches each guide 50 , as shown in FIG. 4 . Each guide 50 has an angled hole 60 extending through a flange 62 . The angled holes 60 are adapted for receiving a locking stake 64 . The angled holes 60 are set at slightly different angles with respect to their corresponding guides 50 . This is necessary because flanges 68 on the main stake have slots 70 staggered in their vertical position, as shown in FIG. 3 . The upper slot 70 ′ has its lowermost portion above the uppermost portion of the lower slot. The different vertical heights of the slots 70 , on their respective flanges 68 , are necessary to prevent locking stakes 64 from hitting each other when driven through their corresponding angled holes 60 . FIG. 3 shows how the locking stakes 64 pass near each other, but do not touch. The main stake 52 includes a tie hole 74 for receiving a rope.
A main stake 80 may also have an integral guide 82 extending from the main stake 80 . In this case, the guide 82 has an angled hole 84 to guide a locking stake 88 through a slot 90 near the lower end of the main stake 80 . Due to the fact that the main stake 80 and the guide 82 are integral, there is less overall variation in the final position of the locking stake 88 when it is fully driven into the angled hole 84 , as shown in FIG. 9 . Thus, the slot 90 does not need to be as long as would otherwise be necessary if there were more tolerance between separate parts that would increase the variation in the final position of the locking stake 88 . Tie holes 92 are located in the top of the main stake 80 and on opposite sides of the main stake 80 in the guide 82 .
This invention is not limited to the details above, but may be modified within the scope of the following claims.
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A tie down anchor that is particularly useful when tying down objects to the ground and may take the place of ordinary tent stakes due to the tie down anchor's superior holding ability when compared to traditional tent stakes. The tie down anchor has a guide having an angled hole. A main stake extends downwardly from the guide and the main stake includes an aperture. A locking spike is adapted for being received in the angled hole. The aperture in the main stake is positioned to receive the locking stake when the locking stake passes through the angled hole. The stake of this invention is small, light, and of a comparable size to traditional tent stakes.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. patent application Ser. No. 14/320,300 filed Jun. 30, 2014, which claims priority to U.S. Provisional Application No. 61/841,716, filed Jul. 1, 2013, both of which are hereby incorporated by reference in their entireties.
STATEMENT OF GOVERNMENT SUPPORT
[0002] This invention was made with government support under Contract No. DE-AC02-05CH11231 awarded by the U.S. Department of Energy, under Contract No. DE-AC52-07NA27344 awarded by the U.S. Department of Energy, under Grant X10-8049-C awarded by the Air Force Office of Scientific Research. The government has certain rights in this invention.
BACKGROUND
[0003] Boron nitride (BN) forms bonding configurations similar to carbon. While sharing many of the same robust mechanical and thermal properties of graphite (Cohen et al., Phys. Today, 2010, 63:34-38; Dresselhaus et al., Philos. Trans. R. Soc., 2004, 362:2065-2098), the polar nature of the boron-nitrogen bond in planar (i.e., hexagonal) BN makes BN an optically transparent insulator (Robertson et al., Phys. Rev. B, 1984, 29:2131-2137), with different chemistry on the surface of the hexagonal lattice. As a consequence, BN-based materials are more resistant to oxidation than graphene-based materials (Chen et al., Appl. Phys. Lett., 2004, 84:2430-2432). BN also has enhanced physisorption properties due to the dipolar fields near its surface (Jhi et al., Phys. Rev. B, 2004, 69:245407). BN has been shown to surpass carbon in its ability to store gases such as hydrogen (Borek et al., Langmuir, 1991, 7:2844-2846; Li et al., Nanotechnology, 2013, 24:155603; M a et al., J. Am. Chem. Soc., 2002, 124:7672-7673; Kim et al., J. Mater. Chem. A, 2013, 1:1014-1017; Weng et al., ACS Nano, 2013, 7:1558-1565; Janik et al., Langmuir, 1994, 10:514-518), and is a very effective and reusable cleanup agent for hydrocarbons (Lei et al., Nat. Commun., 2013, 4:1777). Also, despite its relative chemical inertness, BN surfaces can be functionalized (Ikuno et al., Solid State Commun., 2007, 142:643-646; Lin et al., J. Phys. Chem. C, 2010, 114:17434-17439), allowing for their incorporation into composites (Zhi et al., Adv. Funct. Mater, 2009, 19:1857-1862), as well as their use as scaffolds for nanoparticles in catalysis and other applications (Sainsbury et al., J. Phys. Chem. C, 2007, 111:12992-12999).
[0004] Previous synthetic routes for BN-type aerogels and related meso-scale assemblies have included templated growth from existing porous structures such as zeolites (Schlienger et al., Chem. Mater., 2012, 24:88-96), gelation of colloidal BN suspensions (Jung et al., Sci. Rep., 2012, 2:849), and various high temperature reactions of boron and nitrogen containing compounds (Dibandjo et al., J. Eur. Ceram. Soc., 2007, 27:313-317; Paine et al., J. Inorg. Organomet. Polym., 1992, 2:183-195.). Despite a number of promising fields of application, research in this area has been slow due to the often toxic and volatile precursors involved and the limited synthetic routes to high quality BN. Furthermore, these synthesis methods have generally resulted in compounds of mixed BN phases and disordered or turbostratic stacking of planar sheets, corresponding to a crystal structure found in materials where atomic planes are inclined and rotated randomly with respect to one another.
[0005] Thus, a need exists for BN-based materials with improved structural quality.
SUMMARY
[0006] One aspect of the invention described herein relates to an aerogel material comprising boron nitride, the boron nitride having an ordered crystalline structure.
[0007] In some embodiments, the ordered crystalline structure includes atomic layers of hexagonal boron nitride laying on top of one another, and wherein atoms contained in a first layer are superimposed on atoms contained in a second layer.
[0008] In some embodiments, atomic planes of the boron nitride have an interplanar distance of about 3.3 Angstroms.
[0009] In some embodiments, the boron nitride described herein has a degree of crystallinity of at least 30%, or a degree of crystallinity of at least 40%, or a degree of crystallinity of at least 50%, or a degree of crystallinity of at least 70%, either by weight or by volume. In some embodiments, the boron nitride described herein does not have a substantially disordered crystalline structure.
[0010] In some embodiments, the aerogel described herein comprises sheets of boron nitride that are covalently bonded to one another. In some embodiments, at least 30% of the boron nitride sheets, or at least 40% of the boron nitride sheets, or at least 50% of the boron nitride sheets, or at least 70% of the boron nitride sheets, are covalently crosslinked with one another. In some embodiments, the aerogel consists essentially of sheets of boron nitride that are covalently bonded to one another.
[0011] In some embodiments, less than 50%, or less than 40%, or less than 30%, or less than 10% of the boron nitride sheets are associated with other boron nitride sheets by van der Waals force only. In some embodiments, the aerogel is substantially free of boron nitride sheets that are associated with other boron nitride sheets by van der Waals force only.
[0012] In some embodiments, the aerogel described herein comprises a three-dimensional network of sp 2 -bonded boron nitride. In some embodiments, at least 50% of the boron nitride, or at least 70% of the boron nitride, or at least 90% of the boron nitride, or at least 95% of the boron nitride, are sp 2 -bonded boron nitride.
[0013] In some embodiments, the aerogel described herein comprises at least about 70 atomic percent boron nitride, or at least about 80 atomic percent boron nitride, or at least about 90 atomic percent boron nitride, or at least about 95 atomic percent boron nitride. In some embodiments, the aerogel described herein consists essentially of boron nitride.
[0014] In some embodiments, the aerogel described herein comprises less than 10 atomic percent carbon, or less than 5 atomic percent carbon, or less than 2 atomic percent carbon, or less than 1 atomic percent carbon.
[0015] In some embodiments, the aerogel described herein has a surface area of about 350 meters squared per gram to 3000 meters squared per gram, or a surface area of about 350 meters squared per gram to 1050 meters squared per gram, or a surface area of about 1500 meters squared per gram to 3000 meters squared per gram.
[0016] In some embodiments, the boron nitride comprises hexagonal boron nitride.
[0017] In some embodiments, the aerogel comprises sheets of boron nitride, wherein the sheets of boron nitride include about 5 atomic layers of boron nitride or less. In some embodiments, the aerogel comprises sheets of boron nitride, wherein the sheets of boron nitride include an average of about 6-8 atomic layers of boron nitride.
[0018] In some embodiments, the aerogel comprises sheets of boron nitride, wherein at least a portion of the sheets of boron nitride form slit-shaped pore structures about 400 nanometers to 600 nanometers wide and about 2 microns to 4 microns long.
[0019] In some embodiments, the boron nitride has a white color.
[0020] In some embodiments, the aerogel has a mass density of about 50 milligrams per cubic centimeter to 150 milligrams per cubic centimeter.
[0021] In some embodiments, the aerogel comprises sheets of boron nitride, wherein the sheets of boron nitride have planar surfaces having dimensions of about 10 microns to 50 microns by about 10 microns to 50 microns.
[0022] In some embodiments, pores of the aerogel have diameters of about 2 nanometers to 50 nanometers.
[0023] Another aspect of the present invention described herein relates a method for making the aerogel material described herein, comprising: (a) providing boron oxide and an aerogel comprising carbon; (b) heating the boron oxide to melt the boron oxide and heating the aerogel; (c) mixing a nitrogen-containing gas with boron oxide vapor from molten boron oxide; and (d) converting at least a portion of the carbon of the aerogel to boron nitride.
[0024] In some embodiments, the aerogel comprising carbon in (a) includes graphitic carbon. In some embodiments, the aerogel comprising carbon in (a) is a graphene aerogel. In some embodiments, at least 50%, or at least 70%, or at least 90% of the graphene sheets are chemically crosslinked to other graphene sheets by covalent bonds. In some embodiments, less than 50%, or less than 30%, or less than 20%, or less than 10% of the graphene sheets are physically associated with other graphene sheets by van der Waals force only.
[0025] In some embodiments, at least about 70 atomic percent of the carbon, or at least about 80 atomic percent of the carbon, or at least about 90 atomic percent of the carbon, or at least about 95 atomic percent of the carbon is converted to boron nitride in (d).
[0026] In some embodiments, the method is substantially free of the use of additional promoters such as metal oxides for converting carbon to boron nitride. In some embodiments, the method does not comprise a step of burning off residual carbon.
[0027] The ordered crystalline structure described herein can comprise, for example, perfectly order crystalline structure as well as crystalline structure that differ slightly from perfectly order crystalline structure, such as where atoms in a first layer are displaced relative to atoms in a second layer by no more than 4 Angstroms, or no more than 3 Angstroms, or no more than 2.5 Angstroms, or no more than 2 Angstroms.
[0028] These and other features, together with the organization and manner of operation thereof, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Note that the relative dimensions of the following figures may not be drawn to scale.
[0030] FIG. 1 shows an example of a method for synthesizing an aerogel comprising boron nitride.
[0031] FIG. 2 shows an example of a photograph of a graphene aerogel.
[0032] FIG. 3 shows an example of a photograph the graphene aerogel after conversion to a BN aerogel.
[0033] FIG. 4 shows an example SEM image of a BN aerogel. The structure is composed of many ultrathin, wrinkled sheets several micrometers long and folded into each other, forming slit-shaped macropores. Scale bar is 5 μm.
[0034] FIG. 5 shows example TEM images of original graphene aerogel (a, c) and converted BN aerogel (b, d). The lower-magnification TEM images (a, b) show that both aerogels are porous with feature sizes of about 30 nm. The higher-magnification TEM images (c, d) show that the aerogels comprise layered structures, indicated by the parallel, dark fringes. Upon conversion to BN, the layered structures become more crystalline with sharp transitions between the facets (d), compared to the more meandering layers observed in the graphene aerogels (c). In addition, the average number of wall for the constituent sheets increases from 2 to 3 in the case of the graphene gels to 6 to 8 for the BN gels. Scale bars are 200 nm (a, c) and 10 nm (c, d).
[0035] FIG. 6 shows an example high-resolution TEM image of a cross-link in a BN aerogel. The atomic layers of BN extend uninterrupted from all three aerogel sheets, showing that these extended structures are held together by covalent sp 2 bonds. Similar structures of varying geometries are found throughout the BN aerogel samples. Scale bar is 5 nm.
[0036] FIG. 7 shows (a) Example electron energy loss spectrum taken from a converted BN aerogel. The strong peak near 200 eV is attributed to boron, with edge features consistent with sp 2 -bonded BN; the peak near 400 eV is attributed to nitrogen. Noticeably absent is any distinguishable feature near 290 eV which would indicate the presence of carbon. The calculated ratio of boron to nitrogen is nearly 1:1, and the carbon concentration is below the resolution of the spectrometer (<5%). (b) Example Raman spectrum of the BN aerogel (solid line) and the graphene-based precursor (dotted line). The graphene aerogel spectrum shows broad peaks for the D and G bands in graphene, as observed in previous reports of graphene aerogel synthesis. The BN spectrum shows a single sharp peak at 1366 cm −1 , indicating that the BN aerogels have highly crystalline sp 2 bonding.
DETAILED DESCRIPTION
[0037] Reference will now be made in detail to some specific examples of the invention including the best modes contemplated by the inventors for carrying out the invention. Examples of these specific embodiments are illustrated in the accompanying drawings. While the invention is described in conjunction with these specific embodiments, it will be understood that it is not intended to limit the invention to the described embodiments. On the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.
[0038] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. Particular example embodiments of the present invention may be implemented without some or all of these specific details. In other instances, well known process operations have not been described in detail in order not to unnecessarily obscure the present invention.
[0039] Various techniques and mechanisms of the present invention will sometimes be described in singular form for clarity. However, it should be noted that some embodiments include multiple iterations of a technique or multiple instantiations of a mechanism unless noted otherwise.
[0040] An aerogel is typically defined as a porous, monolithic, solid material comprised of cross-linked elements or constituents, whose pores are filled with air or some other gas. Aerogels typically have extremely low densities (e.g., about 0.0011 grams per cubic centimeter (g/cm 3 ) to 0.5 g/cm 3 , or about 0.2 g/cm 3 ) and high specific surface areas (e.g., about 100 meters squared per gram (m 2 /g) to 3000 m 2 /g). An aerogel is typically open-porous (i.e., the gas in the aerogel is not trapped inside solid pockets) and may have pores or slits about 1 nanometer (nm) wide to 1 micron wide.
[0041] Disclosed herein are synthesis methods and the characterization of high specific surface area (SSA), low density BN aerogels that in some embodiments are comprised locally of few atomic-layer sheets of hexagonal BN. In some embodiments, the BN aerogels show a high degree of crystalline order and chemical purity. In some embodiments, the synthesis methods use only common, non-hazardous reactants. In some embodiments, carbon nanostructures can be substantially or completely converted to BN while maintaining their macro and meso-scale morphologies.
[0042] In some embodiments, BN aerogel synthesis methods are based on the carbothermal reduction of graphene aerogels to BN aerogels having a similar structure as the graphene aerogels. The graphene aerogels, with a typical mass density of about 60 mg/cm 3 to 150 mg/cm 3 , may be prepared using a number of different methods. In some embodiments, the graphene aerogels are placed together with boron oxide powder in a graphite crucible and heated in an induction furnace under nitrogen flow. At sufficiently high temperatures, the graphene sheets of the starting aerogel may be converted to hexagonal (hBN) nominally according to the following reaction:
[0000] B 2 O 3 +3C+N 2 →2BN+3CO (1)
[0043] The boron oxide is believed to react purely in the vapor phase, and BN is found to be the only solid product at temperatures above about 1500° C. in some embodiments. In practice, the operating temperature for this reaction is in the range of about 1600° C. to 1800° C. in order to provide sufficient vapor pressure of boron oxide. In some embodiments, contact between the aerogel and liquid boron oxide is avoided, so as to prevent any potential damage to the pore structure from capillary forces. The carbon and BN here are in their hexagonal phases; as such, reaction (1) represents an in-situ reforming of the sp 2 bonded layers of the starting material.
[0044] FIG. 1 shows an example of a method for synthesizing an aerogel comprising boron nitride. In operation 105 of a method 100 , boron oxide and an aerogel comprising carbon are provided. In some embodiments, the boron oxide and the aerogel comprising carbon are placed in a graphite crucible (e.g., about 10 grams of boron oxide in an about 2″ diameter by about 4″ tall cylindrical graphite crucible). In some embodiments, the aerogel is supported in the middle of the crucible by a graphite cup with holes drilled in the bottom to allow for flow of reactant gases.
[0045] The aerogel comprising carbon may be fabricated using many different techniques. For example, in some embodiments, graphene oxide powder (e.g., about 0.2 grams) is mixed with deionized water (e.g., about 16.7 mL) in a glass vial and sonicated to reach a smooth liquid consistency. Ammonium hydroxide (e.g., about 3.3 milliliters, about 28 weight percent solution) is added and mixed well. The vial is sealed and heated to about 85° C. for about 40 hours, which produces a monolithic hydrogel. The gel is then soaked sequentially in deionized water and high purity isopropanol alcohol. Solvent is removed by supercritical CO 2 drying in a critical point dryer. The aerogels are then graphitized via firing for about 3 hours at about 1100° C. under an argon gas flow. Further details regarding this process for fabricating a carbon aerogel can be found in U.S. patent application Ser. No. 13/204,277 and in the publication Worsley, M.; Pauzauskie, P.; Olson, T.; Biener, J.; Satcher, J.; Baumann, T. Synthesis of graphene aerogel with high electrical conductivity. J. Am. Chem. Soc. 2010, 132, 14067-14069, both of which are herein incorporated by reference in their entireties.
[0046] In operation 110 , the boron oxide is heated to melt the boron oxide and the aerogel is heated. For example, a crucible containing the boron oxide and the aerogel may be heated to melt and evaporate the boron oxide, and to heat the aerogel and any gases contained in the crucible. In some embodiments, the boron oxide and the aerogel are heated with a radio frequency induction furnace. In some embodiments, the boron oxide and the aerogel are heated to about 1600° C. to 1800° C.
[0047] In operation 115 , a nitrogen-containing gas is mixed with boron oxide vapor from molten boron oxide. In some embodiments, the nitrogen-containing gas comprises nitrogen. In some embodiments, the flow rate of the nitrogen-containing gas is about 1000 standard cubic centimeters per minute (sccm) to 2000 sccm, or about 1500 sccm. In some embodiments, the nitrogen-containing gas is introduced through a central tube of a cylindrical graphite crucible, which may aid in transporting boron oxide vapor upward towards the aerogel.
[0048] In operation 120 , at least a portion of the carbon of the aerogel is converted to boron nitride. In some embodiments, the conversion may be performed in about 30 minutes or less at a temperature greater than about 1600° C.; performing operation 120 in about 30 minutes or less may preserve the nanostructure of the aerogel during the conversion process. At 1600° C. to 1800° C. and using nitrogen as the nitrogen-containing gas at a flow rate of 1500 sccm, the evaporation rate of boron oxide is about 500 mg per minute. Further details regarding the method 100 may be found in U.S. Provisional Patent Application No. 61/751,641, which is herein incorporated by reference in its entirety.
[0049] After performing the method 100 , the aerogel comprises boron nitride. In some embodiments, the boron nitride has a substantially ordered crystalline structure. In some embodiments, the aerogel comprises at least about 95 atomic percent boron nitride. In some embodiments, the ordered crystalline structure includes atomic layers of hexagonal boron nitride lying on top of one another, with atoms contained in a first layer being superimposed on atoms contained in a second layer. For example, the atomic layers of hexagonal boron nitride may be stacked such that boron atoms of a first layer overlay nitrogen atoms of a second layer, and the nitrogen atoms of the first layer overlay boron atoms of the second layer. In some embodiments, the boron nitride comprises hexagonal boron nitride. In some embodiments, the boron nitride has a white color. In some embodiments, atomic planes of the boron nitride have an interplanar distance of about 3.3 Angstroms.
[0050] In some embodiments, the boron nitride does not have a substantially turbostratic crystalline structure (i.e., a type of crystal structure found in materials where atomic planes, such as those in graphite or BN, are inclined and rotated randomly with respect to one another). In some embodiments, the boron nitride does not have a substantially disordered crystalline structure.
[0051] In some embodiments, the aerogel comprises sheets of boron nitride that are covalently bonded to one another. In some embodiments, there is overlap between the sheets of boron nitride of the aerogel, which may increase the mechanical stability of the aerogel while maintaining a high specific surface area. In some embodiments, atomic planes of BN may be shared between neighboring sheets of BN, which may further increase the mechanical stability of the aerogel. When forming an aerogel comprising boron nitride using other processing techniques, and not the carbothermal reduction technique described herein, the aerogel may include small particles of boron nitride (e.g., typically boron nitride crystallites tens of atomic layers thick) that are weakly bound together with little or no overlap (i.e., few of no particles sharing an atomic plane of boron nitride) or covalent bonding between the particles of the aerogel.
[0052] In some embodiments, the aerogel comprises sheets of boron nitride, with the sheets of boron nitride including about 5 atomic layers of boron nitride or less. In some embodiments, the aerogel comprises sheets of boron nitride, with the sheets of boron nitride including an average of about 6 atomic layers of boron nitride. In some embodiments, the aerogel comprises crumpled sheets of boron nitride, with the sheets of boron nitride having a thickness and dimensions of about 10 microns to 50 microns by about 10 microns to 50 microns.
[0053] In some embodiments, the aerogel comprises sheets of boron nitride, with at least a portion of the sheets of boron nitride forming slit-shaped pore structures about 400 nanometers to 600 nanometers wide and about 2 microns to 4 microns long. In some embodiments, the aerogel comprises sheets of boron nitride, with at least a portion of the sheets of boron nitride forming slit-shaped pore structures about 500 nanometers wide and about 3 microns long.
[0054] In some embodiments, the aerogel has a specific surface area of about 350 meters squared per gram (m 2 /g) to 3000 m 2 /g. In some embodiments, the aerogel has a specific surface area of about 350 m 2 /g to 1050 m 2 /g. In some embodiments, the aerogel has a specific surface area of about 700 m 2 /g. In some embodiments, the aerogel has a specific surface area of about 1500 m 2 /g to 3000 m 2 /g. In some embodiments, the aerogel has a mass density of about 50 milligrams per cubic centimeter (mg/cm 3 ) to 150 mg/cm 3 . In some embodiments, the aerogel has a mass density of about 100 mg/cm 3 . In some embodiments, pores of the aerogel have a diameter of about 2 nanometers to 50 nanometers.
[0055] Potential applications of boron nitride aerogels include water purification, gas storage (including hydrogen and CO 2 ), oil recovery from oil spills, catalyst support, gas sensor, biosensor, fuel cell membranes, batteries, filters, poison control, and supercapacitors.
[0056] These and other features, together with the organization and manner of operation thereof, will become apparent from the following detailed description when taken in conjunction with the accompanying drawings.
[0057] Working Examples
[0058] The following description of the characterization of a BN aerogel synthesized using methods disclosed herein and of the reactions associated with BN aerogel synthesis methods are intended to be examples of the embodiments disclosed herein, and are not intended to be limiting.
EXAMPLE 1
Methods
[0059] Synthesis of Graphene Aerogels. Graphene oxide powder (Cheap Tubes Inc., 0.2 g) was mixed with deionized water (16.7 mL) in a 20 mL glass vial and sonicated to reach a smooth liquid consistency. Ammonium hydroxide (3.3 mL, 28 wt % solution) was added and mixed well. The vial was sealed and heated at 85° C. for 40 h, resulting in a monolithic hydrogel. The gel was then soaked sequentially in deionized water and high-purity isopropyl alcohol. Solvent was removed by supercritical CO 2 drying. The aerogels were then graphitized via firing for 3 h at 1100° C. under argon flow.
[0060] Conversion of Graphene Aerogels. The conversion occurred in a 5 cm diameter by 10 cm tall cylindrical graphite crucible. The aerogels were supported in the middle of the crucible by a graphite cup with holes drilled in the bottom to allow for proper flow of the reactant gases. About 10 g of boron oxide powder (Alfa Aesar A11707) was placed at the bottom of the crucible, which was then heated under nitrogen flow (1500 sccm) in a radio frequency induction furnace to between 1600° C. and 1800° C. The powder was premelt to eliminate adsorbed water to prevent overbubbling and damaging the sample. Nitrogen was introduced through a central tube which in turn mixed well with the boron oxide vapor and helped to carry it upward toward the aerogels. The conversion was run long enough to allow for all of the boron oxide to evaporate; under these conditions, the evaporation rate of boron oxide was between 200 and 500 mg/min.
[0061] Determination of Interlayer Spacing. Starting from a high-resolution TEM image, the grayscale values of the pixels along a line transecting the given fringes were plotted. For two to three fringes, the resulting curve was fitted to a set of Gaussians using a Levenberg-Marquardt algorithm. For four or more fringes, a discrete Fourier transform was taken using a fast Fourier transform (FFT) algorithm. The resulting spectrum displayed a distinct Fourier peak superimposed on a 1/f background. The quoted values and precision for interplanar spacing corresponded to the center and width of the peak, respectively.
[0062] Characterization. TEM images were collected on a JEOL JEM2010 microscope operating at 80 kV. Samples were prepared by suspending the materials in isopropyl alcohol via ultra-sonication and then drop-casting onto holey carbon grids; alternately, the grids were simply rubbed gently against a cleaved surface of the gel. EELS was performed using a Phillips CM200 TEM operating at 200 kV and equipped with a Gatan imaging filter. Raman spectra were collected on a Renishaw inVia spectrometer using a 633 nm excitation laser. Nitrogen adsorption isotherms were measured using a Micromeritics ASAP 2010 porosimeter. XRD was performed using a Bruker D8 Advance X-ray diffractometer using Cu Kα radiation.
EXAMPLE 2
Results
[0063] FIG. 2 shows an example of a photograph of a graphene aerogel. FIG. 3 shows an example of a photograph the graphene aerogel after conversion to a BN aerogel. The BN aerogel substantially maintained its original size and macroscopic shape. There was, however, a dramatic change in color from black to white, which was uniform throughout the cross-section of the sample. There was a small degree of mass loss due to the boron nitride conversion process (i.e., about 10%), which is consistent with other studies of carbothermal reduction of boron nitride.
[0064] Scanning electron microscopy showed that the meso-scale BN aerogel had a foliated architecture very similar to that of the starting graphene aerogel, as shown in FIG. 4 . Thin sheets several tens of microns on a side were found crumpled together, forming slit-shaped pore structures around 500 nanometer (nm) wide and several microns long. These structures were stable, despite being atomically thin, owing to the relatively high stiffness of few-layer BN sheets. Graphene and BN are unique in forming such structures; the mechanical properties of the sheets, coupled with the low atomic numbers of their constituent atoms, allows for the fabrication of crystalline, high SSA materials.
[0065] Transmission electron microscopy of graphene aerogels ( FIG. 5 a , 5 c ) and converted boron nitride aerogels ( FIG. 5 b , 5 d ) showed that the morphology on the 100 nm scale was not significantly altered upon conversion to BN. In both the graphene and the BN aerogels, the material was composed of wrinkled sheets with facets on the order of hundreds of nm 2 and several atomic layers thick. However, differences were apparent at higher magnifications ( FIG. 5 c , 5 d ). The intrinsic “sheets” of converted BN, while retaining roughly the same size and shape, were approximately twice as thick as those of the original graphene aerogel, increasing from 3 to 6 atomic layers on average. These thicker BN sheets were straighter and more ordered than those of the graphene aerogel; e.g., in some cases, atomically straight edges 40 nm and longer were observed, whereas such features were at most 10 nm in the graphene aerogel precursor.
[0066] FIG. 6 shows a high-magnification TEM image of a cross-link in a converted BN aerogel. The sheets here formed a “Y” junction, wherein neighboring sheets shared one or more atomic layers. Some layers extended fully from one sheet to the next, while others overlapped by several nanometers. Such junctions were found in regions of the sample where two sheets laid atop one another. The aerogel thus appeared to be an interlaminated structure, where shared, sp 2 -bonded layers of BN form the cross-links between the sheets.
[0067] The chemical composition and bonding structure of BN aerogels was analyzed via electron energy loss spectrum (EELS) taken over a probe area of about 50 nm radius, as shown in FIG. 7 a . A distinct nitrogen K edge at 401 eV, as well as the well-resolved boron peaks arising from π* and σ* states at around 188 eV, indicated a well-ordered, hexagonally bonded BN. The absence of any carbon K edge at 284 eV confirmed that the original graphene aerogel had been completely consumed in the conversion process. The boron to nitrogen atomic ratio for this sample was 0.97±0.14, while the carbon content was less than 5%.
[0068] The dramatic change in the chemical composition and crystalline order upon converting graphene aerogel to BN aerogel was also evident in the Raman spectra of the respective materials, as shown in FIG. 7 b . For the graphene aerogel, a strong D peak at 1329 cm −1 and the absence of a significant 2D signal (not shown) indicated a multilayer, disordered graphene structure, as observed previously for other graphene aerogels synthesized by a similar method. After subtraction of a background signal, the asymmetric G band was fit into two Lorentzians at 1573 cm −1 and 1601 cm −1 with full width at half maximum (FWHM) of 60.56 cm −1 and 26.74 cm −1 , respectively. This peak fitting was qualitatively similar to double-peak features found in graphene nanoribbons. After conversion to BN, these peaks were entirely absent and replaced by a single peak at 1366 cm −1 , as also observed in highly crystalline samples of pyrolytic h-BN. This E 2g peak was due to the same in-plane phonons that give rise to the G peak in graphene. There was no measurable shift in the peak, as is expected for BN sheets more than 5 atomic layers thick. The FWHM of 14 cm −1 indicated a highly crystalline BN and the small increase in peak width from 9.1 cm −1 was likely related to finite phonon lifetimes due to the nanoscale crystal grains within the wrinkled sheets of the aerogel. A quantitatively similar broadening of the E 2g peak has been seen previously in BN crystallites similar in size and shape to the aerogel platelets seen in the TEM images.
[0069] The increase in crystalline order, as well as the increase in the wall thickness compared to the graphene precursor, have also been seen in the conversion of other nanostructured carbon materials, and appear to be a consequence of the specifics of the conversion reaction. The doubling of the number of layers making up the BN aerogel was corroborated by an approximate halving of the SSA; for one particular sample, the mesopore surface area (2 nm to 50 nm pore diameter) derived from nitrogen adsorption isotherms and calculated using the Brunauer-Emmett-Teller (BET) model was reduced from 1390 m 2 /g for the graphene precursor to 675 m 2 /g for the BN aerogel. At the same time, the mass and consequently the density tended to decrease by around 10%. While Eq. (1) would imply a mass increase, it is possible that additional mass losses are introduced through impurity oxidizers as well as the formation of cyanogens.
[0070] The mass loss and SSA reduction, coupled with the observation that the nanoscale folds in the sheets are preserved, suggests a particular mechanism for the carbothermal reduction process. Namely, it seems likely that the BN conversion process proceeds via a face-to-face reaction of two graphitic surfaces. A possible intermediate step in reaction (1) is the inclusion of boron radicals in each of two adjacent graphene lattices (C n ) via a partially reduced boron oxide molecule, followed by nitridation:
[0000] B 2 O 2 +2C n →2B*C n−1 +2CO (2)
[0000] 2B*C n−1 +2N 2 →2BN+2C n−2 +C 2 N 2 (3)
[0071] It was observed (in separate experiments) that single-walled carbon nanotubes do not tend to survive the conversion process, whereas double-walled carbon nanotube do tend to survive the conversion process, which further supports this view.
[0072] The role of water, which is always present in the conversion system that was used (i.e., a cylindrical graphite crucible) because of the hygroscropic nature of the insulation in the furnace, should also be considered. It is known, for example, that the presence of water dramatically increases the formation of cyangens in the direct nitridation of graphite.
[0073] Further studies, in particular analysis of flue gases and the role of water concentration in the reactants, will help to clarify the details of the reduction process.
[0074] Finally, it should be noted that formation of BN via carbothermal reduction is typically surface-passivated, and thus conventionally additional promoters such as various metal oxides are necessary to obtain appreciable conversion yield. This is not the case for the methods disclosed herein. The exceptionally high SSA of graphene aerogels lends itself particularly well to the conversion process, and as such, no additional promoters are necessary to take the reaction to completion.
EXAMPLE 3
Conclusion
[0075] Disclosed herein are embodiments of an inexpensive and non-toxic process for the conversion of a porous crystalline graphene material to a similarly structured BN material, opening possibilities in the research and development of new nanostructured BN materials. The growing number of applications for porous BN demands new methods for synthesis. The processes disclosed herein show that the meso-scale architecture, as well as the nanoscale morphology of the porous precursor materials, can be well maintained through conversion to BN.
[0076] Further details regarding some of the example embodiments disclosed herein can be found in Rousseas et al., Synthesis of Highly Crystalline sp 2 -Bonded Boron Nitride Aerogels, ACS NANO, 2013, 7(10):8540-8546, which is herein incorporated by reference in its entirety.
[0077] As used herein, the singular terms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a marker can include multiple markers unless the context clearly dictates otherwise.
[0078] As used herein, the terms “substantially,” “substantial,” and “about” are used to describe and account for small variations. When used in conjunction with an event or circumstance, the terms can refer to instances in which the event or circumstance occurs precisely as well as instances in which the event or circumstance occurs to a close approximation. For example, the terms can refer to less than or equal to ±10%, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%.
[0079] Additionally, amounts, ratios, and other numerical values are sometimes presented herein in a range format. It is to be understood that such range format is used for convenience and brevity and should be understood flexibly to include numerical values explicitly specified as limits of a range, but also to include all individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly specified. For example, a ratio in the range of about 1 to about 200 should be understood to include the explicitly recited limits of about 1 and about 200, but also to include individual ratios such as about 2, about 3, and about 4, and sub-ranges such as about 10 to about 50, about 20 to about 100, and so forth.
[0080] In the foregoing description, it will be readily apparent to one skilled in the art that varying substitutions and modifications may be made to the invention disclosed herein without departing from the scope and spirit of the invention. The invention illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations, which is not specifically disclosed herein. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention. Thus, it should be understood that although the present invention has been illustrated by specific embodiments and optional features, modification and/or variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scopes of this invention.
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This disclosure provides methods and materials related to boron nitride aerogels. For example, one aspect relates to a method for making an aerogel comprising boron nitride, comprising: (a) providing boron oxide and an aerogel comprising carbon; (b) heating the boron oxide to melt the boron oxide and heating the aerogel; (c) mixing a nitrogen-containing gas with boron oxide vapor from molten boron oxide; and (d) converting at least a portion of the carbon to boron nitride to obtain the aerogel comprising boron nitride. Another aspect relates to a method for making an aerogel comprising boron nitride, comprising heating boron oxide and an aerogel comprising carbon under flow of a nitrogen-containing gas, wherein boron oxide vapor and the nitrogen-containing gas convert at least a portion of the carbon to boron nitride to obtain the aerogel comprising boron nitride.
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CROSS REFERENCE TO RELATED CASE
This application is a continuation-in-part of U.S. Ser. No. 935,168, filed Aug. 21, 1978 abandoned, herein incorporated by reference.
DESCRIPTION
BACKGROUND OF THE INVENTION
The present invention is concerned with aqueous dispersion coating compositions and in the application of said coating compositions to FRP (fiber reinforced plastics).
FRP is generally a mixture of resin compound and reinforcing fibers, principally glass fibers and is generally formed into a sheet molding compound (SMC) or a bulk molding compound (BMC). It is the SMC or BMC which is compression molded to form the desired part or substrate. FRP is described in British Pat. No. 1,457,935 and U.S. Pat. No. 4,081,578, which are hereby incorporated by reference.
U.S. Pat. No. 3,787,230 teaches the application of powder paint in an aqueous slurry applied to an article when the powder paint is substantially uniformly suspended.
Industry has been particularly interested in obtaining coating compositions that are environmentally safe and produce little or no emissions to the atmosphere. A particularly vexatious problem has been the application of coating compositions to FRP as SMC to produce a film which is substantially free of pin holes.
SUMMARY OF THE INVENTION
The present invention is concerned with aqueous dispersion coating composition consisting essentially of a particulate film forming epoxy composition with a pigment volume concentration (PVC) of at least 10 in a water carrier wherein the water carrier has dispersed therein a nonionic surfactant in an amount ranging from about 0.01 to about 10% by weight (hereinafter PBW) of the total coating composition; and an organic dispersing agent in an amount from about 0.01 to about 10 PBW. The coating composition is applied to FRP such as SMC.
DESCRIPTION OF PREFERRED EMBODIMENTS
The coating compositions of the present invention are applicable towards all nonwater soluble epoxy coating compositions. Suitable epoxy materials are epoxy resins obtained by reacting a dihydric phenol and a epihalohydrin. Suitable reactants include bis(4-hydroxy phenyl) dimethyl methane and epichlorohydrin. Other suitable dihydric phenols include resorcinol; 1,1-bis(4-hydroxy phenyl) ethane; 1,1-bis(4-hydroxy phenyl) propane; 1,1-bis(4-hydroxy phenyl) butane; 2,2-bis(4-hydroxy phenyl) butane; and 1,1-bis(4-hydroxy phenyl) 2 methyl propane. Typical epoxy resins are those having an epoxy equivalent of between about 650 and 1000. It is preferred that the epoxy material be a solid at ambient temperature and pressure. Illustrative commercial resins that are suitable in the practice of the invention include the following:
______________________________________ Epoxide Equivalent Durrans SofteningEpoxy Resin Weight (Approximate) Point (Approximate)______________________________________Epi-Rez 530 C 900 95-100° C.Epon 1004 900 100° C.Ciba Giegy 7014 770 94° C.______________________________________
It is to be appreciated that the phrase "epoxy" is meant to include those resins that contain the oxirane ring in the coating composition. It is preferred that the epoxy compound employed be polymeric and that it contain more than 1 epoxy group per molecule, that is, that it have an epoxy equivalent greater than 1. Higher molecular weight epoxy materials can be obtained by reacting the polyglycidyl ether described above with a polyphenol, such as bisphenol-A.
While the polyglycidyl ethers of polyphenols may be employed per se, it is frequently desirable to react a portion of the reactive sites (for example, hydroxyl or in some instances epoxy) with a modifying material to vary the film characteristics of the resin. For example, the polyepoxide can be esterified with carboxylic acid, especially fatty acid. Especially preferred are saturated fatty acids.
Another useful class of polyepoxide is produced from Novolak resins or similar polyphenol resins.
Also suitable are the similar polyglycidyl ethers of polyhydric alcohols which may be derived from such polyhydric alcohols as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,4-propylene glycol, 1,5-pentanediol, 1,2,6-hexanetriol, glycerol, bis(4-hydroxycyclohexyl)2,2-propane and the like. There can also be used polyglycidyl esters of polycarboxylic acids, which are produced by the reaction of epichlorohydrin or similar epoxy compounds with an aliphatic or aromatic polycarboxylic acid such as oxalic acid, succinic acid, glutaric acid, terephthalic acid, 2,6-naphthylene dicarboxylic acid, dimerized linolenic acid and the like. Examples are glycidyl adipate and glycidyl phthalate. Also useful are polyepoxides derived from the epoxidation of an olefinically unsaturated alicyclic compound. Included are diepoxides comprising in part one or more monoepoxides. These polyepoxides are nonphenolic and are obtained by the epoxidation of alicyclic olefins; for example, by oxygen and selected metal catalysts, by perbenzoic acids, by acetaldehyde monoperacetate, or by peracetic acid, and/or hydrogen peroxide. Among such polyepoxides are the epoxy alicyclic ethers and esters which are well known in the art.
A class of polyepoxides which may be employed is acrylic polymers containing epoxy groups. Preferably these acrylic polymers are polymers formed by copolymerizing an unsaturated epoxy-containing monomer, such as, for example, glycidyl acrylate or methacrylate, a hydroxyl-containing unsaturated monomer and at least one other unsaturated monomer.
Another class of epoxies are the cycloaliphatic epoxies whereby a saturated cycloaliphatic ring (e.g. 5 or 6 members) is fused to an oxirane ring, such as the bicyclo[4,1,0]-heptane-7-oxy or the bicyclo[3,1,0]-hexane-6-oxy.
The dispersion coating composition of the present invention can best be described as powder paint dispersion. By "dispersion" is meant that particulates within a range of about 1 to about 100 microns are present and uniformly dispersed in the water carrier. Fine particles are employed so that thin films (less than 4 mils) may be produced. If very large particles are used, then smooth thin films would not be obtained. By "powder paint" is meant a particulate that contains all of the components necessary for a paint composition and may be obtained by removing the solvent from a liquid paint, such as that containing a film former, cross-linking agent, pigments and the like, to obtain the solid paint particles, such as in accordance with U.S. Pat. No. 3,737,401, hereby incorporated by reference. Other methods such as spray dry, melt mix (extrusion) or ball mill may also be used to produce "powder paint".
The epoxy material may be solubilized with any organic solvent which can be properly operable within the processing parameters in forming the powder paint particles from the liquid paint as taught in U.S. Pat. No. 3,737,401. Suitable water soluble solvents are Cellosolve (trademark of Union Carbide for ethyl ether of ethylene glycol), methyl Cellosolve, ethyl Cellosolve, butyl Cellosolve and the alkyl esters thereof, such as acetates and the like, Carbitol (trademark of Union Carbide for the monoethyl ether of diethylene glycol), methyl Carbitol, butyl Carbitol, hexyl Carbitol, and other organic alcohols, esters, ketones and the like. Of the above enumerated solvents, methyl Cellosolve is preferred.
An important aspect to the coating composition of the present case is the utilization of pigments which give a high covering. It has been found desirable to employ pigments such as titanium dioxide, alkaline earth metal carbonates, sulfates, and silicates, and the like, for example, barium, calcium or magnesium sulfate, carbonate or silicate, clay, limestone, carbon black and other pigments, such as the chromates, dyes, coloring agents, mordants, fillers and the like, lithopone, which is a white pigment consisting of zinc sulfide and barium sulfate.
It is preferred that the pigment volume concentration (PVC) be at least about 10 and more preferably at least 25. By "PVC" is meant the volume of the pigment in the dried paint film, i.e., the volume of pigment divided by the total volume of the solids of the coating composition. The proper PVC is followed in order to get the proper rheology during baking or curing of the coating composition. The correct amount of PVC prevents the coating composition from flowing too much during cure. The correct amount of PVC allows control of the flowing of the composition.
It is preferred that the epoxy coating composition be a thermosetting coating composition wherein there is a cross-linking agent employed. While a variety of cross-linking agents may be employed, such as the melamine type, it is preferred that the cross-linking agent be an isocyanate and in particular a blocked isocyanate. Other cross-linking agents may be used, such as urea formaldehyde, phenol formaldehyde, benzoguanamine, amide-imide, polyamide, polybenzimidazole and the like. Suitable isocyanates that may be employed are the aromatic isocyanates, the aliphatic isocyanates, isophorone diisocyanates and the like. For a suitable listing of polyisocyanates attention may be directed towards U.S. Pat. No. 3,843,593 patent, such as those cited in Columns 7-9.
In addition, the organic polyisocyanate may be a prepolymer derived from a polyol including polyether glycol or polyester polyol, or simple polyols, such as glycols, for example, ethylene glycol and propylene glycol as well as other polyols, such as glycerol, trimethylolpropane, hexanetriol, pentaerythritol, and the like, as well as monoethers, such as diethylene glycol, tripropylene glycol, and the like, and the polyethers, that is, alkaline oxide condensates of the above. For a suitable recitation of such organic polyisocyanates, attention may be directed towards German patent application No. 2,531,906, which is hereby incorporated by reference.
A number of blocking agents may be used to produce the blocked isocyanate which could be used as the cross-linking agent in the present case. Such blocking agents as the phenol type, lactone type, active methylene type, alcohol type, mercaptan type, acid amide type, imide, the amine type, the urea type, carbamate type, oxime type, sulfate and the like. Most preferably, a ketoxime type is preferred, and even more preferably, a dialkyl ketoxime of from 1 to 4 carbon atoms per alkyl group. Most preferably, the blocked isocyanate is an isophorone diisocyanate blocked with an oxime available from Cargill under the trade name Powder Coating Curing Agent 2400. After the liquid paint (epoxy, and cross-linking agent and pigments), hereinafter called the base material, has been prepared, it may be injected into an agitated deionized water bath through an airless type nozzle such as a Spraying System Company Teejet Nozzle SS000067 (orifice diameter 0.023"-0.058 mm). The particle size range and distribution may be controlled by the viscosity, type of solvent and solids of the paint, as well as the size and position of the nozzle, the shape of the agitator and the speed of the agitator which is used to agitate the deionized water. The agitation is useful in order to produce the powder paint particles pursuant to U.S. Pat. No. 3,737,401. After the paint has been dispersed as droplets in the water, it is stirred to effect a transfer of solvents into the water from the droplets. The precipitated paint is separated from the solvent water mixture and rinsed in clear deionized water to remove the remaining solvents present. The powder is then separated from the liquid using conventional filtration techniques.
The wet powder paint may be dried and used as a powder to be inserted into the aqueous carrier containing the other components as described below or the wet powder may be dispersed in a water medium similar to that described below.
After the powder has been obtained or using the wet cake from the process described above, the final coating composition may be obtained. It has been found desirable to add a water soluble high boiling material which is a non-solvent for the epoxy resin. A preferred material is a glycol such as a diethylene glycol, a triethylene glycol, and the like, which is to prevent caking of the powder upon the loss of water at ambient temperatures. Thus, an aqueous powder dispersion splashed on the sides of containers may be reincorporated into the body of the material. The high boiling material is present in an amount of about 0.5 to about 15% by weight of the dry powder.
During the formulation of the aqueous coating composition, a nonionic water soluble surfactant is employed to enable the liquid portion of a material to wet the powder more readily. This is present generally in the range of about 0.1 PBW to about 10 PBW of the dry powder concentration. Suitable nonionic surfactants are sorbitan fatty acid esters, polyethoxylated sorbitol fatty acid esters, polyethoxylated fatty acid esters, polyethoxylated alcohol ethers, glycerol fatty acid esters, propylene glycol fatty acid esters, polyoxyethylene derivatives of castor oil, polyethoxylated alkyl phenyl ethers, alkyl esters of phosphoric acid, and polyethoxylated esters of phosphoric acid.
It is also deemed necessary to have a dispersing agent present in an amount from about 0.01 to about 10 PBW of the dry powder concentration. By "dispersing agent" is meant a water soluble material that is added to the powder paint water dispersion, that is attracted to the epoxy particulate in dispersion or suspension in the water carrier and by means of a charge prevents agglomeration of the particle. While Applicants do not wish to be bound to any theory, it is believed that the utilization of the dispersing agent forms a Helmholtz double layer around the epoxy particle and that in turn prevents agglomeration of the particles. Preferred dispersing agents are anionic polymeric type dispersing agents, such as Tamol (trademark of Rohm & Haas for an acrylic polymeric dispersing agent). Other anionic dispersing agents may be lecithin, water soluble salts of alkyl sulfates, salts of polyethoxylated alkyl ether sulfates, water soluble phosphates, such as tetrasodium pyrophosphate, trisodium polyphosphate and the like.
Optionally, it has been found desirable to add a defoamer to control the formation of bubbles. The presence of bubbles in the final product is unacceptable from the packaging standpoint as well as the possibility of interference with the continuity of the final film. The range of defoamer material employed generally is of the order of 0.5 to about 3 PBW based on the dry powder coating and this will vary with the surfactants described above. A suitable defoamer is a product by the name of Nalco 2341, trademark for a silica containing organic material.
The pH of the coating composition should be on the basic side, preferably from about 8 to 12, and even more preferably, from about 8.0 to about 9.5, most preferably, about 8.3. An amine or other basic compound is employed to insure the basic pH of the system. The amine is added in an amount generally in the range of about 0.1 to about 15 PBW depending upon the nature of the powder and the other surfactants that are employed. Suitable organic amines are those having a boiling point greater than 100° C., such as dimethylethanol amine, dipropanol amine and the like.
It has been found desirable to add thickeners in an amount of about from 0.1 to about 10 PBW of the dry powder depending upon the powder solids concentration of the final dispersion, the nature of the powder and the particle size distribution of the powder in the final product. The concentration can be adjusted to give the desired flow as required. In addition, the thickener may act as an antisettling agent. Such thickeners may be water solubilized polyacrylic acids, polyurethanes, cellulosics or other highly polymeric materials or gel forming materials as modified Bentonite clays and the like.
It has been advantageous to hold the addition of a material used to adjust the pH until the last and a dispersing agent next to last in order to mix the other components thoroughly before activation of the bodying agents.
After the liquid portion of the final coating composition is prepared, the powder cake or dry powder is added under agitation. As with most incorporation of solids into liquids, the addition must be adjusted to the rate at which the powder is wet out to avoid an unmanageable agglomeration.
Agitation is continued until the mixture becomes relatively smooth and fluid. Care must be exercised to avoid increasing the temperature of the mixture to a point leading to instability of the dispersion. This temperature varies, but for the material described herein, it is about 100° F.
An aqueous powder dispersion such as that described herein has been further ground using either an Attritor (trademark of the Attritor Company for a piece of equipment which provides for fast, fine grinding) or a shotmill. In the laboratory, a water cooled stainless steel beaker, four millimeter glass beads and a steel disc attached to a shaft of a high speed agitator, has been used for further grinding. The specific material performs well at either a grind of 41/2 or 61/2 Hegeman (ASTM D1210-64) since in normal use, there is a primer that is applied over it prior to top coat application.
The aqueous powder dispersion described herein may be applied by any conventional technique, such as dipping, spraying and the like, although spraying is preferred.
The coating composition of the present invention is preferably applied to SMC, which is an abbreviation for sheet molding compound. SMC, when molded, is a very firm plastic material which has among its components fiberglass reinforcement and a thermosetting polyester. The polyester may be prepared by reacting phthalic anhydride (2 parts), maleic anhydride (1 part) and dipropylene glycol (10% excess). The polyester resulting from the former reaction is diluted with styrene, vinyl toluene or diallyl phthalate on a ratio of 1:2 parts of the polyester per part of the unsaturated compound. The composition is polymerized with an appropriate catalyst such as a peroxide.
The polymerized material then has about 30% by weight of fiberglass added thereto. This composition is then molded and cured under high pressure at about 350° F. It has also been found desirable to add filler components such as asbestos, sisal, talc, calcium carbonate, Barytes (barium sulfate), hollow glass spheres, carbon and the like.
During the molding and curing of the FRP or SMC material, gas is trapped between the pockets of the formed plastic. Previously when top coat coating compositions were applied and baked, a gaseous problem occurred for the gas within the pockets was released at the high curing temperature of the prior art coating composition. Also, distorted shapes were obtained as a result of the high cure temperature.
Now, however, due to the curing process described further below of the coating composition of the present case, gasing is substantially eliminated for SMC materials and pin holes in the top coat are substantially eliminated.
The process for curing the coating composition in the present application is performed when SMC is a substrate by applying the coating composition normally at ambient temperature, flashing off the water at a temperature of about 100° F. to 212° F. (100° C.), preferably at 125° F., for a short period of time, generally ranging from about 1 to about 20 minutes, and then raising the temperature to curing normally at a temperature range of about 300° F. (148.9° C.) to about 400° F. (204.4° C.) for a period of time of about 1 to about 30 minutes. It has been possible to cure the coating at a temperature as low as 250° F. (121.1° C.) for 15 minutes using a curing agent for epoxy materials supplied by Ciba Geigy identified as XU232 which is a solid powder at ambient temperature and is an adduct of an amine and a glycidyl ether. After the water has been flashed in the preliminary heating step, the powder components are present on the SMC as particulates. The film formed by the powder has not begun to flow because the temperature is sufficiently low thereby resulting in what is, in essence, a non-continuous coating of the paint particles. When the temperature is increased, the air that may be trapped in the SMC substrate may escape. As the curing of the coating composition occurs, the epoxy powder flows out into a continuous film from the non-continuous film in which the epoxy material was previously. As the curing temperature is reached, a continuous film of epoxy based coating covers the SMC substrate.
The sheet molding compound that may be employed is both regular and low density and may contain glass spheres or fibers. The thickness of the aqueous coating composition in the wet state is about 1 to about 10 mils, preferably about 4 mils. The prebaking temperature is 120° F. for about 10 minutes.
After curing, the part may be coated with either a sheet metal primer, which is preferred, or a coating material as is usually used as a top coat for industrial objects. Any well known primer or top coat can be used.
EXAMPLE
A coating composition was prepared from a base material described below formulated from the following components:
______________________________________Component PBW______________________________________Carbon Black 0.25Titanium Dioxide 5.13Lithopone 12.29Clay 12.29Talc 4.19Epoxy Resin (Ciba Geigy 7014) 18.53Methyl Cellosolve 40.12Blocked Isocyanate (Cargill 2400) 4.66Methylethyl Ketone 2.31Modaflow (trademark of Monsanto for 0.23polyacrylic flow control agent) 100.00______________________________________
This composition was ground to a 5 Hegeman reading.
The coating composition described above was formulated from the liquid paint state to a dry particulate by adding 17200 PBW of the above composition to 335000 PBW of deionized water by spraying the liquid paint under the surface of the deionized water onto a rotating Shar blender saw tooth blade where the orifice of the nozzle from which the liquid paint is spraying is 0.023 inches. The blade was rotating at 4700 linear ft./min. The time for passing the liquid paint through the orifice was about 4 minutes at a rate of speed of 1 gal./min. The particles produced were fine, gritty materials which were filtered from the water by means of a vacuum filter, reintroduced into another bath containing an equal quantity of deionized water in order to remove additional solvents and those particles again are filtered by means of moving belt vacuum filter. The powder cake having 44% nonvolatiles was then treated below.
The final coating dispersion composition was prepared from the following components:
______________________________________Components PBW______________________________________Dry Base Computed From Solids Runon Above Cake 35.25Deionized Water 60.22Diethylene Glycol 1.76Tergitol TMN-6 (trademark of Union Carbide 0.05for a nonionic surfactant, liquid atambient temperature containing trimethylnonyl polyethylene glycol ether obtainedby reacting trimethyl nonanol and 6 molesof ethylene oxide with a calculatedHLB# of 11.7) (90% Concentration)BORSCH GEL L75 (trademark of BORCHERS A.G. 0.35for a urethane thickener)Defoamer (NALCO 2341) 0.04Polyacrylic Acid Thickener 0.71Dimethylethanol Amine 0.21Dispersing Agent Tamol 731 (25% concentration) 1.41______________________________________
The coating composition in dispersed state (having 35% pigment:volume) as described above was sprayed by means of a conventional air sprayer onto sheet molding compound prepared as described above. The coating composition was uniformly dispersed and the film in the wet state as applied to SMC was 4 mils thick. The substrate was then subjected to a surface temperature of about 120° F. for 10 minutes which flashed off the water. Curing of the film occurred at about 350° F. for 20 minutes. Thereafter, the cured film had a hard finish, having a 2H pencil hardness. The cured film was subjected to a cross hatch adhesion test and 100% of the film was retained by the substrate.
An epoxy ester solvent type primer was then applied to the cured film and baked for 20 minutes at 325° F. (162.8° C.) and top coated with a nonaqueous dispersion of commercially available thermoset acrylic paint. The thus coated substrate was treated to an immersion and soap spot test without failure.
It is to be appreciated that the aqueous dispersion may also contain an effective conducting amount of a conductive filler to make the coating composition conductive. Suitable conductive fillers are graphite, carbon black, ferrophos, metallic pigments, as aluminum, zinc, and the like. The coating is made conductive so that the coated SMC would be conductive. This allows the use of electrostatic spraying techniques in subsequent applications of primer and top coat.
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PCT No. PCT/US79/00526 Sec. 371 Date July 23, 1979 Sec. 102(e) Date July 23, 1979 PCT Filed July 23, 1979 PCT Pub. No. WO81/00096 PCT Pub. Date Jan. 22, 1981
Described is an aqueous dispersion coating composition consisting essentially of an epoxy powder paint and a water carrier wherein the water has dissolved therein a water soluble nonionic surfactant in an amount ranging from about 0.01 to about 10% by weight (PBW) of the dry epoxy material and a dispersing agent in an amount from about 0.01 to 10 PBW of the dry epoxy material, wherein the pigment volume concentration of the coating composition is at least 10. Also described is a method of coating formed fiber reinforced plastics, such as sheet molding compound.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to a multispectral laser printing system and, more particularly, to a multispectral laser printing system employing efficient optical elements.
2. Background of the Prior Art
Multispectral laser printing systems are well known in the art as evidenced by U.S. Pat. No. 3,975,748, entitled "Multispectral Laser Camera Device", issued Aug. 17, 1976. The aforementioned patent shows a laser printing system embodying a helium neon laser to provide a red wavelength band and an argon laser to provide a multispectral wavelength band having green and blue wavelength components. The multispectral wavelength band is thereafter separated by a beam splitter into its blue and green wavelength components by a plurality of dichroic mirrors which operate to separate the different wavelengths of light in order to enable each wavelength of light to be individually modulated. The modulated red, green and blue wavelength beams are thereafter recombined by another plurality of dichroic mirrors back into a single multispectral wavelength beam which is thereafter directed to line scan photosensitive material in order to record the desired color image. The dichroic mirrors which are utilized both as beam splitters and beam recombiners are generally in the order of 50 percent efficient thus resulting in a 50 percent loss of beam energy each time a multispectral wavelength beam is split or each time two different wavelength beams are recombined into a multispectral wavelength beam. Thus, there is a substantial loss in beam energy as a result of the use of such beam splitters resulting in a substantial reduction in the overall efficiency of the laser printing apparatus.
Therefore, it is a primary object of this invention to provide a multispectral laser printing system in which the high energy losses attributable to beam splitters is eliminated.
It is a further object of this invention to provide a multispectral laser printing system of high efficiency in which beam splitting and beam recombination are accomplished by highly efficient light refracting optical elements.
Other objects of the invention will in part be obvious and will in part appear hereinafter. The invention accordingly comprises the mechanism and system possessing the construction, combination of elements and arrangement of parts which are exemplified in the following detailed disclosure.
SUMMARY OF THE INVENTION
A multispectral laser printing apparatus of the type in which at least two laser beams of different spectral characteristics are provided also includes means for photomodulating each laser beam in response to an electrical signal representative of that spectral characteristic of the image to be printed. The laser printing apparatus also includes means for line scanning a photosensitive material with the modulated laser beams in order to print the image onto the photosensitive material. Means are also provided for recombining the modulated laser beams into a single multispectral beam. Such means includes at least one light refracting optical element structured and situated to effect a recombination of the modulated laser beams into the single multispectral beam which is thereafter directed to the means for line scanning the photosensitive material.
The multispectral laser printing apparatus may include another light refracting optical element structured and positioned to receive a single laser beam and to refract the received laser beam to provide at least the two laser beams therefrom. Alternatively, the one refracting optical element could be structured and arranged to receive a single laser beam and to refract the received laser beam to provide at least the two laser beams therefrom. The light refracting element may comprise either a prism or a defraction grating.
DESCRIPTION OF THE DRAWINGS
The novel features that are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation together with other objects and advantages thereof will be best understood from the following description of the illustrated embodiment or when read in connection with the accompanying drawings wherein like numbers have been employed in different FIGS. to denote the same parts and wherein:
FIG. 1 is a schematic diagram of the multispectral laser printing system of this invention;
FIG. 2 is a side view of a prism utilized in the system of FIG. 1; and,
FIG. 3 is a schematic diagram of an alternate embodiment for the multispectral laser printing system of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1 there is shown generally at 10 a schematic diagram for the multispectral laser printing system of this invention wherein the radiant energy source comprises a helium neon laser 12 which emits radiant energy having a red spectral characteristic and an argon ion laser 14 which emits radiant energy having both a green spectral characteristic and a blue spectral characteristic. The radiant energy emitted by both the argon ion laser 14 and the helium neon laser 12 is plane polarized in order to effectively optimize the transmission efficiency of the radiant energy through the refracting optical elements of this invention which are characterized by prisms 16 and 36 in FIG. 1.
The optical prism 16 operates to separate the multispectral radiant energy received from the argon ion laser 14 into predominantly green and blue wavelengths which are reflected respectively by mirrors 18 and 20 to photomodulators 24 and 26. The predominantly red wavelength beam from the helium neon laser 12 is reflected by a mirror 22 to a photomodulator 28. Photomodulators 24, 26 and 28 are well known in the art and operate to modulate the intensity of the beam of radiation passing therethrough in accordance with electrical signals applied respectively to the photomodulators. The electrical signals define the individual color components of the image to be recorded by the laser printing system of this invention in a manner well known to the art. The modulated green, blue and red wavelength beams emanating from the photomodulators 24, 26, 28, respectively, are thereafter reflected by mirrors 30, 32 and 34, respectively, for recombination by the prism 36. The single multispectral wavelength beam emanating from the prism 36 is thereafter directed to a beam expander 38 which operates to increase the beam diameter in a well-known manner in order to accommodate the focusing of a smaller dot during the actual line scanning operation of the photosensitive material. The expanded multispectral wavelength beam is thereafter reflected by mirrors 42 and 44 into a printer 46 which operates to line scan the focused multispectral wavelength beam in a well-known manner to expose a photosensitive material. The printer 46 may embody horizontal and vertical beam deflectors to achieve a two-dimensional line scan across a fixed photosensitive material in a manner as is disclosed in U.S. Pat. No. 3,506,779, entitled "Laser Beam Typesetter", issued Apr. 14, 1970, and now incorporated by reference herein. Alternatively, the printer 46 may include only a horizontal beam deflector to achieve a horizontal line scan of the multispectral wavelength beam while the film is incrementally advanced in the vertical direction in a manner well known to the art.
As is readily apparent, the prisms 16 and 36 replace beam splitters as was heretofore utilized, i.e., U.S. Pat. No. 3,975,748, supra, thereby minimizing the attendant inefficiencies associated with such beam splitters which are generally only in the order of 50 percent efficient. Prisms having suitable dispersion angles for use in the multispectral laser printing system of this invention preferably comprise a grade A fine annealed glass having a high refractive index together with a low Abbe factor and a low stress birefringency. One such glass is sold under the tradename LaSf-9. It has an index of refraction of 1.8449 and a low Abbe factor as well as suitable thermal properties. Another such suitable material is sold under the tradename Cvd Clearatron.
Referring now to FIG. 2 there is shown at 48 a prism made from LaSf-9 Grade A fine annealed glass and optimized to provide acceptable dispersion angles with minimum reflection losses at the prism surfaces. Optimized dispersion angles of 1.82 degrees are provided between the blue wavelength beam and the green wavelength beam and 3.24 degrees between the green wavelength beam and the red wavelength beam with total uncoated reflection losses of 9 percent for the blue wavelength beam, 6 percent for the green wavelength beam and 4 percent for the red wavelength beam assuming an incident multispectral beam of plane polarized light. In addition, the apex of the prism is configured to define an angle of 60.6 degrees and the prism is oriented relative to the incident multispectral wavelength beam to define an angle of incidence of 23 degrees.
Referring now to FIG. 3 where like numerals depict the aforementioned elements there is shown an alternate arrangement for the multispectral laser printing system of this invention embodying a single prism 48 for accomplishing both beam separation and recombination in the aforementioned manner. The helium neon laser 12 thus provides the red wavelength beam to the optical modulator 28 after which the red wavelength beam is reflected by a mirror 56 for transmission and refraction by the prism 48. The red wavelength beam emanating from the prism 48 is thereafter reflected by a corner cube 50 in a manner as is well known in the art back to the prism 48 for recombination in a multispectral wavelength band as shown at 57. Corner cubes are well known in the art and operate to reflect a beam of light in a direction parallel to the incident beam of light regardless of the angle of incidence at which the incident beam strikes the corner cube. The argon laser 14 emits a blue and green wavelength beam which is subsequently reflected by a mirror 60 for transmission and refraction by the prism 48 into a green wavelength beam and a blue wavelength beam. The green and blue wavelength beams are subsequently modulated by the photomodulators 24 and 26 respectively. The modulated green and blue wavelength beams are thereafter reflected respectively by corner cubes 52 and 54 back for recombination by the prism 48 into the multispectral wavelength beam 57. The multispectral wavelength beam, in turn, is reflected by a mirror 58 to the beam expander 38 from which it is directed to the printer 46 in the aforementioned manner.
As is readily apparent, the prism 48 operates to separate the multispectral wavelength beam from the argon laser 14 into blue and green wavelength beams which are subsequently modulated and reflected back to the prism 48 for recombination with the red wavelength beam to provide the multispectral wavelength beam 57 to the printer 46. In this manner, beam separation and recombination are accomplished by the same single light transmitting and refracting prism 48.
The refractive index temperature coefficient for the aforementioned LaSf-9 glass is approximately 10 -6 thereby in turn affecting at 3.6×10 -6 degree/C° angle shift. Although such an angular shift is small, the arrangement of FIG. 3 provides for temperature compensation since all three wavelengths are shifted with temperature during the first beam dispersion and thereafter shift in an equal but opposite direction during the subsequent beam recombination thus canceling out any temperature shift in the recombined multispectral wavelength beam 57.
Although a light transmitting and refracting prism has been shown and depicted as the light refracting optical element, it would also be possible to utilize light defraction gratings in place of the prisms. In addition, whereas the sources of radiant energy were described as providing laser beams preferably in the red, green and blue spectral regions, the invention is not so limited and the wavelengths of the radiant source could be selected to be anywhere between or within the far infrared and the ultraviolet portion of the spectrum where laser energy can be generated. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
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A multispectral laser printing system in which beam splitting and beam recombination are accomplished by light refracting optical elements instead of beam splitters in order to materially improve efficiency. In one embodiment such beam splitting and recombination can be achieved by a single light refracting optical element such as a prism.
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STATEMENT OF RELATED CASES
[0001] This case claims priority of U.S. Provisional Patent Application 60/690,881, filed Jun. 15, 2005, which is incorporated by reference herein.
FIELD OF THE INVENTION
[0002] The present invention relates to velocity measurement systems.
BACKGROUND OF THE INVENTION
[0003] There are a number of benefits to being able to accurately estimate the velocity of a sea-faring vessel. One is that an accurate estimation of velocity results in improved estimates of ship's position (when those estimates are velocity-based) for submerged vehicles (e.g., submarines, AUVs, UUVs, etc.). This is particularly important for submerged vehicles for which Global Positioning System (GPS) fixes are not available or otherwise kept to a minimum to maintain ship's covertness. Another benefit is that it improves the accuracy of certain on-board missile-delivery systems that employ a technique to obtain a velocity fix, which is then provided as initialization data to the missile before launch (i.e., it reduces missile Circular Error Probable (CEP)).
[0004] It is known to apply signal correlation to SONAR technology to measure velocity. See, for example, U.S. Pat. No. 4,244,026 to Dickey and U.S. Pat. No. 5,315,562 to Bradley et al. These systems typically include a sonar source and multiple receivers (i.e., hydrophones), which have a known separation. The SONAR source directs sonic pulses towards the ocean floor, and the receivers detect echoes of those pulses. The velocity of the vessel is then calculated based upon the distance traveled by the vessel between the transmission and reception of a first pulse and a second pulse.
[0005] As discussed further below, correlation SONARS rely on selecting a best or maximum “correlation” either between hydrophones or pulses, for the determination of velocity. Maximum correlation occurs when the ray path of an initial SONAR transmission (from the transmitter to the ocean floor, etc., and back to a receiver) of a first detected pulse is equal to the ray path of a second SONAR transmission.
[0006] Correlation SONAR systems can be water or ground referenced, and Spatial or Temporal based. A water-referenced correlation SONAR uses echoes reflected from the water beneath a vessel, whereas a ground-referenced correlation SONAR uses echoes reflected from the ocean bottom. A correlation sonar can also be both ground and water based in the sense of having both ground- and water-referenced modes of operation.
[0007] Spatial correlation SONAR calculates the velocity of a vessel by transmitting two or more pulses towards the ocean bottom, detecting echoes of the pulses on a planar two-dimensional array of hydrophones, determining which two hydrophones in the array correlate the best, and dividing the distance between those hydrophones by twice the time differential between the pulses. Peak correlation might take place between hydrophones, in which case an interpolation scheme is used. A Temporal correlation SONAR determines velocity by transmitting multiple pulses toward the ocean bottom and detecting echoes of the pulses at a hydrophone array. For a given pair of hydrophones, the system determines which two pulses correlate the best, and calculates velocity by dividing the fixed distance between the hydrophones by twice the time differential between the two correlated pulses.
[0008] Velocity estimates from correlation SONAR are subject to a variety of different random errors and bias errors. To the extent that these types of errors can be reduced, the accuracy of the velocity estimates will improve. Correlation SONARS also have integrity issues in which serious performance degradation can occur in the event that there is an undetected failure in a hydrophone or hydrophone channel and the SONAR uses the faulty channel data for its velocity solution. The phrase “hydrophone channel” means the hydrophone itself, as well as the connectors and cabling to channel electronics, the electronics, and associated data-processing components.
SUMMARY OF THE INVENTION
[0009] The present invention provides a way to improve the accuracy of velocity estimates from correlation SONAR. The improvement in accuracy is due to a reduction in bias and random error. The present invention also provides a means for detecting failures in a hydrophone or a hydrophone channel and thereby improves the integrity of a SONAR system.
[0010] In prior-art correlation SONARs, receiver (i.e., hydrophone) pairings for each of the possible ship's velocity vectors are established. Redundant receiver pairs are not, however, considered. In this context, a “redundant” receiver pair is a pairing of hydrophones in the actual receiver array that has the same spacing and orientation as a different pairing of hydrophones in the array. Since the two pairs have the same spacing and orientation, they are indicative of the same ship's velocity vector. And since the are indicate of the same ship's velocity vector, only one of those receiver pairs, a “primary pairing,” has traditionally been used for the velocity estimate.
[0011] The inventors recognized that there is an advantage to considering redundant receiver pairs for the velocity calculation. That is, even if a redundant pairing represents the same ship's velocity vector as a primary pairing, there are physical differences between the hydrophone channels that will result in differences in the velocity estimates that are generated from them. In other words, when redundant pairs are considered, there is a reduction in bias and random error in the velocity estimate.
[0012] Therefore, in accordance with the illustrative embodiment of present invention, one or more additional velocity estimates are generated using one or more sets of “redundant” receiver pairs. From the multiple velocity estimates, a single improved velocity solution is obtained using (e.g., straight averaging, weighted averaging, etc.) all of the velocity estimates.
[0013] The benefit of generating additional velocity estimates using the same pulses but different hydrophones lies in the degree of independence of the estimates. In particular, when using the same pulses but different hydrophones, there are:
Differences in the amplitude, phase responses, acoustic center drift, and beam patterns of hydrophones (sources of random and bias errors). Differences in physical location and orientation of individual hydrophones, as well as array flexure and vibration issues (major sources of bias errors). Uncalibrated outboard effects between hydrophone channels, such as those involving cabling, connectorization, and channel integrity issues that affect echo signal and/or noise (sources of random and bias errors). Ambient noise differences in the ocean and in the vicinity of the ship (the noise field) as well as in the different hydrophone channel electronics (a source of random errors).
[0018] A method for a velocity-measuring correlation SONAR in accordance with the illustrative embodiment of the present invention comprises selecting redundant receiver pairs having velocity vectors that are the same as primary receiver pairs upon which a first velocity estimate has been based and then estimating velocity based on said redundant receiver pairs, thereby developing a second velocity estimate.
[0019] A velocity-measuring correlation SONAR in accordance with the illustrative embodiment of the present invention comprises a receiver array, wherein said receiver array comprises a plurality of hydrophones; means for developing a first velocity estimate, wherein said first velocity estimate is based on a primary pair of said hydrophones having a first velocity vector; and means for developing a second velocity estimate, wherein said second velocity estimate is based on a redundant pair of said hydrophones having a second velocity vector, wherein said second velocity vector is equal to said first velocity vector.
[0020] The illustrative embodiment depicts the invention being applied to Spatial SONAR correlation; however, it is applicable to Temporal correlation sonar, as well.
[0021] In some variations of the illustrative embodiment, in addition to or instead of developing additional velocity estimates, the inventive method is used for SONAR fault detection and exclusion to improve correlation SONAR reliability and integrity. Specifically, if the difference between the two (or more) velocity solutions exceeds a threshold, a problem is indicated.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 depicts, figuratively, a first example of a prior-art, velocity-measuring, Spatial correlation SONAR system.
[0023] FIG. 2 depicts a prior art method for velocity-measuring, Spatial correlation SONAR.
[0024] FIG. 3 depicts a method for a velocity-measuring, Spatial correlation SONAR in accordance with the illustrative embodiment of the present invention.
[0025] FIG. 4 depicts a first comparative example in the prior art wherein the method of FIG. 2 is applied to the receiver array of FIG. 1 .
[0026] FIG. 5 depicts a second example, wherein the method of FIG. 3 is applied to the scenario described in the first comparative example.
[0027] FIG. 6 depicts a second comparative example in the prior art wherein the method of FIG. 2 is applied to the receiver array of FIG. 1 .
[0028] FIG. 7 depicts a fourth example, wherein the method of FIG. 3 is applied to the scenario described in the second comparative example.
DETAILED DESCRIPTION
[0029] FIG. 1 depicts a schematic of a prior-art velocity-measuring correlation SONAR system. SONAR system 100 , which may be mounted on the underside of a ship, comprises transmitter 102 and receiver array 104 . Receiver array 104 comprises receivers or hydrophones 1 through 16 (the terms “receiver” and “hydrophone” are used interchangeably herein).
[0030] The particular arrangement depicted as array 104 is the Trident SSBN Navigation Sonar System sixteen-hydrophone box array. In this array, receivers 12 , 11 , and 10 are not normally used. That is, in the prior art, they are used only if there is a failure in other receivers in the array. As used in this Specification, the term “back-up,” as applied to hydrophones, means hydrophones that are normally not used. On the other hand, receivers 1 - 9 and 13 - 16 are normally active. As used in this Specification, the term “prime,” as applied to hydrophones, means hydrophones that are normally active.
[0031] FIG. 2 depicts prior-art method 200 for velocity-measuring, Spatial correlation SONAR.
[0032] In accordance with operation 202 of prior-art method 200 , a series of pulses are transmitted vertically towards the ocean bottom. In operation 204 , echoes are detected at each prime hydrophone 1 - 9 and 13 - 16 . For a ground-referenced correlation SONAR, the echoes are returned from the ocean floor. For a water-referenced correlation SONAR, the echoes are returned from the water volume beneath the ship.
[0033] At operation 206 , pulse echo data is amplified, converted to digital, and then digitally filtered to yield in-phase (“I”) and quadrature (“Q”) data for each hydrophone channel. This I and Q data contains all of the amplitude and phase information contained in the echo pulses, but is base banded and thus vastly reduced in data rate from the A/D converted echo signals.
[0034] In accordance with operation 208 , a pulse location algorithm is employed to define the leading edge of each pulse.
[0035] At operation 210 , a pair of prime hydrophones is identified for each of the various possible ships' velocity vectors, given the arrangement of receiver array 104 . Redundant channels—those that have the same velocity (speed and direction) as an identified pair—are not used. For example, if ( 1 , 16 ) is identified as a receiver pair, then the following pairs would be considered redundant: ( 16 , 15 ); ( 15 , 14 ); ( 14 , 13 ); ( 5 , 6 ); ( 6 , 7 ); ( 7 , 8 ); and ( 8 , 9 ). Furthermore, no pairing is made for any back-up hydrophone, such as hydrophones 10 - 12 . A channel-selection pair array, which includes all of the possible non-redundant ship's velocity vectors, is created.
[0036] As per operation 212 , I and Q data from a first echo pulse in a reference channel is correlated with I and Q data from a later echo pulse for each of the other channels. These calculations will form a measured correlation function.
[0037] At operation 214 , the receiver pair having the best correlation (“the best-correlated receiver pair”) is identified.
[0038] In accordance with operation 216 , in the channel-selection pair array, a 3×3 array of receivers is formed, wherein the array is centered about the best-correlated receiver pair. A search for the peak of the correlation function is performed, which is likely to lie somewhere between the best-correlated receiver pair and another receiver pair in the 3×3 array.
[0039] The correlation function is a relationship between the correlation between receiver pairs and their displacement in the x and y directions, where “x” and “y” are fore/aft and athwart ships', respectively. If the peak does lie between receiver pairs, the location of the peak uses an interpolation algorithm to define different spacing and orientation between the receivers. The interpolation provides “correlation distances” in the forward and athwart ship's directions. The velocity is determined in operation 218 by dividing the correlation distances by twice the time differential between the pulses.
[0040] In accordance with the illustrative embodiment of present invention, one or more additional substantially independent velocity estimates are obtained by selecting “redundant” receiver pairs that have the same velocity vectors (i.e., speed and direction) as the “primary” receiver pairs. The velocity calculations are then repeated using this redundant receiver pair as the basis.
[0041] As used in this specification, the term “primary,” when used to refer to hydrophone pairs, means a first group of hydrophone pairs that are used to develop the first velocity estimate. The term “redundant,” when used to refer to hydrophones pairs, means a second group of hydrophone pairs that have the same velocity vectors as the primary hydrophone pairs and are used to develop a second, third, etc. velocity estimate.
[0042] FIG. 3 depicts method 300 for velocity-measuring, Spatial correlation SONAR in accordance with the illustrative embodiment of the present invention. Operation 302 comprises the operations of method 200 (i.e., the prior art). In operation 304 , a first set of redundant receiver pairs is designated, wherein those first redundant receiver pairs have the same velocity vectors as the primary receiver pairs, as identified in operation 302 .
[0043] In operation 306 , a revised channel-selection pair array is developed (see, operation 210 ). In some embodiments, each position in this new array employs a different pair of hydrophones than was used in the original channel selection array. In other words, in such embodiments, the channel-selection pair array includes only redundant receiver pairs.
[0044] In accordance with operation 308 , the peak of the correlation function is identified (see, operation 216 ) and the velocity based on the redundant receiver pairs is determined in operation 310 (see, operation 218 ).
[0045] If additional velocity estimates are desired, operation 304 is repeated, designating further sets of redundant receiver pairs, as available, that have the same velocity vector as primary receiver pairs. Operations 306 through 310 are repeated to develop each additional velocity estimate.
[0046] In operation 312 , an overall velocity solution that is a function of the two or more velocity estimates is developed. In some embodiments, the overall solution is arrived at by simply averaging the individual velocity estimates. Of course, in some other embodiments, the overall solution can be a more complicated function of the individual velocity estimates (e.g., weighted average, etc.).
FIRST COMPARATIVE EXAMPLE
[0047] Prior-art method 200 for a velocity-measuring correlation SONAR is applied to receiver array 104 . Operations 202 through 214 are performed to determine that the receiver pair ( 1 , 14 ) has the best correlation. Velocity vector 420 for best-correlated primary receiver pair ( 1 , 14 ) is depicted in FIG. 4 . A velocity estimate is developed based on pair ( 1 , 14 ), as per operations 216 and 218 .
EXAMPLE APPLYING THE ILLUSTRATIVE METHOD TO THE FIRST COMPARATIVE EXAMPLE
[0048] In this Example, the inventive method is applied to the scenario of Comparative Example 1. Instead of developing only a single velocity solution based on the best-correlated primary receiver pair ( 1 , 14 ) and other primary receiver pairs, a second solution is developed based on a set of redundant receiver pairs that includes a redundant pair that has the same velocity vector as the best-correlated primary receiver pair as well as additional redundant receiver pairs that have the same velocity vector as other primary receiver pairs. Receiver pair ( 5 , 8 ) is a redundant receiver pair that has the same velocity vector as the best-correlated primary receiver pair. FIG. 5 depicts velocity vector 420 for best-correlated primary receiver pair ( 1 , 14 ) and velocity vector 520 for corresponding redundant receiver pair ( 5 , 8 ). Other redundant receiver pairs that correspond to the best-correlated primary receiver pair ( 1 , 14 ) and that could serve as the basis for additional velocity estimates include redundant pairs ( 16 , 13 ) and ( 6 , 9 ).
[0049] The previous Example depicts the application of method 300 to prime (i.e., normally used) hydrophones in array 104 . In other words, in the redundant receiver pair ( 5 , 8 ), both hydrophones are prime. Some receiver arrays include back-up, inactive hydrophones. For example, in array 104 , hydrophones 10 - 12 are back-up hydrophones. They are only used for velocity estimation if a failure is detected in an active hydrophone. In accordance with method 300 , the back-up hydrophones are used, as desired, to create redundant receiver pairs. In this regard, consider the following two Examples.
SECOND COMPARATIVE EXAMPLE
[0050] Prior-art method 200 for a velocity-measuring correlation SONAR is applied to receiver array 104 . Operations 202 through 214 are performed to determine that the receiver pair ( 13 , 2 ) has the best correlation. Velocity vector 630 for best-correlated primary receiver pair ( 13 , 2 ) is depicted in FIG. 6 . A velocity estimate is developed based on best-correlated primary receiver pair ( 13 , 2 ) and other primary receiver pairs, as per operations 216 and 218 .
EXAMPLE APPLYING THE ILLUSTRATIVE METHOD TO THE SECOND COMPARATIVE EXAMPLE
[0051] In this Example, the inventive method is applied to the same scenario of the Second Comparative Example. A second solution is developed based on redundant receiver pair ( 12 , 3 ), which has the same velocity vector as the best-correlated primary receiver pair. It is notable that hydrophone 12 is normally a back-up receiver in array 104 . FIG. 7 depicts velocity vector 630 for best-correlated primary receiver pair ( 13 , 2 ) and velocity vector 740 for corresponding redundant receiver pair ( 12 , 3 ). Other redundant receiver pairs that have the same velocity vector as best-correlated primary pair ( 13 , 2 ) and that could serve as the basis for additional velocity estimates include redundant pairs ( 11 , 4 ) and ( 10 , 5 ). Both these additional redundant pairs incorporate back-up hydrophones.
[0052] In an alternative embodiment, before developing the overall velocity solution, the various velocity estimates are compared to one another. If any one velocity estimate differs from any other velocity estimate by more than a threshold, it is likely to be indicative of a problem in at least one of the hydrophone channels. In such a situation, a notification, warning, or exclusion of velocity estimates from the final solution can be implemented.
[0053] In the illustrative embodiment, the invention provides an improved Spatial correlation SONAR. The invention is also applicable to provide an improved Temporal correlation SONAR. For both types of correlation SONAR, the improvement pertains to the use of redundant receiver pairs to provide additional, substantially independent velocity estimates to provide an improved overall velocity solution.
[0054] Those skilled in the art will understand that there are differences in the way that velocity is calculated for these two types of correlation SONARS. Simply put, Spatial correlation SONAR holds time constant and measures distance while Temporal correlation SONAR holds distance constant and measures time. See, e.g., U.S. Pat. No. 6,804,167 to Scoca, Huber, and Schwartz (“the '167 Patent”) for details concerning velocity calculation for Temporal correlation SONAR and U.S. Pat. No. 4,244,026 to Dickey (“the '026 Patent”) for details concerning the velocity calculation for Spatial correlation SONAR. Both the '167 Patent and the '026 Patent are incorporated by reference herein.
[0055] The calculations that are performed to determine velocity for Spatial correlation SONAR are the same as for Temporal correlation SONAR, as taught in the '167 Patent, up to and including the calculation of correlation products (see, Col. 3 , “RE ij ” and “IM ij ”). This includes the calculations pertaining to pulse location, determination of the number of samples to process, the generation of the I/Q data, etc.) Note, however, that the correlation products are based on different points of data for these two types of SONAR.
[0056] What differs in the calculation methods for the two types of correlation SONARS is the process by which the best correlation (i.e., the best correlated receiver pair) is determined. For Temporal correlation SONAR, the process provided in the '167 Patent is used; for Spatial correlation SONAR, the matrix-based search process described herein is used. Those skilled in the art will be able to use these processes or other processes to search for the best correlation for the velocity solution.
[0057] So, while there are some differences in the velocity calculation techniques, one skilled in the art will readily be able to perform the basic velocity calculation based on a review of the '167 Patent and the '026 Patent. And with an understanding of how to calculate velocity for either Spatial or Temporal correlation SONARS, those skilled in the art we be able to apply the teachings of the present invention relating to the use of additional redundant receiver pairs for the calculation of velocity.
[0058] It is understood that the various embodiments shown in the Figures are illustrative, and are not necessarily drawn to scale. Reference throughout the specification to “one embodiment” or “an embodiment” or “some embodiments” means that a particular feature, structure, material, or characteristic described in connection with the embodiment(s) is included in at least one embodiment of the present invention, but not necessarily all embodiments. Furthermore, it is to be understood that the above-described embodiments are merely illustrative of the present invention and that many variations of the above-described embodiments can be devised by those skilled in the art without departing from the scope of the invention. It is therefore intended that such variations be included within the scope of the following claims and their equivalents.
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A correlation SONAR that provides improved velocity estimates due to a reduction in random and bias errors is disclosed. Rather than basing the velocity estimate on a single set of primary receiver pairs, one or more additional velocity estimates are generated based on one or more available receiver pair sets having the same velocity vectors as the primary receiver pairs set. Additional velocity estimates also provide a reliability and accuracy improvement by enabling identification and subsequent elimination of erroneous velocity estimates.
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RELATED APPLICATION
[0001] The present invention is based on, and claims priority from, Korean Application No. 2004-29477, filed on Apr. 28, 2004, the disclosure of which is incorporated by reference herein in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a method of growing a nitride single crystal, and, more particularly, to a method of growing a high quality nitride single crystal on a silicon substrate, a nitride semiconductor light emitting device using the same, and a method of manufacturing the nitride semiconductor light emitting device.
[0004] 2. Description of the Related Art
[0005] A nitride semiconductor light emitting device is a high power optic device, which generates light having a short wavelength, such as blue or green light, and thereby enables full color to be realized, and is spotlighted in the field of related technologies. Generally, a nitride semiconductor light emitting device is made of a nitride single crystal having the formula Al x In y Ga (1-x-y) N (where 0≦x≦1, 0≦y≦1, 0≦x+y≦1).
[0006] In order to manufacture such a nitride semiconductor light emitting device, it is necessary to provide a technology for growing a high quality nitride single crystal. However, there is a problem in that substrates currently used for growing the nitride single crystal are not appropriate due to differences in lattice parameters and thermal expansion coefficients between the substrate and the nitride single crystal.
[0007] Generally, the nitride single crystal is grown on a dissimilar substrate, such as a sapphire (Al 2 O 3 ) substrate or a SiC substrate, by means of the MBE (Molecular Beam Epitaxy) process or a vapor phase growth process, such as the MOCVD (Metal Organic Chemical Vapor Deposition) process, the HVPE (Hydride Vapor Phase Epitaxy) process, etc.
[0008] Since the dissimilar substrate, such as a sapphire (α-Al 2 O 3 ) substrate or a SiC substrate, is not only high priced, but also very restricted to a size of 2 or 3 inches, it is not appropriate for mass production.
[0009] Accordingly, it is needed to use a Si substrate, which is most generally used as a substrate in the semiconductor industry, including the light emitting device industry. However, due to differences in lattice parameter and thermal expansion coefficient between the Si substrate and a GaN single crystal, there is a problem in that cracks can be created at an interface between the sapphire substrate and the GaN single crystal to such an extent that the GaN layer cannot be practically used. As for a method of relieving the differences, provision of a buffer layer on the Si substrate has been suggested, but this method is not regarded as an appropriate method for solving the problem as mentioned above. FIGS. 1 a and 1 b show a GaN single crystal grown by use of a conventional AlN buffer layer and a buffer structure, which is combined with the AlN buffer layer and an AlGaN intermediate layer.
[0010] First, as shown in FIG. 1 a , a conventional AlN buffer layer 12 is formed on a (111) plane of a Si substrate 11 , and a GaN single crystal 15 having a thickness of 2 μm is grown on the AlN buffer layer 12 . FIG. 2 a is an optical micrograph showing a surface of the GaN single crystal 15 of FIG. 1 a . As shown in FIG. 2 a , it can be seen that a plurality of cracks are created on the surface of the GaN single crystal 15 . These cracks are created due to unresolved differences in lattice parameter and thermal expansion coefficient between the Si substrate and the GaN single crystal, thereby not only deteriorating performance of the device and life span thereof, but also making it impossible to use the GaN single crystal in practice.
[0011] As an alternative method, as shown in FIG. 1 b , with an AlN buffer layer 12 formed on a (111) plane of a Si substrate 11 , a Al x Ga 1-x N intermediate layer 13 having Al compositions (x) of 0.87 to 0.07 and a total thickness of 300 nm is formed on the AlN buffer layer 12 , and a GaN single crystal 15 having a thickness of 2 μm is grown thereon. FIG. 2 b is an optical micrograph showing a surface of the GaN single crystal 15 of FIG. 1 b . As shown in FIG. 2 b , it can be seen that, although the number of cracks created on the surface of the GaN single crystal 15 of FIG. 1 b is decreased in comparison to the GaN single crystal 15 of FIG. 2 a , a number of cracks are still created on the surface of the crystal 15 of FIG. 1 b . That is, it can be understood that the buffer structure suggested in FIG. 1 b cannot satisfy requirements for growing the high quality single crystal.
[0012] Accordingly, in the field of the prior art, there is a need to provide a method of growing a high quality nitride single crystal layer, which does not create cracks, on an Si substrate, and a nitride semiconductor light emitting device using the same.
SUMMARY OF THE INVENTION
[0013] The present invention has been made to solve the above problems, and it is an object of the present invention to provide a method of growing a nitride single crystal layer, using a buffer layer comprising Si and Ge in order to allow a high quality nitride single crystal layer to be grown on a silicon substrate.
[0014] It is another object of the present invention to provide a nitride semiconductor light emitting device comprising a nitride single crystal layer grown on a silicon substrate, and a method of manufacturing the same.
[0015] In accordance with one aspect of the present invention, the above and other objects can be accomplished by the provision of a method of growing a nitride single crystal layer, comprising the steps of: preparing a silicon substrate having an upper surface of a (111) crystal plane; forming a buffer layer having the formula of Si x Ge 1-x , (where 0<x≦1) on the upper surface of the silicon substrate; and forming a nitride single crystal on the buffer layer.
[0016] The method may further comprise forming an intermediate layer having the formula of Al y In z Ga (1-y-z) N, (where 0≦y≦1, 0≦z≦1, 0≦y+z≦1) on the buffer layer before forming the nitride single crystal.
[0017] The buffer layer may have an Si composition (x) of about 0.1˜0.2, and more preferably of about 0.14.
[0018] In order to efficiently reduce differences in lattice parameter and thermal expansion coefficient between the silicon substrate and the nitride single crystal, preferably, the buffer layer has an Si composition gradient (x) gradually decreasing from a portion, where the buffer layer contacts the silicon substrate, to an uppermost portion of the buffer layer. More preferably, the buffer layer has an Si composition gradient (x) gradually decreasing from 1 to 0.1 from the portion, where the buffer layer contacts the silicon substrate, to the uppermost portion of the buffer layer, respectively. Most preferably, the buffer layer has an Si composition gradient (x) gradually decreasing from 1 to 0.14 from the portion, where the buffer layer contacts the silicon substrate, to the uppermost portion of the buffer layer, respectively.
[0019] The buffer layer may have a thickness of at least 20 nm in order to sufficiently secure a buffering function.
[0020] In accordance with another aspect of the present invention, there is provided a nitride semiconductor light emitting device using the method of growing a nitride single crystal layer, the nitride semiconductor light emitting device comprising: a silicon substrate having an upper surface of a (111) crystal plane; a buffer layer having the formula of Si x Ge 1-x , (where 0<x≦1) on the silicon substrate; a first conductive nitride semiconductor layer on the buffer layer; an active layer on the first conductive nitride semiconductor layer; and a second conductive nitride semiconductor layer on the first conductive nitride semiconductor layer.
[0021] In accordance with yet another aspect of the present invention, there is provided a method of manufacturing a nitride semiconductor light emitting device by use of the method of growing a nitride single crystal layer, the method comprising the steps of: preparing a silicon substrate having an upper surface of a (111) crystal plane; forming a buffer layer having the formula of Si x Ge 1-x , (where 0<x≦1) on the silicon substrate; forming a first conductive nitride semiconductor layer on the buffer layer; forming an active layer on the first conductive nitride semiconductor layer; and forming a second conductive nitride semiconductor layer on the first conductive nitride semiconductor layer.
[0022] According to the present invention, the buffer layer employed for growing the nitride single crystal on the silicon substrate comprises a Si x Ge 1-x , layer, (where 0<x≦1). Since Si and Ge are perfectly soluble in the Si x Ge 1-x layer, there is an advantage in that the compositions of Si or Ge can be continuously varied from 0 to 1.
[0023] Additionally, in case of the conventional AlN buffer layer, there are differences of 24.8% and 40.7% in thermal expansion coefficient between the GaN layer and the AlN layer and between the AlN layer and the Si substrate, respectively, causing a severe problem of cracks due to the differences in thermal expansion coefficient. However, according to the present invention, since the Si 0.14 Ge 0.86 buffer layer has a thermal expansion coefficient approximately the same as that of the GaN layer, the problems caused by the differences in thermal expansion coefficient can be effectively solved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The foregoing and other objects and features of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
[0025] FIGS. 1 a and 1 b show structures of a nitride single crystal grown on a silicon substrate according to a conventional method;
[0026] FIGS. 2 a and 2 b are optical micrographs showing surfaces of the nitride single crystals shown in FIGS. 1 a and 1 b;
[0027] FIGS. 3 a and 3 b show structures of a nitride single crystal grown on a silicon substrate according to different embodiments of the present invention, respectively; and
[0028] FIG. 4 is a section side elevation illustrating a nitride semiconductor light emitting device according to one embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] Preferred embodiments will now be described in detail with reference to the accompanying drawings.
[0030] FIGS. 3 a and 3 b show structures of a GaN single crystal grown by use of a SiGe buffer layer in accordance with the present invention.
[0031] According to the embodiment of the present invention shown in FIG. 3 a , a Si x Ge 1-x layer (where 0<x≦1) is provided as a buffer layer 34 on a silicon substrate 31 . At this time, the silicon layer 31 has an upper surface of a (111) crystal plane. A GaN single crystal 35 is grown on the Si x Ge 1-x layer 34 by use of a well-known process of growing a nitride single crystal, such as the MOCVD process. According to the present invention, the Si x Ge 1-x layer 34 preferably has an Si composition (x) of about 0.1˜0.2, and more preferably of about 0.14. When the Si x Ge 1-x layer 34 comprises an Si composition (x) of about 0.14, since a difference in thermal expansion coefficient between the GaN layer and the Si x Ge 1-x layer 34 is approximately 0, stress caused by the difference in thermal expansion coefficient therebetween can be remarkably reduced.
[0032] The Si x Ge 1-x layer 34 may be provided as a structure of a SiGe single layer or of Si/SiGe layers. Preferably, since Si and Ge are perfectly soluble with each other in the Si x Ge 1-x layer 34 , and the Si composition therein can be controlled to be gradually decreased, the Si x Ge 1-x layer 34 may have an Si composition gradient (x) gradually decreasing from a portion, where the Si x Ge 1-x layer 34 contacts the silicon substrate 31 , to an uppermost portion of the Si x Ge 1-x layer 34 (that is, to a portion where a GaN single crystal 35 will be formed). The Si composition preferably increase in the range of 1 to 0.1, and more preferably in the range of 1 to 0.14, from the portion where the Si x Ge 1-x layer 34 contacts the silicon substrate 31 to the uppermost portion of the Si x Ge 1-x layer 34 .
[0033] Additionally, unlike the conventional AlN buffer layer, the Si x Ge 1-x layer 34 may be grown to a thickness, which can sufficiently secure buffering effects between dissimilar materials. For instance, in the case of the conventional AlN buffer layer, it is difficult to grow it to a thickness of 1 μm or more, and thus, there is a problem in that a sufficient buffering region cannot be secured. However, since the Si x Ge 1-x layer 34 can be grown to a thickness of several dozen nm, it is desirable that the Si x Ge 1-x layer 34 be grown to a thickness of at least 20 nm in order to secure a sufficient buffering region.
[0034] Alternatively, the present invention may be realized as the embodiment shown in FIG. 3 b . As with FIG. 3 a , according to the embodiment shown in FIG. 3 b , after a Si x Ge 1-x , layer 34 (where 0<x≦1) is formed on a silicon substrate 31 , which has an upper surface of a (111) crystal plane, an intermediate layer 33 having the formula of Al y In z Ga (1-y-z) N (where 0≦y≦1, 0≦z≦1, 0≦y+z≦1) may be formed on the Si x Ge 1-x layer 34 . The Al y In z Ga (1-y-z) N intermediate layer 33 acts as a buffer layer, as with the AlGaN layer 13 illustrated in FIG. 1 b . According to the embodiment of the present invention, with the stress due to differences in heat expansion coefficient between the layers removed by means of the Si x Ge 1-x layer 34 , growth of a nitride single layer 35 can be imparted with enhanced quality by use of the Al y In z Ga (1-y-z) N intermediate layer 33 .
[0035] FIG. 4 is a section side elevation illustrating a nitride semiconductor light emitting device according to another embodiment of the present invention.
[0036] Referring to FIG. 4 , a nitride semiconductor light emitting device 40 according to the present invention comprises a buffer layer 44 having the formula of Si x Ge 1-x (where 0<x≦1) formed on a silicon substrate 41 . The nitride semiconductor light emitting device 40 further comprises a first conductive nitride semiconductor layer 45 , an active layer 46 , and a second conductive nitride semiconductor layer 47 sequentially formed on the buffer layer 44 . Additionally, the nitride semiconductor light emitting device 40 comprises an n-side electrode 49 a on an upper surface of the first conductive nitride semiconductor layer 45 , where some portion of the second conductive nitride semiconductor layer 47 and active layer 46 is removed, a transparent electrode 48 on the second conductive nitride semiconductor layer 47 for enhancing contact resistance, and a p-side electrode 49 b on the transparent electrode 48 .
[0037] The first conductive nitride semiconductor layer 45 may comprise a first conductive GaN layer formed on the Si x Ge 1-x buffer layer 44 , and a first conductive AlGaN layer on the first conductive GaN layer. The second conductive nitride semiconductor layer 47 may comprise a second conductive GaN layer formed on the active layer 46 , and a second conductive AlGaN layer on the second conductive GaN layer. The active layer 46 may be a GaN/InGaN active layer having a multi-well structure.
[0038] The Si x Ge 1-x layer 44 of the present invention preferably has an Si composition (x) of about 0.1˜0.2, and more preferably of about 0.14. When the Si x Ge 1-x layer 34 has an Si composition (x) of about 0.14, since a difference in thermal expansion coefficient between the GaN layer and the Si x Ge 1-x layer 34 is approximately 0, stress caused by the differences in thermal expansion coefficient therebetween can be remarkably reduced.
[0039] Meanwhile, it should be noted that the present invention is not limited to the above embodiment. For instance, effects of the differences in thermal expansion coefficient between the layers is not restricted to a typical tension, even though the Si composition is reduced below 0.14, the present invention may be designed to intentionally generate a compression stress in order to complement a tension generated in a region between other layers.
[0040] Preferably, since Si and Ge are perfectly soluble in the Si x Ge 1-x layer 44 , and the Si composition therein can be controlled to be gradually decreased, the Si x Ge 1-x layer 44 may have the Si composition gradient (x) gradually decreasing from a portion where the Si x Ge 1-x layer 44 contacts the silicon substrate 41 to a portion where the Si x Ge 1-x layer 44 contacts the first conductive nitride semiconductor layer 45 . The Si composition preferably increase in the range of 1 to 0.1, and more preferably in the range of 1 to 0.14, from the portion where the Si x Ge 1-x layer 44 contacts the silicon substrate 41 to the uppermost portion of the Si x Ge 1-x layer 44 . Since the Si x Ge 1-x layer 34 can be grown to a thickness of several dozen nm, it is desirable that the Si x Ge 1-x layer 44 be grown to a thickness of at least 20 nm in order to secure a sufficient buffering region.
[0041] Furthermore, in the process of manufacturing the nitride semiconductor light emitting device, since the Si x Ge 1-x buffer layer can be easily etched, it is advantageous in that the Si substrate can be lifted off, if necessary.
[0042] Meanwhile, although the structure shown in FIG. 4 has only the SiGe buffer layer, as with the embodiment shown in FIG. 3 b , after the Si x Ge 1-x layer 44 (where 0<x≦1) is formed on the silicon substrate 41 , which has an upper surface of a (111) crystal plane, an intermediate layer having the formula of Al y In z Ga (1-y-z) N (where 0≦y≦1, 0≦z≦1, 0≦y+z≦1) may be formed on the Si x Ge 1-x layer 44 .
[0043] As apparent from the above description, according to the present invention, the method of growing a high quality nitride single crystal by use of the buffer layer comprising Si and Ge on the silicon substrate. The buffer layer of the present invention has a thermal expansion coefficient approximately similar to that of the GaN single crystal, sufficiently secures a growth thickness, and makes it possible to generate an intentional compression stress for compensating for a tension generated from other regions, enabling a high quality nitride single crystal to be grown on the silicon substrate.
[0044] Accordingly, in manufacturing the nitride semiconductor light emitting device, the silicon substrate may be used as a substrate for growth of the nitride single crystal, instead of a sapphire substrate or a SiC substrate having a high price.
[0045] It should be understood that the embodiments and the accompanying drawings as described above have been described for illustrative purposes and the present invention is limited by the following claims. Further, those skilled in the art will appreciate that various modifications, additions and substitutions are allowed without departing from the scope and spirit of the invention as set forth in the accompanying claims.
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A method of growing a nitride single crystal layer, and a method of manufacturing a light emitting device using the method are disclosed. The method of growing a nitride single crystal layer comprises the steps of preparing a silicon substrate having an upper surface of a crystal plane ( 111 ), forming a buffer layer having the formula of Si x Ge 1-x , (where 0<x≦1) on the upper surface of the silicon substrate, and forming a nitride single crystal on the buffer layer. Also, a nitride light emitting device using the method manufactured by the method, and a method of manufacturing the same are disclosed.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Non-provisional Application of U.S. Provisional Application No. 61/353,487, titled: SUPEROLEOPHOBIC AND SUPERHYDROPHILIC FABRIC FILTERS FOR RAPID WATER-OIL SEPARATION, filed on Jun. 10, 2010, herein incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention is related generally to the field of contamination separation, and in particular the separation of oil from sea water.
BACKGROUND OF THE INVENTION
[0003] A technique for separating oil from water via a cotton, polyester, or leather filter coated with a chemical that blocks the contaminant, such as oil, while allowing water to pass through does not exist that removes 95% or more of the contaminant from the water.
SUMMARY OF THE INVENTION
[0004] According to the invention, there is provided a Superoleophobic and Superhydrophilic Fabric Filter, as defined in claims 1 - 13 .
[0005] The present invention is an article and a technique for separating oil from water via, for example, a cotton, polyester, or leather filter coated with a chemical that blocks oil while allowing water to pass through.
[0006] For a better understanding of the present invention, together with other and further embodiments thereof, reference is made to the accompanying drawings and detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The present invention is illustratively shown and described in reference to the accompanying drawings, in which:
[0008] FIGS. 1 a - 1 b are pictorial images of the present invention demonstrating separation of sea water from crude oil using a treated cotton filter, and illustrating on the surface of treated cotton, water (stained with a blue dye to aid the observation) easily spreads, while oil forms a bead.
DETAILED DESCRIPTION OF THE INVENTION
[0009] As used herein in the specification and claims, including as used in the examples and unless otherwise expressly specified, all numbers may be read as if prefaced by the word “about”, even if the term does not expressly appear. Also, any numerical range recited herein is intended to include all sub-ranges subsumed therein.
[0010] Now turning to FIG. 1 a that illustrates one embodiment of the present invention filtering oil from contaminated water samples. The filter includes a chemical that is both hydrophilic and oleophobic. On the surface of ordinary cotton treated with the chemical, water easily spreads, while oil forms beads, as shown in FIG. 1 b . When used as a filter, such treated fabric of cotton, polyester, or leather allows water to pass through it but does not allow oil to pass through it. The filter can be produced by submerging the cotton in an aqueous solution containing the chemical then drying it in an oven or in open air. The size of the fabric can be tailored to the size of the devices that remove contamination in a body of water. For example, the massive slick off the Gulf Coast may require large, trough-shaped filters that could be dragged through the water to capture surface oil. The oil could be recovered and stored and the filter reused.
[0011] The cost for treating the fabric with the chemical of the present invention is very low, estimated to be less than $0.1 per square foot of fabric. Only very small amount of chemical is needed to treat the cotton or equivalent fabric. It is estimated that 1 pound of the chemical is enough to treat more than 2,000 square foot cotton or fabric.
[0012] The chemical binds strongly to the cotton. Experiments have demonstrated that the treated fabric being submerged in water-oil mixture for more than a month without noticing significant change in either the oil-repellency of the cotton or the separation efficiency of the filter.
[0013] One embodiment of the chemical composition comprises at least one oleophobic section (typically fluorocarbon groups) and one hydrophilic section (typically groups that possess positive or negative charges in an aqueous solution). Such chemicals may be selected from a large pool of candidates. The chemicals can be either synthesized or commercially available. The three methods that are described below are examples for preparing such chemicals and not meant to limit the invention
[0014] Methods for Producing the Fluorinated Chemical
[0015] Method 1 (Products are Mono Phosphate Ester and Small Amount of Bis Phosphate Ester)
[0016] The fluoroalkyl phosphates were synthesized according to Scheme 1 (below). Briefly, 3,3,3-trifluoro-1-propanol is added to equal molar phosphoryl chloride with vigorous stirring at such a rate that the temperature is kept between about 20° C. and about 30° C., but most preferrably about 25° C. The resulting mixture is warmed to about 45° C. to 55° C., but most preferrably about 50° C. for about 4 hours 30 minutes to 5 hours 30 min, but most preferrably about 5 hr, and the evolving hydrogen chloride is removed from the reaction mixture by reducing the pressure to 0.5-1 atm. After cooling to room temperature, the final mixture is poured into a water/ice mixture and stirring is continued for about 4 hours 30 minutes to 5 hours 30 min, but most preferrably about 5 hours. Then, ether is added, and the organic layer is separated by density difference. Evaporation of the ether yields the product containing fluoroalkyl phosphates. Diethanolamine (DEA) salts of the fluoroalkyl phosphates are prepared by neutralizing the phosphates with appropriate amounts of diethanolamine by stoichiometry.
[0000]
[0017] Method 2 (the Products are Mixture of Mono Phosphate Ester and Bis Phosphate Ester)
[0018] In one embodiment of the present invention, 142 g±14 g (1.0 mole±0.1 mole) of phosphorus pentoxide is gradually added to 342.21 g+34 g (3±0.3 moles) of 3,3,3-trifluoro-1-propanol in a 1000 ml three-necked flask with stirring at such a rate that the temperature is kept, by cooling, about 50° C.±5° C. The mixture is left to react for about 3 hours 30 minutes to 4 hours 30 minutes at about 75° C. to about 85° C., but most preferrably about 80° C. After addition of 54 g±5 g DI water, the mixture is stirred for another about 2 hours 30 minutes to 3 hours 30 min, but most preferrably 3 hours at about 75° C. to about 85° C., but most preferrably about 80° C. Thereafter, appropriate amounts of diethanolamine were added for neutralization by stoichiometry. The product is obtained by extraction with ethyl ether and distillation.
[0000]
[0019] Method 3
[0020] In one embodiment of the present invention, 100 g±10 g (0.67 mole±0.07 mole) methydichorophosphate (MePOCl 2 ) is added drop-wise to a mixture of 300 mL±30 mL anhydrous ether, 131.93 g±13 g (1.67 mole±0.17 mole) pyridine, and 1.67 mole±0.17 mole 3,3,3-trifluoro-1-propanol under stirring at approximately about 3° C. to 7° C., but most preferrably 5° C. The mixture is refluxed for about 1 hour 30 minutes to 2 hours 30 min, but most preferrably about 2 hours. The reaction mixture is cooled in a refrigerator and pyridinium salt is then filtered. The filtrate is washed first by 10 w.t. % sulfuric acid solution in NaCl saturated distilled water and then by NaCl saturated distilled water alone. The resultant organic phase is dried over MgSO 4 and then fractionated 3 times. Final distillates of the products are collected.
[0021] The technology for treating a fabric with Superoleophobic and Superhydrophilic chemicals to form fabric filters may also find use in many other applications where water needs to be separated from oil, including separating gross amounts of oil from the wastewater effluents of oil refineries, petrochemical plants, chemical plants, natural gas processing plants and other industrial sources, and separating oil from the bilge water accumulated in ships as required by the international MARPOL Convention.
[0022] While the disclosure has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope of the embodiments. Thus, it is intended that the present disclosure cover the modifications and variations of this disclosure provided they come within the scope of the appended claims and their equivalents.
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Product, method of making product, and technique for using product to separate oil from water via a filter, such as cotton, polyester, or leather, coated with a chemical that blocks oil while allowing water to pass therethrough.
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FIELD OF THE INVENTION
The invention relates to cells for the production of aluminium by the electrolysis of a molten electrolyte, in particular the electrolysis of alumina dissolved in a molten halide electrolyte such as cryolite, comprising anodes immersed in the molten electrolyte above a cell bottom whereon molten product aluminium is collected in a pool which contains bodies of aluminium-resistant material.
BACKGROUND OF THE INVENTION
Aluminium is produced conventionally by the Hall-Heroult process, by the electrolysis of alumina dissolved in cryolite-based molten electrolytes at temperatures up to around 950° C. A Hall-Heroult reduction cell typically has a steel shell provided with an insulating lining of refractory material, which in turn has a lining of carbon which contacts the molten constituents. Conductor bars connected to the negative pole of a direct current source are embedded in the carbon cathode forming the cell bottom floor. The cathode is usually an anthracite or graphite based carbon lining made of prebaked cathode blocks, joined with a ramming mixture or glue.
In Hall-Heroult cells, a molten aluminium pool acts as the cathode surface. The carbon bottom lining or cathode material has a useful life of three to eight years, or even less under adverse conditions. The deterioration of the cathode bottom is due to erosion and penetration of electrolyte and liquid aluminium as well as penetration of sodium into the carbon, which by chemical reaction and intercalation causes swelling, deformation and disintegration of the cathode carbon blocks and ramming mix. In addition, the penetration of sodium species and other ingredients of cryolite or air leads to the formation of toxic compounds including cyanides.
Difficulties in operation also arise from the accumulation of undissolved alumina sludge on the surface of the carbon cathode beneath the aluminium pool which forms insulating regions on the cell bottom. Penetration of cryolite and aluminium through the carbon body and the deformation of the cathode carbon blocks also cause displacement of such cathode blocks. Due to displacement of the cathode blocks and the formation of cracks, aluminium reaches the steel cathode conductor bars causing corrosion thereof leading to deterioration of the electrical contact, non uniformity in current distribution and an excessive iron content in the aluminium metal produced.
Extensive research has been carried out with Refractory Hard Metals (RHM) such as TiB 2 as cathode materials. TiB 2 and other RHM's are practically insoluble in aluminium, have a low electrical resistance, and are wetted by aluminium. This should allow aluminium to be electrolytically deposited directly on an RHM cathode surface, and should avoid the necessity for a deep aluminium pool.
Because titanium diboride and similar Refractory Hard Metals are wettable by aluminium, resistant to the corrosive environment of an aluminium production cell, and are good electrical conductors, numerous cell designs utilizing Refractory Hard Metal have been proposed, which would present many advantages, notably including the saving of energy by reducing the anode-cathode distance (ACD).
U.S. Pat. No. 3,856,650 proposed lining a carbon cell bottom with a ceramic coating upon which parallel rows of tiles are placed, in the molten aluminium, and spaced apart from one another by expansion gaps in a grating-like arrangement. The purpose of this "grating" was to protect the ceramic coating against mechanical effects due, for example, to movements of the aluminium pool.
U.S. Pat. No. 4,243,502 described designs for aluminium-wettable cathodes some of which had a generally horizontal active surface supported by one or more supporting plates, usually connected to a current supply by an extension protruding from the top of the electrolyte, between the anodes. Such designs were not practicable.
U.S. Pat. No. 4,410,412 described wettable cathodes made of aluminide materials. These cathodes were supposed to be exchangeable, by holding several cathode elements together in a holder of insoluble refractory material. Special cell designs to make use of such aluminides were also described in U.S. Pat. No. 4,462,886. Again, such materials and designs did not prove to be practicable.
PCT patent application W083/04271 proposed cathodic elements of refractory hard materials such as titanium diboride in the shape of mushrooms having relatively large flat tops facing the anode in order to maximize the active cathode surface. However, no adequate means could be found for connecting the mushroom stems to the cell bottoms, so this design also failed.
To accommodate for fluctuations in the level of the pool of aluminium, European patent EP-B-0'082'096 proposed the use of floating cathode elements made of titanium diboride combined with a lighter material to reduce its density, for instance graphite. These floating elements were restrained by elements connected to the cell bottom, leading to an impractical design.
EP-A-0'103'350 proposed the use of tubular cathode elements, for example of titanium diboride, which rest on the cell bottom dipping in a shallow aluminium pool. The inner diameter of the elements was such as to maintain molten aluminium up to near the tops of the tubes by capillary action. These individual tubes were distributed over the cell bottom with a suitable spacing, and were to remain on the cell bottom during use.
To restrict movement in a "deep" cathodic pool of molten aluminium, U.S. Pat. No. 4'824'531 proposed filling the cell bottom with a packed bed of loose pieces of refractory material. Such a design has many potential advantages but, because of the risk of forming a sludge by detachment of particles from the packed bed, the design has not found acceptance.
Despite extensive efforts and the potential advantages of having surfaces of titanium diboride at the cell cathode bottom, such propositions have not been commercially adopted by the aluminium industry.
Recently, a number of proposals have been made for the feasible, low-cost production of various composite materials containing or coated with titanium diboride or other refractory ceramic materials, enabling promising applications in many of the already-proposed cell designs.
For instance, WO/93/20027 discloses forming protective refractory coatings on a conductive substrate like carbon starting from a micropyretic reaction layer from a slurry containing reactants in a colloidal carrier. WO/93/20026 discloses protective coatings applied from a colloidal slurry containing particulate reactant or non-reactant substances. WO/93/25731 more particularly describes the application of pre-formed refractory borides in a colloidal carrier to carbon cell components of aluminium production cells.
Such coating materials have in particular enabled substantial improvements in the conventional cell bottom designs. However, it has turned out that many of the heretofore proposed "new" cell designs are unsatisfactory in one or more respects, even with materials that stand up in the environment.
OBJECTS OF THE INVENTION
One object of the invention is to provide a cell in which the anode-cathode distance ACD can be made small due to there being only small ripples or no ripples on the surface of the aluminium pool, or due to there being a drained cathode configuration.
Another object of the invention is to provide means which reduce or eliminate horizontal movement of the aluminium pool which would erode the cathode and reduce current efficiency, redissolving the metal in the bath.
A further object of the invention is to provide, in the aluminium pool, bodies of a material of low resistivity which make good contact with the cathode cell bottom, permitting a low voltage drop between the cathode cell bottom and the active cathode surface even with sludge formation.
Another object of the invention is to provide means which permit operation of the cell with a shallow aluminium pool and which provide a better and more uniform current distribution.
Yet another object of the invention is to provide bodies for stabilizing the aluminium pool, which bodies are mechanically strong, easy to place on the cell bottom, remain firmly in place during operation, can withstand the cell conditions for long periods of time without disintegrating and unwantedly depositing sludge on the cell bottom, and remain mechanically strong even after long periods of service and can be lifted from the cell for servicing or replacement.
A further object of the invention is to provide a cell whose operation costs can be reduced considerably, whose aluminium inventory can be much smaller than in conventional cells if desired and wherein, even when the cell is operated with a deep pool of molten aluminium, magnetohydrodynamic effects are reduced.
SUMMARY OF THE INVENTION
In its main aspect, the invention provides a cell for the production of aluminium by the electrolysis of a molten electrolyte, in particular the electrolysis of alumina dissolved in a molten halide electrolyte such as cryolite, comprising a plurality of anodes immersed in the molten electrolyte above a cell bottom whereon molten product aluminium is collected in a pool containing bodies made of or coated with aluminium-resistant material.
According to the invention, the anodes are associated with an assembly (called a grid or grid-like assembly) of side-by-side upright or inclined walls of aluminium-resistant material having top ends placed under the anode and bottom ends standing on the cell bottom covered by the pool of molten aluminium. The bottom ends of the walls form a base which is large compared to the height of the walls so that the grid-like assembly when resting on its base is stable, each such grid-like assembly standing on the cell bottom and being removable from the cell.
In some embodiments at least part of the walls of the grid-like assembly are made of electrically conductive material. In other embodiments where the grid-like assembly remains immersed, at least part of the walls of the grid-like assembly are made of material of high electrical resistivity. All or part of the walls of the grid-like structures may be made of or coated with an aluminium wettable material in particular a refractory boride such as titanium diboride and/or may be made of or coated or impregnated with a cryolite resistant material. When the walls protrude outside the molten aluminium to form an active cathode surface they must be made of electrically conductive material which is cryolite resistant and aluminium-wettable or is suitably coated to provide these properties.
The walls of each grid-like assembly may have aluminium-wettable top parts which protrude above the molten product aluminium, thereby forming drained cathode surfaces facing the associated anode.
In some drained-cathode embodiments, the protruding top parts of the grid walls forming drained cathode surfaces are inclined, facing corresponding inclined surfaces of the anodes, thereby facilitating gas release and promoting uniform wear of the anodes when they are formed of pre-baked carbon bodies, it however being understood that the dimensionally stable non-carbon anodes will usually be preferred.
Alternatively, the grids may remain totally immersed in the pool of molten aluminium with a stabilized surface layer of molten aluminium over the tops of the grid walls.
The cell bottom is advantageously made of carbon or a carbon-based material, having a surface layer of electrically-conductive RHM-containing material on which the grids stand. Such a layer is of paramount importance because it protects the underlying carbon cathode from sodium penetration and avoids deformations of the cell bottom which would make the grid unstable. Advantageously, such coating material is of the type disclosed in WO/93/25731.
The walls of the grids are usually vertical to the plane of the grid base, but some or all of the walls can be inclined by an angle up to 30° to the vertical from the plane of the grid base, for instance inclined up to 15° to vertical so the top of the assembly is smaller than the base.
In one advantageous embodiment, the grids are formed by a series of plates intersecting one another, preferably at right angles, the intersecting plates defining a series of generally vertical openings through the assembly, the intersecting plates usually having end parts protruding from the outer faces of the two outermost plates with which they intersect. Such intersecting plates provide a mechanically strong grid, which can be assembled to any desired shape and size, and whose height is usually much less than the width and length, so when the grid is placed on the cell bottom it will remain stable.
Other grid-like assemblies may be formed by tubular pieces joined together side-by-side, in which case the tubular pieces define a series of generally vertical openings through the assembly, these openings being provided inside the tubular pieces and possibly also between the tubular pieces. These tubular pieces may have any desired cross-sectional shape such as round, square, rectangular, hexagonal etc.
The grids or other assemblies could also be formed by profiled sections assembled side-by-side to define a series of generally vertical openings through the assembly.
It is also possible to make a grid from a series of plates held in spaced-apart parallel configuration by transverse securing members such as cross-bars.
The bottom ends of the walls may be spaced above the cell bottom or have apertures allowing passage of molten aluminium on the cell bottom within the lower end part of the grid-like assembly between the bottom parts of the walls forming the grid-like assembly. In one embodiment the top parts of at least some of the walls of the grid-like assembly have recesses serving as guides which receive the lower ends of anode plates suspended above the grid-like assembly. In this arrangement, advantageously other walls of the grid-like assembly intersect with said recessed walls, and are made of electrically-conductive material, these other walls protruding above the molten product aluminium. The parts of the walls which protrude above the molten product alumina are made of or coated with aluminium-wettable material.
The assemblies according to the invention, particularly grids made of intersecting walls, are mechanically strong, easy to place on the cell bottom, and remain firmly in place during operation. They can withstand the cell conditions for long periods of time without disintegrating, and remain mechanically strong even after long periods of service and can be lifted from the cell for servicing or replacement.
The invention also encompasses use of such cells for the production of aluminium by the electrolysis of alumina dissolved in a molten halide electrolyte such as a cryolite, where the grids serve to restrain movements in the pool of molten aluminium, and wherein during operation the grids (or other assemblies) are removed periodically or when necessary for servicing or replacement, and new or serviced grids are replaced in the cell.
Operation of the cell is advantageously in a low temperature process, with the molten halide electrolyte containing dissolved alumina at a temperature below 900° C., usually at a temperature from 680° C. to 880° C. The low temperature electrolyte may be a fluoride melt or a mixed fluoride-chloride melt. This low temperature process is operated at low current densities on account of the low alumina solubility.
However, the invention is particularly advantageous also in conventional cell designs where the carbon blocks are assembled to form the cell bottom, preferably with the inclusion of a refractory coating on the conventional cathode surface to support the grids. Existing cells can thus be retrofitted by inserting these grids on a coated carbon bottom.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention will be further described by way of example, with reference to the accompanying schematic drawings, in which:
FIG. 1 is a perspective view of one example of a grid according to the invention;
FIGS. 2a and 2b are side views of plates which can be assembled together, or with other similar plates, or with plates of different shapes to form a grid according to the invention;
FIG. 3 is a partial view of an electrolytic aluminium production cell with an anode above a grid according to the invention;
FIG. 4 is another partial view of an electrolytic aluminium production cell with an anode having a downwardly-facing sloping surface cooperating with inclined top parts of a cathode-forming grid according to the invention;
FIG. 5 is a top view of a grid-like assembly according to the invention with polygonal openings; and
FIGS. 6 is a side view of a different grid-like assembly according to the invention showing how it cooperates with anodes.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 shows a grid 10 made by assembling together a series of plates 11 and 12 at right angles to form a rectangular body having rows of side-by-side openings 13 opening into the top and bottom surfaces. In their bottom edges, some of the plates have apertures 14 of suitable size and shape to allow molten aluminium to penetrate inside the grid and fill the bottom part of the openings 13 when the grid 10 is placed on the cell bottom of an aluminium production cell. As shown, the plates 11 and 12 have protruding end parts 16 and 17 respectively which extend beyond the outermost plates with which they intersect.
The height of grid 10 is small compared to the size of its base formed by the bottom ends of plates 11 and 12, so that the grid is stable when placed on its base. As illustrated, the height is about 1/3 the width and length of the grid and usually it will be much less, for instance 1/10th or less. At the other extreme, the height will not be less than the shortest side dimension, usually no more than one half the shortest side dimension. These dimensions will of course be chosen as a function of the cell configuration in which the grids are to be used.
By way of example, FIG. 1 shows six plates 11 intersecting at 90° with six plates 12. Any suitable number of plates may be chosen. The openings 13 may be of square or rectangular cross-section, or lozenge-shaped. Usually the lengths of plates 11 and 12 will be selected so that the grid 10 corresponds at least approximately in size to an anode of the aluminium production cell below which the grid will be placed. However, it is possible to place two or more cathode grids 10 according to the invention under one anode, or a single cathode grid 10 under several anodes, for example under two anodes arranged side-by-side in a cell, or under several anodes aligned lengthwise along a cell.
The plates 11 and 12 are made of a material resisting the conditions encountered in an aluminium production cell, in particular the materials should be resistant to molten aluminium and preferably also to the cryolite or other molten halide electrolyte. The outer surface at least of the plates 11 and 12 will preferably be made of a material wettable by molten aluminium, such as titanium diboride or another aluminium-wettable refractory material including composite materials based on titanium diboride and other refractory borides. Such refractory borides are dense materials, which means that the grid 10 has a density such that it will settle and remain stable on the cell bottom.
If however the plates 11 and 12 are made of a less-dense material such as a composite formed of carbon or a carbon based material coated with refractory boride, it may be necessary to include an internal ballast in the walls 11, 12, for instance inner steel inserts. Or it is possible to fill one or more of the openings 13 entirely or partly with a suitable dense material. Alternatively, it would be possible to provide means for holding the grids on the cell bottom, allowing the grids to be removed when necessary.
Examples of walls 21, 22 are shown in FIGS. 2a and 2b. Wall 21 of FIG. 2a has slots 25 in one of its long edges. Apertures 14 are provided between the ends of slots 25 in its edge which will rest on the cell bottom. Several of these walls 21 arranged parallel to one another can be assembled by fitting similar walls, disposed transversely, by interengagement of their slots 25, i.e. with the transverse walls placed upside down in relation to FIG. 2a. The top edges of the transverse walls preferably do not have recesses like the apertures 14.
FIG. 2b shows a wall 25 with slots 26 in its upper edge for receiving transverse plates which may be held above the cell bottom by a height h, thus allowing for circulation of the aluminium pool.
The grid 10 can rest directly on the cell bottom with the bottom edges of its plates 11, 12 on the cell bottoms, in which case apertures such as apertures 14 are provided to allow the molten aluminium to freely penetrate in the openings 13 within the grid, or it is possible for the grid 10 to be fitted with feet on which it stands, or the grid 10 may rest on beams or walls extending across the cell bottom and which allow a space for molten aluminium to penetrate in the bottom of the grid 10.
The intersecting walls can be held together solely by a tight fit of the interengaging slots, or they can be welded together or secured by any suitable means. It is also possible to make each grid with intersecting walls as a single piece.
With reference to FIG. 3, a grid 10 of the invention, made of walls 11 and 12, is illustrated on a cell bottom 30 of an aluminium production cell, shown only in part. The cell bottom 30 is for instance made of carbon and is coated with a refractory coating 31, for example a titanium diboride based coating as described in WO 93/20026. Such coating prevents sodium penetration in the carbon cell bottom 30 and, most important, prevents deformation of the cell bottom 30. Also, particularly in the areas of the cell bottom 30 outside the grids 10, such coating improves the resistance of the cell bottom to wear by movements of sludge.
In this example, the grid 10 is immersed in the cathodic pool of molten aluminium 32, and normally remains permanently below the surface of the molten aluminium 32 and therefore does not normally contact the molten cryolite or other molten halide electrolyte 33. Above the grid 10, an anode 34 dips into the molten electrolyte 33. As shown, the grid 10 may be about the same size as the facing anode 34, but it could be somewhat smaller or larger, and may be of the same or different shape in plan view.
In this embodiment, the grid 10 serves to restrain movements in the pool of molten aluminium 32. By stabilizing the pool 32, ripples on the surface are minimized and the anode-cathode interelectrode space can be maintained at a small and approximately constant value, using standard consumable pre-baked carbon anodes or, preferably, using dimensionally stable anodes.
The required number of grids 10 can be installed in place on the cell bottom 30 when starting up the cell as the cell contents melt, or during operation while the cell contents are already molten.
The described grids 10 made of intersecting walls are mechanically strong, easy to place on the cell bottom 30, remain firmly in place during operation, and can withstand the cell conditions for long periods of time without disintegrating. Such grids remain mechanically strong even after long periods of service, and they can without great difficulty be lifted from the cell during operation for servicing or replacement.
FIG. 4 shows another embodiment with a grid 10 having inclined top cathode-forming edges 44 which face a corresponding inclined lower face 35 of anode 34. This grid 10 comprises trapezoidal plates 41 each having a rectangular bottom part and an inclined top edge 44. Transverse walls 42 may extend to height 43, just above, at the same level as, or below the usual level of the surface of aluminium pool 32.
The angle of inclination of the anode face 35, and the cathode-forming edge 44 of grid 10, is usually from about 3° to about 15° from horizontal in order to ensure an effective removal of the anodically-generated gases, as indicated by the arrows, thereby avoiding "bubble effects" on the lower anode face, especially when the anodes 34 are prebaked carbon anodes.
In this embodiment, the inclined top parts 44 of the walls 41 of grid 10 protrude above the top surface of the aluminium pool 32, in the molten electrolyte 33. Thus, these inclined top parts 44 of grid 10 form a drained cathode from which the product aluminium drains into the pool 32 which is stabilized by being held inside the openings 13 in grid 10. Movements of the aluminium pool 32 between the grids 10 is also restrained due to the presence of these grids.
Because these top parts 44 of the grids 10 are exposed both to the molten aluminium 32 and the molten electrolyte 33, these parts are subjected to a more aggressive environment than for embodiments where the grid 10 remains under the cathodic aluminium 32. Consequently, the lifetime of such cathode-forming grids is not so great. However, it is relatively easy to monitor wear or degradation of the exposed cathode-forming top parts 44 of the grids, and remove and replace an entire grid 10 when necessary or when desired to optimize cell performance.
FIG. 5 illustrates another type of grid-like assembly 10 made up of several tubular pieces 50 connected together. The illustrated assembly is made up of a cluster of four octagonal tubular pieces 50 joined together by facing sides 51, leaving a central opening 52 of square section. The facing sides 51 can be secured together, e.g. by welding, or they could have interengaging shapes, or both. The bottom edges of pieces 50 have apertures for passage of molten aluminium. This cluster can be extended by adding on further pairs of tubular pieces in either or both directions to form an assembly of the desired shape and dimensions.
FIG. 6 shows another cathode grid 10 cooperating with anode plates. This grid comprises intersecting vertical plates 61 and 62 which rest on a cell bottom 66. The plates 61 are just over half of the height of plates 2. In their lower edges the plates 62 have apertures 64, below the level if a molten aluminium pool 72.
Mid-way between the grid's vertical plates 62, the top edges of plates 61 have recesses 65 serving as guides which receive the lower ends of a series of anode plates 74 suspended parallel to one another by means not shown.
The upper ends of the grid's cathode plates 62 protrude above the aluminium pool 72 into a molten cryolite or other molten halide electrolyte 63, so that electrolysis can take place between the bottom parts of anode plates 74 and the facing top parts of cathode plates 62. These protruding upper ends of cathode plates 62 are made of or coated with aluminium-wettable material such as titanium diboride.
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A cell for the production of aluminium by the electrolysis of a molten electrolyte, in particular the electrolysis of alumina dissolved in a molten halide electrolyte such as cryolite, comprises anodes immersed in the molten electrolyte above a cell bottom whereon molten product aluminium is collected in a pool containing bodies of aluminium-resistant material. Under the anodes is at least one grid (10) of side-by-side upright or inclined walls (11,12) of aluminium-resistant material whose bottom ends stand on a ceramic-coated carbon cell bottom covered by the pool of molten aluminium. The bottom ends of the grid walls form a base which is large compared to the height of the walls, each grid (10) standing on the cell bottom and being removable from the cell. These grids reduce movements in the aluminium pool and their top parts may act as a drained cathode.
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BACKGROUND OF THE INVENTION
The lymphokine, Macrophage Migration Inhibition Factor (MIF), has been identified as a mediator of the function of macrophages in host defence and its expression correlates with delayed hypersensitivity and cellular immunity. A 12,000 da protein with MIF activity was identified by Weiser et al, Proc. Natl. Acad. Sci. U.S.A., 86, 7522-7526 (1989). MIF was first characterized by expression cloning from activated human T-cells, however, the abundance of the product is low in these cells. No MIF protein is commercially available, although the human cDNA is marketed by R&D Systems Inc., Minneapolis, Minn.
The eye lens contains high concentrations of soluble proteins, Harding et al, The Eye, ed. Davson, H., Academic Press, New York, Vol. 1B, pp 207-492; Wistow et al, Ann. Rev. Biochem., 57, 479-504 (1988); and Histow et al, Nature, 326, 622-624 (1987).
The most abundant proteins, the crystallins, are structural, comprising the refractive material of the tissue. Some crystallins are specialized for the lens, others are identical to enzymes expressed in lower amounts in other tissues. Individual crystallins may account for a quarter or more of total lens protein, Wistow et al, Nature, 326, 622-624 (1987) and Wistow et al, PNAS, 87, 6277-6280 (1990). However, other proteins are also present at moderate abundance, typically in the range 0.1-1% of total protein. Some of these are also enzymes, such as α-enolase or aldehyde dehydrogenase, found as crystallins in some species, Wistow et al, J. Mol. Evol., 32, 262-269 (1991).
SUMMARY OF THE INVENTION
It has been discovered that a moderately abundant protein in the eye lens, "10 K protein", which accounts for as much as 1% of total protein in young or embryonic lenses is similar to MIF. An equivalent protein is present in all lenses examined, including bovine lenses from slaughtered animals. Accordingly, eye lenses of various animals, especially birds and mammals, can be used as a source of MIF.
MIF is extremely abundant in lens compared with other known sources. Proteins accumulate to high levels in lens, which has low proteolytic activity. Lenses may be removed from eyes quickly and simply with one incision. Moreover, no other abundant lens proteins are close to lens MIF in size, thus facilitating its separation. Lenses can similarly be used as abundant sources of active enzymes including lactate dehydrogenase B and argininosuccinate lyase.
The lens MIF can be obtained by homogenizing ocular lens to form a homogenate, separating a soluble extract and an insoluble membrane fraction from said homogenate and recovering purified MIF from said soluble extract.
The present invention is also directed to purified lens MIF. In preparing the purified natural lens MIF of the present invention, a stimulant such as Con-A is not added to the preparation and therefore this possible source of contamination is avoided.
MIF plays an important role in the inflammatory response. Lenses could become a useful source of MIF protein for research and therapeutic purposes. In lens, MIF expression is associated with cell differentiation and with expression of the proto-oncogene N-myc. Lens MIF may be a growth factor in addition to its role as a lymphokine. Like other lymphokines, such as IL-2, MIF could have specific therapeutic value in stimulation of immune system and other cells. In particular, lens MIF may play a role in some inflammatory conditions in the eye. MIF isolated from lens could be modified to derive antagonists for the inflammatory process.
The MIF of the present invention can be produced by recombinant DNA techniques. The invention therefore is also directed to recombinant DNA which encodes MIF, replicable expression vectors which contain the DNA and which can express MIF and transformed cells and/or microorganisms which contain the DNA and which can express large amounts of MIF.
DETAILED DESCRIPTION OF THE INVENTION
The MIF can be separated from the lens by a variety of different procedures.
As a first step, the lens should be homogenized in an aqueous solution, preferably an aqueous buffered solution having a pH of about 7 to 7.6, preferably 7 to 7.4 which does not adversely affect the MIF, in order to allow the soluble materials to dissolve in the buffer. The buffered solution will usually not contain any other solvents. Homogenization is preferably achieved by physically breaking up the lenses by use of a glass rod, blender or other suitable devices or procedures. The volume ratio of lens to the solution is usually 1:1 to 5, preferably 1:1.5 to 3 (v/v).
After the lens is homogenized, the insoluble membranes are separated from the aqueous solution containing the soluble extract. This can be accomplished in any known manner but centrifugation appears to be especially useful.
The MIF is then recovered from the soluble extract. In the experiments reported herein, this is accomplished by subjecting the soluble extract to sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE). However, if it is desired to separate the MIF from the soluble extract on a larger scale, various procedures such as column chromatography (sizing columns) and/or isoelectric focusing can be utilized.
All lenses examined by SDS polyacrylamide gel electrophoresis have a prominent minor band with subunit size around 10-12 kDa, "10 K protein" MIF . is the major component in the 10-12,000 da subunit size range, as visualized by SDS polyacrylamide gel electrophoresis. In aged and cataractous lenses, fragments of α-crystallin have been found in this size range, Harding et al, The Eye, ed. Davson, H. (Academic Press, New York), Vol. 1B, pp. 207-492 (1984). However, even embryonic lenses, in which proteolysis is unlikely to have occurred to a great extent, have a distinct 10 K subunit band. This band was isolated from embryonic chick lens and sequenced. Surprisingly, the sequence obtained showed close identity to a recently described lymphokine, human MIF, Weiser et al, Proc. Natl. Acad. Sci. U.S.A., 86, 7522-7526 (1989). The polymerase chain reaction (PCR) was used to clone the mRNA for chick lens 10 K protein. This provided a probe to clone cDNA for chick and three week old mouse lens 10 K protein. PCR was also used to clone 10 K protein from fetal human lens.
The presence of MIF at high levels in hens suggests it may have a wide role as a polypeptide growth factor rather than a restricted function as a lymphokine. Preliminary experiments using PCR suggest that MIF in embryonic chick lens is expressed in equatorial and fiber cells but not in central epithelium, consistent with a role in the differentiation of lens cells. Northern blot analysis with the cDNA for mouse lens 10 K/MIF shows that the message is present in various tissues, including lens, brain and kidney.
The present invention is also directed to a vector comprising a replicable vector and a DNA sequence encoding the MIF inserted into the vector. The vector may be an expression vector and is conveniently a plasmid.
The MIF preferably comprises one of the sequences described in the SEQUENCE LISTING or a homologous variant of said MIF having 5 or less conservative amino acid changes, preferably 3 or less conservative amino acid changes. In this context, "conservative amino acid changes" are substitutions of one amino acid by another amino acid wherein the charge and polarity of the two amino acids are not fundamentally different. Amino acids can be divided into the following four groups: (1) acidic amino acids, (2) neutral polar amino acids, (3) neutral non-polar amino acids and (4) basic amino acids. Conservative amino acid changes can be made by substituting one amino acid within a group by another amino acid within the same group. Representative amino acids within these groups include, but are not limited to, (1) acidic amino acids such as aspartic acid and glutamic acid, (2) neutral polar amino acids such as valine, isoleucine and leucine, (3) neutral non-polar amino acids such as asparganine and glutamine and (4) basic amino acids such as lysine, arginine and histidine.
In addition to the above mentioned substitutions, the MIF of the present invention may comprise the specific amino acid sequences shown in the SEQUENCE LISTING and additional sequences at the N-terminal end, C-terminal end or in the middle thereof. The "gene" or nucleotide sequence may have similar substitutions which allow it to code for the corresponding MIF.
In processes for the synthesis of the MIF, DNA which encodes the MIF is ligated into a replicable (reproducible) vector, the vector is used to transformhost cells, and the MIF is recovered from the culture. The host cells for the above-described vectors include prokaryotic microorganisms including gram-negative bacteria such as E. coli, gram-positive bacteria, and eukaryotic cells such as yeast and mammalian cells. Suitable replicable vectors will be selected depending upon the particular host cell chosen. Alternatively, the DNA can be incorporated into the chromosomes of the eukaryotic cells for expression by known techniques. Thus, the present invention is also directed to recombinant DNA, recombinant expression vectors and transformed cells which are capable of expressing MIF.
For pharmaceutical uses, the MIF is purified, preferably to homogeneity, and then mixed with a compatible pharmaceutically acceptable carrier or diluent. The pharmaceutically acceptable carrier can be a solid or liquid carrier depending upon the desired mode of administration to a patient. If the MIF is used to stimulate growth or differentiation of cells, specifically mammalian or bird cells, the MIF is contacted with the cells under conditions which allow the MIF to stimulate growth or differentiation of the cells. MIF could be administered to stimulate macrophages, which might be useful under some circumstances. For suppression of inflammation, macrophages would need to be unstimulated, this might be achievable using modified MIF as an antagonist.
EXAMPLE 1
Lenses: Chick lenses were excised from 11 day post fertilization embryos. Mouse lenses were from 3 week old BALB/C mice. Human fetal lenses were from a 13.5 week fetus obtained in therapeutic abortion in 1986 and saved at -80° C. Bovine lenses were obtained from approximately 1 year-old animals from slaughter.
Lens Protein: For protein analysis, lenses were homogenized with a Teflon tipped rod in Eppendorf tubes (1.5 ml) in TE buffer (10 mM Tris-HCl, pH 7.3; 1 mM EDTA) in an amount of about 1:2 (v/v). Membranes were spun down by microcentrifugation and the soluble extract retained. Proteins were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis, using 15% acrylamide, 1% SDS, Laemmli, Nature, 227, 680-685 (1970). Loading buffer contained 1 mM mercaptoethanol. For sequencing, gels were electroblotted onto nitrocellulose. The 10 K band was excised. The Harvard Microchemistry facility performed microsequencing as a service, as described before, Wistow et al, J. Cell Biol., 107, 2729-2736 (1988). The protein was digested off the nitrocellulose by trypsin. Peptides were separated by HPLC and the major peaks sequenced using an Applied Biosystems automated sequencer. An initial N-terminal sequence was obtained by direct microsequencing of a fragment eluted from a coomassie blue stained gel slice.
Computer analysis: Sequences were compared with the translated GenBank database, v65 using the SEQFT program of the IDEAS package, Kanehisa, IDEAS User's Manual (Frederick Cancer Research Facility, Frederick, Md.) (1986), run on the CRAY XMP at the Advanced Scientific Computing Laboratory, Frederick, Md.
RNA Preparation and Analysis: Chick, mouse and human lenses and other tissues were homogenized in RNAzol (Cinna/Biotecx, Friendswood, Tex.) and subjected to PA extraction, Chomczynski et al, Anal. Biochem., 162, 156-159 (1987). RNA was quantitated by UV absorption. For Northern blots, equal amounts of RNA were run on formaldehyde gels, Davis et al, Basic Methods in Molecular Biology, Elsevier Science Publishing Co., New York, N.Y. (1986) and electroblotted onto nitrocellulose or nylon membranes, Towbin et al, Proc. Natl. Acad. Sci. U.S.A., 76, 4350-4354 (1979).
PCR: Oligonucleotides were designed from the sequence of chick lens 10 K protein peptides and from the sequence of human MIF. Bam HI and Sal I sites were incorporated as shown. oligo sequences: ##STR1##
Chick and human lens RNA were amplified using one step of the reverse transcriptase reaction primed with either 3' or oligo dT primers, Innis et al, PCR Protocols, A Guide to Methods and Applications, Academic Press, Inc., New York, N.Y., 1st Ed. (1990). First strand cDNA was then amplified by 30 cycles of PCR using an annealing temperature of 55° C. Product was visualized using 1% agarose gels and ethidium bromide staining.
CDNA cloning and Sequencing: The 300 bp chick lens cDNA PCR product was subcloned in Bluescript II (Stratagene, La Jolla, Calif.) following digestion with Bam HI and Sal I. A Bam HI site in the chick sequence resulted in two fragments which were cloned separately. Multiple clones were sequenced using Sequenase reagents (USB, Cleveland, Ohio) and 35 S-dATP label (Amersham, Arlington Hts., Ill.). The human lens PCR product was subcloned as a single Bam HI-Sal I fragment and sequenced. The chick PCR product was also used as a probe by labelling with 32 P-dCTP and random priming using a kit from Bethesda Research Laboratory, Gaithersburg, Md. This was used to screen an embryonic chick lens cDNA library in λgt11 (Clontech, Palo Alto, Calif.) and a newborn mouse lens library in λzap (vector from Stratagene, library a gift from Joan McDermott, NEI). Clones were screened, purified and sequenced by standard methods, Davis et al, Basic Methods in Molecular Biology, Elsevier Science Publishing Co., New York, N.Y. (1986).
The partial cDNA sequences obtained are as follows: ##STR2##
Protein sequence: Microsequence for 5 tryptic peptides of chick lens MIF and an N-terminal sequence were obtained and are shown in Table 1.
The four sequences compared are: ##STR3##
TABLE 1__________________________________________________________________________T-Cell MIF MPMFIVNTNVPRASVPDGFLSELTQQLAQATGKPPQYIAVHVVPDQLMAFGGSS :::::::::::::::::::::::::::::::::::::::::::Mouse lens 10K VNTNVPRASVPEGFLSELTQQLAQATGKPAQYIAVHVVPDQLMTFSGTN :::::::::::::::::::::::::::::::Chick lens 10k :::::::::::::::::::::::::::::::Human lens 10k VPRASVPDGFLSELTQQLAQATGKPPQYIAVHVVPDQLMAFGGSS ##STR4##::::::::::::::::::::::::::::::::::::::::::::::::::::::DPCALCSLHSIGKIGGAQNRNYSKLLCGLLSDRLHISPDRVYINYYDMNAANVGWNGSTFA::::::::::::::::::::::::::::::::::::::::::::: ##STR5##:::::::::::::::::::::::::::::::::::::EPCALCSLHSIGKIGGAQNRSYSKLLCGLLAERLRISPDRVYINYYDMNAANV__________________________________________________________________________
Deduced sequences of 10 K/MIF proteins shown in Table 1. Human T-cell MIF is from Weiser et al, Proc. Natl. Acad. Sci. U.S.A., 86, 7522-7526 (1989). Lens sequences are from cDNA library and PCR derived clones. Parts of the human lens 10 K sequence were derived from the PCR oligos and are not shown. Peptides of chicken 10 K/MIF are indicated by underline. The asterisk (*) shows the only difference between human lens and T-cell sequences.
The N-terminus of the lens 10 K protein is at least partly unblocked. All sequences gave a partial match with the sequence of human MIF cloned from activated T-cells, Weiser et al, Proc. Natl. Acad. Sci. U.S.A., 86, 7522-7526 (1989). Sequences deduced from PCR and cDNA library clones confirmed this relationship. PCR clones for the coding region of human lens 10 K protein were identical in sequence to the published sequence of human T-cell MIF except for one base identical in different PCR clones. Different PCR clones confirmed the difference. This single base change alters a predicted Serine residue to Asparagine, the identical amino acid found at the same position in mouse and chick cDNA clones and in chick protein sequence. It is possible that this conservative difference with the T-cell sequence results from conservative polymorphism or cloning or sequencing artifact. Such a change may or may not significantly change the properties of the protein. Distribution of 10 K/MIF: PCR of RNA from dissected central epithelium, equatorial epithelium and fiber cells from 6, 12 and 14-day chick embryos showed that RNA for 10 K/MIF is present in equatorial and fiber cells at all stages but is absent from the central epithelium. Protein gels also confirm that 10 K protein is detectable from 6 days and throughout chick lens development. A similar band is seen in all species examined, including bovine lenses. Northern blot analysis of mouse tissues using a mouse cDNA probe, show that 10 K/MIF RNA is present in several tissues in addition to lens, particularly in brain and kidney.
EXAMPLE 2
The mouse cDNA is subcloned into a eukaryotic expression vector, pMAMNeo. PCR with added linker sequences is utilized to accomplish this so that a complete mouse MIF will be produced from its own initiator ATG in mammalian cells such as COS or NIH 3T3 cells.
EXAMPLE 3
The same clone of Example 2 is inserted into prokaryotic expression vector pKK233-2 to produce mouse MIF in E. coli.
__________________________________________________________________________SEQUENCE LISTING(1) GENERAL INFORMATION:(iii) NUMBER OF SEQUENCES: 10(2) INFORMATION FOR SEQ ID NO:1:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 295 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: cDNA(ix) FEATURE:(A) NAME/KEY: CDS(B) LOCATION: 2..295(xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:CGTGCCCCGCGCCTCCGTGCCGGACGGGTTCCTCTCCGAGCTCACC46ValProArgAlaSerValProAspGlyPheLeuSerGluLeuThr15 1015CAGCAGCTGGCGCAGGCCACCGGCAAGCCCCCCCAGTACATCGCGGTG94GlnGlnLeuAlaGlnAlaThrGlyLysProProGlnTyrIleAlaVal20 2530CACGTGGTCCCGGACCAGCTCATGGCCTTCGGCGGCTCCAGCGAGCCG142HisValValProAspGlnLeuMetAlaPheGlyGlySerSerGluPro35 4045TGCGCGCTCTGCAGCCTGCACAGCATCGGCAAGATCGGCGGCGCGCAG190CysAlaLeuCysSerLeuHisSerIleGlyLysIleGlyGlyAlaGln50 5560AACCGCTCCTACAGCAAGCTGCTGTGCGGCCTGCTGGCCGAGCGCCTG238AsnArgSerTyrSerLysLeuLeuCysGlyLeuLeuAlaGluArgLeu6570 75CGCATCAGCCCGGACAGGGTCTACATCAACTATTACGACATGAACGCG286ArgIleSerProAspArgValTyrIleAsnTyrTyrAspMetAsnAla8085 9095GCCAATGTG295AlaAsnVal(2) INFORMATION FOR SEQ ID NO:2:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 98 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:ValProArgAlaSerValProAspGlyPheLeuSerGluLeuThrGln151015GlnLeuAlaGlnAlaThrGlyLysProProGlnTyrIle AlaValHis202530ValValProAspGlnLeuMetAlaPheGlyGlySerSerGluProCys354045AlaLeu CysSerLeuHisSerIleGlyLysIleGlyGlyAlaGlnAsn505560ArgSerTyrSerLysLeuLeuCysGlyLeuLeuAlaGluArgLeuArg6570 7580IleSerProAspArgValTyrIleAsnTyrTyrAspMetAsnAlaAla859095AsnVal(2) INFORMATION FOR SEQ ID NO:3:(i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 459 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: cDNA(ix) FEATURE:(A) NAME/KEY: CDS(B) LOCATION: 1..330(xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:GTGAACACCAATGTTCCCCGCGCCTCCGTGCCAGAGGGGT TTCTGTCG48ValAsnThrAsnValProArgAlaSerValProGluGlyPheLeuSer151015GAGCTCACCCAGCAGCTGGCGCAGGCCACCGGCAAGCCC GCACAGTAC96GluLeuThrGlnGlnLeuAlaGlnAlaThrGlyLysProAlaGlnTyr202530ATCGCAGTGCACGTGGTCCCGGACCAGCTCATGACTTTTAGC GGCACG144IleAlaValHisValValProAspGlnLeuMetThrPheSerGlyThr354045AACGATCCCTGCGCCCTCTGCAGCCTGCACAGCATCGGCAAGATCGG T192AsnAspProCysAlaLeuCysSerLeuHisSerIleGlyLysIleGly505560GGTGCCCAGAACCGCAACTACAGTAAGCTGCTGTGTGGCCTGCTGTCC240 GlyAlaGlnAsnArgAsnTyrSerLysLeuLeuCysGlyLeuLeuSer65707580GATCGCCTGCACATCAGCCCGGACCGGGTCTACATCAACTATTACGAC 288AspArgLeuHisIleSerProAspArgValTyrIleAsnTyrTyrAsp859095ATGAACGCTGCCAACGTGGGCTGGAACGGTTCCACCTTCGCT 330MetAsnAlaAlaAsnValGlyTrpAsnGlySerThrPheAla100105110TGAGTCCTGGCCCCACTTACCTGCACCGCTGTTCTTTGAGCCTCGCTCCACGTAGTGTTC390TGT GTTTATCCACCGGTAGCGATGCCCACCTTCCAGCCGGGAGAAATAAATGGTTTATAA450GAGAAAAAA459(2) INFORMATION FOR SEQ ID NO:4:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 110 amino acids (B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:ValAsnThrAsnValProArgAlaSerValProGluGlyPheLeuSer151015GluLeuThrGlnG lnLeuAlaGlnAlaThrGlyLysProAlaGlnTyr202530IleAlaValHisValValProAspGlnLeuMetThrPheSerGlyThr35 4045AsnAspProCysAlaLeuCysSerLeuHisSerIleGlyLysIleGly505560GlyAlaGlnAsnArgAsnTyrSerLysLeuLeuCysGlyLeuLeu Ser65707580AspArgLeuHisIleSerProAspArgValTyrIleAsnTyrTyrAsp859095Me tAsnAlaAlaAsnValGlyTrpAsnGlySerThrPheAla100105110(2) INFORMATION FOR SEQ ID NO:5:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 292 base pairs(B) TYPE: nucleic acid(C) STRANDEDNESS: single (D) TOPOLOGY: linear(ii) MOLECULE TYPE: cDNA(ix) FEATURE:(A) NAME/KEY: CDS(B) LOCATION: 2..292(xi) SEQUENCE DESCRIPTION: SEQ ID NO:5:CGTCTGCAAGGACGCCGTGCCCGACAGCCTGCTGGGCGAGCTGACC46ValCysLysAspAlaValProAspSerLe uLeuGlyGluLeuThr151015CAGCAGCTGGCCAAGGCCACCGGCAAGCCCGCGCAGTACATAGCCGTG94GlnGlnLeuAlaLysAlaThrGlyLysPro AlaGlnTyrIleAlaVal202530CACATCGTACCTGATCAGATGATGTCCTTGGGCTCCACGGATCCTTGC142HisIleValProAspGlnMetMetSerLe uGlySerThrAspProCys354045GCTCTCTGCAGCCTCTACAGCATTGGCAAAATTGGAGGGCAGCAGAAC190AlaLeuCysSerLeuTyrSerIleGlyLysI leGlyGlyGlnGlnAsn505560AAGACCTACACCAAGCTCCTGTGCGATATGATTGCGAAGCACTTGCAC238LysThrTyrThrLysLeuLeuCysAspMetIleAla LysHisLeuHis657075GTGTCTGCAGACAGGGTATACATCAACTACTTCGACATAAACGCTGCC286ValSerAlaAspArgValTyrIleAsnTyrPheAspIleAsnAla Ala80859095AACGTG292AsnVal(2) INFORMATION FOR SEQ ID NO:6:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 97 amino acids (B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(xi) SEQUENCE DESCRIPTION: SEQ ID NO:6:ValCysLysAspAlaValProAspSerLeuLeuGlyGluLeuThrGln151015GlnLeu AlaLysAlaThrGlyLysProAlaGlnTyrIleAlaValHis202530IleValProAspGlnMetMetSerLeuGlySerThrAspProCysAla35 4045LeuCysSerLeuTyrSerIleGlyLysIleGlyGlyGlnGlnAsnLys505560ThrTyrThrLysLeuLeuCysAspMetIleAlaLysHi sLeuHisVal65707580SerAlaAspArgValTyrIleAsnTyrPheAspIleAsnAlaAlaAsn8590 95Val(2) INFORMATION FOR SEQ ID NO:7:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 115 amino acids(B) TYPE: amino acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(xi) SEQUENCE DESCRIPTION: SEQ ID NO:7:MetProMetPheIleValAsnThrAsnValProArgAlaSer ValPro151015AspGlyPheLeuSerGluLeuThrGlnGlnLeuAlaGlnAlaThrGly2025 30LysProProGlnTyrIleAlaValHisValValProAspGlnLeuMet354045AlaPheGlyGlySerSerGluProCysAlaLeuCysSerLeuHis Ser505560IleGlyLysIleGlyGlyAlaGlnAsnArgSerTyrSerLysLeuLeu65707580 CysGlyLeuLeuAlaGluArgLeuArgIleSerProAspArgValTyr859095IleAsnTyrTyrAspMetAsnAlaAlaSerValGlyTrpAsnAs nSer100105110ThrPheAla115(2) INFORMATION FOR SEQ ID NO:8:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 110 amino acids(B) TYPE: amino acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(xi) SEQUENCE DESCRIPTION: SEQ ID NO:8:ValAsnThrAsnValProArgAlaSerValProGluGlyPheLeuSer151015GluLeuThrGlnGlnLeuAl aGlnAlaThrGlyLysProAlaGlnTyr202530IleAlaValHisValValProAspGlnLeuMetThrPheSerGlyThr35 4045AsnAspProCysAlaLeuCysSerLeuHisSerIleGlyLysIleGly505560GlyAlaGlnAsnArgAsnTyrSerLysLeuLe uCysGlyLeuLeuSer65707580AspArgLeuHisIleSerProAspArgValTyrIleAsnTyrTyrAsp85 9095MetAsnAlaAlaAsnValGlyTrpAsnGlySerThrPheAla100105110(2) INFORMATION FOR SEQ ID NO:9:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 114 amino acids (B) TYPE: amino acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(xi) SEQUENCE DESCRIPTION: SEQ ID NO:9:ProMetPheIleIleHisThrAsnValCysLysAspAlaValProAsp1510 15SerLeuLeuGlyGluLeuThrGlnGlnLeuAlaLysAlaThrGlyLys202530ProAlaGlnTyrIleAlaValHisIleValProAsp GlnMetMetSer354045LeuGlyGlySerThrAspProCysAlaLeuCysSerLeuTyrSerIle505560 GlyLysIleGlyGlyGlnGlnAsnLysThrTyrThrLysLeuLeuCys65707580AspMetIleAlaLysHisLeuHisValSerAlaAspArgVal TyrIle859095AsnTyrPheAspIleAsnAlaAlaAsnValGlyTrpAsnAsnSerThr100105 110PheAla(2) INFORMATION FOR SEQ ID NO:10:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 98 amino acids(B) TYPE: amino acid(C) STRANDEDNESS: single(D) TOPOLOGY: linear(ii) MOLECULE TYPE: protein(xi) SEQUENCE DESCRIPTION: SEQ ID NO:10:ValProArgAlaSerValProAspGlyPheLeuS erGluLeuThrGln151015GlnLeuAlaGlnAlaThrGlyLysProProGlnTyrIleAlaValHis2025 30ValValProAspGlnLeuMetAlaPheGlyGlySerSerGluProCys354045AlaLeuCysSerLeuHisSerIleGlyLysIleGlyG lyAlaGlnAsn505560ArgSerTyrSerLysLeuLeuCysGlyLeuLeuAlaGluArgLeuArg657075 80IleSerProAspArgValTyrIleAsnTyrTyrAspMetAsnAlaAla859095AsnVal
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Macrophage Migration Inhibition Factor (MIF) can be obtained from ocular lens of various birds and mammals. The amino acid sequences of lens MIF from mice, chickens and humans has been determined and the corresponding cDNA has been cloned.
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BACKGROUND OF THE INVENTION
In electronic prepress systems, digital images are processed in a rasterization image processor (RIP) and output onto film, paper, plate, or other image receiving materials by imagesetters, digital proofers, printers, platesetters, and other such output devices. When outputting color separations or other slices or layers of a digital image to be subsequently superimposed together, geometric accuracy and repeatability is highly desirable. However, fluctuations in ambient operating conditions of the output device and condition sensitive characteristics of the image receiving material render a repeatable output difficult to attain. The operating conditions tend to vary in temperature and humidity which can result in thermal expansion and moisture absorption in the material, and can also effect the exposure sensitivity of the emulsion coating on the material. Thermal expansion and moisture absorption before imaging causes the overall size of the output image to appear larger or smaller than the digital image delivered from the RIP when the material returns to its original condition after imaging. Shifts in the exposure sensitivity can over expose or under expose the output image. These changes to the material can cause noticeable misregistration for separations which are run in different operating conditions, even from the same output device.
To obtain accurate and repeatable output from typical output devices, separation are usually done consecutively from the same output device. Some output devices are equipped with temperature and/or humidity control systems to ensure consistent output. With imagesetting conditions controlled, output of separations may be more accurate, even when run at different times. However, such control systems usually are offered as an upgrade option and add considerable expense to an output device.
Accordingly, it is a general object of the invention to achieve repeatable output of a digital image from an output device such as an imagesetter, digital proofer, or platesetter.
It is an object of the invention to provide an improved digital image output device with a system for correcting for varying operating conditions that effect condition sensitive characteristics of an image receiving material used in the output device.
It is a specific object of the invention to compensate for thermal expansion and contraction of an image receiving material in a digital image output device to output a consistent image size.
It is a specific object of the invention to compensate for thermal expansion and contraction of an image receiving material in a digital image output device to output a consistent image size.
It is a specific object of the invention to compensate for moisture absorption of an image receiving material in a digital image output device to output a consistent image shape.
Platesetters are particularly sensitive to misregistration problems due to output operating conditions. The image receiving material in a platesetter is a plate material onto which a color separation of an image is directly exposed, subsequently processed, and then mounted directly onto a press cylinder of a printing press. Inaccuracies in image size and exposure levels increase make-ready time on the press and increase material waste. It is therefore an object of the invention to output separations of a digital image onto a plate material from a platesetting device consistent in overall size and exposure levels when mounted on a printing press.
SUMMARY OF THE INVENTION
A method and apparatus according to the invention produces a repeatable output image on an image receiving material from digital image data. The method comprises sensing the condition of an image receiving material to be imaged with a digital image, adjusting the output of the digital image according to the condition of the image receiving material to compensate for changes of condition sensitive characteristics of the image receiving material, and outputting the digital image on the image receiving material in accordance with the adjusted output. The invention is applicable wherein the conditions are temperature and humidity and the condition sensitive characteristics are geometric size, shape, and exposure sensitivity of the image receiving material.
One aspect of the invention is related to outputting the digital image on the image receiving material. This includes scanning an exposure beam on the image receiving material while modulating the exposure beam according to the digital image data, and adjusting the exposure level of the exposure beam according to the temperature of the image receiving material to compensate for shifts in exposure sensitivity of the image receiving material.
Another embodiment of the invention includes scanning the exposure beam on the image receiving material while modulating the exposure beam according to the digital image data, and adjusting the modulation frequency and/or scanning speed of the exposure beam in accordance with the surrounding conditions to compensate for changes in geometric size and shape of the image receiving material.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view of an output device such as a platesetter having a condition sensitive control unit according to the invention.
FIG. 2 is an exaggerated illustrative view depicting a condition sensitive characteristic of an image receiving material and resulting output of the output device as in FIG. 1 according to the present invention.
FIG. 3 shows a block diagram depicting a RIP and the output device according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, an output device generally indicated by reference numeral 10 is shown for outputting a digital image onto an image receiving material 12. The output device 10 comprises a scanning mechanism generally indicated by reference numeral 14, a control unit 16, and a material support 18. The scanning mechanism is mounted to a carriage 20 which travels linearly in the slow scan direction along axis C--C, to provide relative movement between the carriage 20 and the material support 18. An exposure beam source 22 generates an exposure beam 24 that is directed through a focus lens 26 onto a beam deflector 28, which deflects the beam 24 to the image receiving material 12. The beam deflector 28 is rotated by a spin motor 30 to scan the beam 24 in the fast scan direction across the image receiving material 12 while the exposure beam source 22 is modulated according to the digital image data supplied to the output device control unit 16 from a RIP (not shown in FIG. 1). The motion of the carriage 20 along the axis C--C is synchronized with the spin motor 30 to line-wise scan the modulated beam 24, producing the output image on the receiving material 12.
Shown in FIG. 2 is an example of thermal expansion of an image receiving material in the preferred printing plate form according to the invention. Plate A is at temperature T 1 and humidity H 1 and is shown supported on the material support 18 and is registered with respect thereto by four reference points 32-38. The registration system can be electronic or mechanical as such systems are known in the art for positioning each plate in a known position with respect to the material support and the scanning mechanism. Plate A has an image area I representing the size of the image to be output to the plate according to the digital image data. Thermally expanded plate A' is at temperature T 2 and humidity H 2 and is also shown (exaggerated for illustrative purposes) having a corresponding expanded image area I'. The expanded image area I' represents the size of the output image for the expanded plate A'. Plate A and thermally expanded Plate A' are the same image receiving material but have different geometric sizes due to a difference in their respective temperatures and/or humidities. The controller unit 16 determines the output size in a manner to be described hereinafter, to ensure that the size of the output image is consistent for a plate at a predetermined temperature, regardless of the temperature of the plate during exposure by the scanning mechanism 14. Ideally, the plate remains in register with respect to the reference points 32-38 whether thermal expansion occurs before, during, or after loading the plate onto the material support 18. FIG. 2 shows the plate registered with respect to two edges of the plate. However, the plate can be registered by other methods such with the center of the plate along a center axis of the material support.
Referring to FIG. 3, the method for determining the size of the output image is illustrated in a block diagram. A RIP 100 delivers image data to the control unit 110 of the output device 120 as original data 130. The output device 120 is a platesetter according to the preferred embodiment of the invention. A condition sensor 140 internal to the output device 120 senses the temperature of the plate and sends an input signal 150 to the control unit 110 indicating the temperature of the plate. The control unit 110 is programmed to adjust the size of the output image according to the temperature of the image plate and the coefficient of thermal expansion of the plate material, given by the equation a'=(1 dL)/(L dT) where a' denotes the coefficient of expansion, L length of the plate material, A area, and T temperature. The equations for expansion in length and area are given by ΔL=a'LΔT, and ΔA=2a'AΔT for linear expansion of a homogeneous material. (It will be appreciated that non-linear expansions are taken into consideration and the above formulas are given as an example and are not intended to limit the invention.) As there are standard plate sizes and materials typically used in the platesetter, the expanded plate sizes within a temperature range can be calculated for each standard plate size and material, and programmed into the memory of the control unit. The input signal 150 from the condition sensor 140 directs the control unit 110 to "look-up" the temperature dependent output size for the plate size in use at the sensed plate temperature. The control unit 110 then delivers control commands to the output mechanism 160 as condition dependent data 170, the output mechanism 160 being the scanning mechanism 14 shown in FIG. 1 according to the preferred embodiment of the invention.
The scanning mechanism 14 is normally controlled by the control unit 16 which generates a pixel clock signal for several standard plate sizes at several standard resolutions. The pixel clock signal synchronizes the modulation of the exposure beam 24 and the slow scan and fast scan motors driving the carriage 20 and the beam deflector 28, respectively. For a known standard plate size and a selected output resolution, the pixel clock generates a standard number of pixels per scan line and scan lines per plate, covering the entire standard plate area. To increase the output image size for an expanded plate, the pixel clock frequency is adjusted to spread out the pixels, thereby lengthening the scan line in the fast scan direction and increasing the spacing of the scan lines in the slow scan direction to cover the area of the expanded plate, such as for a plate A' expanded in both the fast scan and slow scan directions in FIG. 2. The beam intensity can also be adjusted to account for spacing changes between scan lines. The pixel clock control commands are combined with the original data 130 from the RIP 100 and delivered to the scanning mechanism 14 as the condition dependent data 160. The resulting output image is uniformly expanded according to the plate temperature and the coefficient of thermal expansion of the plate at the instant of imaging. The position of the image with respect to the plate can be contained in the original data 130, and therefore the output image position and size with respect to the plate remain proportional, as exemplified in FIG. 2.
More frequently the plate expands rather than contracts before imaging as described in the above example. However, it will be understood that decreasing the output image size for a thermally contracted plate is accomplished in a similar manner. It will be appreciated that the material support can support the material is a variety of configurations other than the planar support illustrated in FIG. 2. Other support configurations can be cylindrical in form, such as capstan type supports and internal and external drum supports. Further the support can be of a virtual type configuration rather than a surface.
Some lithographic printing plates chance sensitivity as a function of temperature in a predictable manner. Others can be affected as a function of humidity. The present invention compensates for these condition sensitive characteristics by adjusting the output level of the exposure beam according to the temperature and/or humidity sensed by the condition sensor, thereby preventing over or under exposure of the plate due to changes in the exposure sensitivity. The sensitivity thresholds for certain materials shift in a known manner as a function of temperature and/or humidity. Therefore, the control unit can be programmed with a "look-up" table of information for the various types of plates used in the output device. Then the correct exposure level is "looked-up" by the control unit when an input signal from the condition sensor is received. The control unit delivers the control commands to the scanning mechanism with the condition dependent data, to adjust the power output of the exposure beam source according to the sensitivity threshold for the plate in use at the sensed plate condition. It will be appreciated that the condition dependent data may compensate for thermal expansion of the plate, as heretofore described, in addition to changes due to shifts in exposure sensitivity.
Some materials such as aluminum, tend to expand uniformly and linearly along length and width axes, according to the coefficient of thermal expansion for aluminum. However, other materials have variations in the coefficients of thermal expansion for the different axes. In some plate materials such as polyester, expansion can occur in a non-linear manner with maximum expansion along the diagonal axes of the plate due to moisture absorption. It will be understood that such different properties can be considered when programming the control unit, whether the condition is easily predictable or experimentally measured under varying conditions and recorded in the "look-up" table. Further, whether the changes in size, shape, and exposure sensitivity are uniform or otherwise in response to changes in the temperature, humidity, or both, the memory of the control unit can be programmed to adjust the modulation frequency and exposure level of the exposure source according to the sensed condition in the output device. When multiple condition sensitive characteristics of a material are affected by changes in the ambient conditions, the compensation can be superimposed by the control unit or measured and recorded simultaneously to compensate for variations.
While this invention has been described in terms of a preferred embodiment, those skilled in the art will appreciate that various modifications, substitutions, omissions and changes may be made without departing from the spirit thereof. Accordingly, it is intended that the scope of the present invention be limited solely by the scope of the following claims, including equivalents thereof.
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A platesetting method and apparatus provides for dimensional and/or exposure sensitivity changes in a printing plate to be imaged in a platesetter. A condition sensor senses the temperature of the plate prior to exposure so that a control unit can adjust the control commands to the scanning exposure mechanism of the platesetter in order to compensate for any thermal expansion or exposure sensitivity shifts. An image to be recorded onto the plate material has a standard size at a standard plate material temperature. When the plate material is at a non-standard temperature, as determined by the thermal sensor, a program, stored in memory, calculates a new image size based on the non-standard temperature and the thermal characteristics of the plate material which are also stored in memory. The imagesetter electronic controller then exposes an image having a size which will be the standard size when the plate material returns to the standard temperature.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 61/990,848 filed May 9, 2014, which is incorporated herein in its entirety by reference.
FIELD OF THE INVENTION
The invention generally relates to archery and bow accessories. More specifically, the invention relates to stabilizers, quivers, and combinations thereof.
BACKGROUND OF THE INVENTION
The field of archery is ancient, and the bow has long been a staple of hunting and warfare. In modern times, the tradition of archery continues recreationally and in hunting as most U.S. states designate a bow hunting season for certain animals. As archery has developed through the centuries, new features and accessories have been added to the bow.
One new feature of the modern bow is a stabilizer, which is typically a shaft-like mass that extends forward from the bow. When an arrow is launched from a bow, the arrow is subjected to a sudden propulsive force, and consequently the bow is subjected to a sudden and equal reactive force transmitted through the bow string. Often, this propulsive force is accompanied by a vertical or lateral torque that may cause the arrow to deviate from its desired flight path.
Stabilizers have three purposes for the archer: balance, vibration damping, and making the archer hold the bow steadier while aiming. The balancing goal is to steady a bow in an archer's hand so that it does not noticeably tip to either side or tip overly frontward or backward while aiming. Next, many stabilizers have some form of a vibration damping system to dissipate vibration caused by the released energy during the shot. Lastly, as an archer aims the bow, it is noticeably easier to grip the bow if there is some mass positioned forward of the bow. All else being equal, a stabilizer that extends farther out in front of the bow will make steadier aiming possible as compared to a shorter stabilizer. Further descriptions of a stabilizer may be found in U.S. Pat. Nos. 6,742,723 and 5,992,403, which are hereby incorporated by reference in their entirety.
Another feature of the modern bow is the quiver, which allows an archer to conveniently carry arrows, bolts, or darts. Quivers may be disposed on a belt, slung over the back of the archer, carried in the archer's hand, or carried in the archer's backpack. However, the modern trend is to attach the quiver to the bow itself. An example of such a quiver is described in U.S. Pat. No. 6,105,566, which is hereby incorporated by reference in its entirety.
A bow-mounted quiver has many drawbacks. First, the quiver obstructs the view of the archer. A bow-mounted quiver is vertically oriented and disposed on either side of the bow. This necessarily restricts the view of the archer which can endanger the archer. A bow hunter must stalk his or her target and be in close proximity with the target, and an obstructed view may cause the hunter to miss a visual cue from the animal: a mother protecting her young, a rutting bull, etc. Another drawback is the weight of the quiver. An archer must elevate the bow with his or her arms during use, and added weight can fatigue the archer.
The weight of the quiver is also offset from the bow's center of gravity. Most bow-mounted quivers on the market today hold arrows on the right side of a right hand bow (left side of a left hand bow) as viewed by the archer shooting the bow. This placement causes the bow to balance off-center toward the dominant hand of the shooter (i.e., to the right for a right handed shooter). Therefore, the weight and position of the quiver affects the accuracy and precision of the bow. To remedy the issues associated with a bow-mounted quiver the archer may carry the quiver by hand, on a backpack, or on a belt as mentioned above. However, this would necessitate the use of a belt or backpack or result in fatigue of the archer if the archer carried the quiver by hand.
SUMMARY OF THE INVENTION
It is thus an aspect of embodiments of the invention to provide a stabilizer/quiver that functions as both a quiver and a stabilizer. It is another aspect of embodiments of the invention to provide a stabilizer/quiver that reduces the overall weight of the bow and improves the reliability of the bow. A separate stabilizer and quiver configuration weighs more than a combined stabilizer/quiver because two components have been reduced to one. Further, because there are fewer components, the stabilizer/quiver is less susceptible to failure. Thus, a combined stabilizer/quiver improves the reliability of the bow.
It is another aspect of embodiments of the invention to improve the effectiveness of the bow by improving its accuracy and precision. In some embodiments of the invention, the quiver is substantially aligned with the center of mass of the bow such that the quiver does not pull the bow to one side. The resulting balance of the bow relieves the archer from one source of inaccuracy and imprecision, which results in a more effective bow.
It is a further aspect of embodiments of the invention to provide a more compact bow. While target archers prefer longer stabilizers, hunters necessarily require more discrete stabilizers so they can move about varied terrain and stalk their target. The invention provides a more compact stabilizer, and thus a more compact bow, because the quiver and arrows of the invention contribute to the mass extending forward from the bow. Thus, the quiver and arrows contribute to the stabilizing function of the stabilizer/quiver, and embodiments of the invention need not be as long as they otherwise would be. The resulting bow provides additional mobility for a hunter who needs to traverse varied terrain.
It is another aspect of embodiments of the invention to improve the safety of the archer, specifically the hunter. As mentioned above, a vertically oriented quiver obstructs the view of the hunter, and the hunter may miss visual cues from the target, animals such as the target's mother, or the environment. A combined stabilizer/quiver is generally horizontally oriented, and thus, the hunter maintains a clear view of his target and the surrounding environment. This allows the hunter to properly anticipate and/or mitigate any potential threats, which improves the overall safety of the hunter.
It is a further aspect of embodiments of the invention to provide a stabilizer/quiver that may detach and quickly disassemble. The stabilizer/quiver of the invention may attach to the bow and may be secured by components that are tightened by hand and not necessarily by other means such as an Allen wrench or a screwdriver. A hand-operated means for securing the stabilizer/quiver allows the archer to detach and quickly disassemble the quiver for easier carrying or storage without the necessity of carrying, or remembering to carry, the proper tool.
It is another aspect of embodiment of the invention to provide a stabilizer/quiver that is rotatable relative to a bow. In some embodiments of the invention, the default position for the stabilizer/quiver is extending forward from the bow and generally parallel with the ground when the bow is in a firing position. Thus, the stabilizer/quiver contributes to the overall stability of the bow. However, in other instances it may be advantageous to adjust the position of the stabilizer/quiver for easy storage, to adjust the stabilizing function, etc. In some embodiments, a bow attachment is used to interconnect the stabilizer/quiver to a portion of the bow such as the riser. The bow attachment may comprise two or more components disposed about an axis such that the stabilizer/quiver rotates relative to the bow. Further, the bow attachment may comprise a bolt, screw, or other similar device that is configured to lock the position of the stabilizer/quiver relative to the bow once the position of the stabilizer/quiver has been adjusted. The stabilizer/quiver may rotate about the rotatable bow attachment such that the stabilizer/quiver may rotate parallel with the riser of the bow similar to traditional bow-mounted quiver, or the stabilizer/quiver may be incrementally rotated to adjust the stabilizing effect of the stabilizer/quiver, access to the arrows, etc.
It is another aspect of embodiments of the invention to provide a stabilizer/quiver that comprises fully adjustable components. In some embodiments, the stabilizer/quiver comprises a shaft, a broadhead hood and an arrow gripper that secure arrows, and a bow attachment that interconnects the stabilizer/quiver to the bow. The broadhead hood, the arrow gripper, and the bow attachment may be disposed about the shaft in any order and in any position along the shaft. For example, these components may be arranged such that the shaft extends forward like a stabilizer, but the arrows are disposed rearward of the riser of the bow. In other embodiments, both the shaft and the arrows may be disposed forward of the riser of the bow or both disposed rearward of the riser.
It is another aspect of embodiments of the invention to provide a quiver/stabilizer that comprises an adjustable shaft. The shaft may comprise one or more hinged sections such that the position of the hinged sections and the relative angle between hinged sections is adjustable. In another example, the shaft is telescoping in nature. Therefore, an archer may fully extend the shaft to provide the greatest stabilizing effect, and the archer may collapse the shaft to any shorter length to provide more maneuverability or easier storage.
It is another aspect of the invention to provide a stabilizer/quiver that has an adjustable length in response to the number of arrows the stabilizer/quiver carries. In some embodiments of the invention, the stabilizer/quiver carries arrows and the stabilizer/quiver functions as a stabilizer. As a user selects arrows from the stabilizer/quiver and fires the arrows, the weight of the stabilizer/quiver changes, and the stabilizing properties of the stabilizer/quiver may also change. Thus, in some embodiments, the shaft of the stabilizer/quiver extends further out as each arrow is selected to compensate for the reduced weight of the stabilizer/quiver. This movement may be induced manually, for example, by a mechanical system such as a ratchet and pawl or automatically, for example, by an electrical system such as an electrical linear motor. Now the stabilizer/quiver may have consistent stabilizing properties, even as arrows are selected and fired.
It is another aspect of various embodiments of the invention to provide a stabilizer/quiver that is fully compatible with bow attachments and configurations. For example, modern bows often comprise platforms and components to attach aftermarket parts such as optics and sights. Embodiments of the invention may comprise a bow attachment that is adapted to interconnect to any other feature commonly incorporated in bows.
It is another aspect of embodiments of the invention to provide a broadhead hood that covers the broadheads of an arrow for safety purposes. In some embodiments, the broadhead hood comprises a housing with a broadhead hood insert, and a user may insert the broadhead of an arrow into the broadhead hood insert. Next, the user may engage an adjustable feature that compresses a portion of the broadhead hood insert such that the broadhead hood insert grips or locks the broadheads snuggly in the broadhead hood. The ability to grip or lock the broadheads reduces vibrations in the overall bow configuration and it also aids the archer by preventing arrows from falling out of the broadhead hood as the archer negotiates varied terrain. When the archer has established a position and needs access to the arrows, the archer may simply engage the adjustable feature to relieve the compression within the broadhead hood insert.
It is another aspect of embodiment of the invention to provide a stabilizer/quiver that selectively interconnects to an existing stabilizer. Many bows in circulation already comprise a stabilizer. Therefore, some embodiments of the invention may comprise features such as a broadhead hood and an arrow gripper that attach to the preexisting stabilizer to form a stabilizer/quiver. The arrow gripper and the broadhead hood may comprise adjustable means such that the arrow gripper and the broadhead hood may compress about the outer surface of the stabilizer. In other embodiments, the arrow gripper and broadhead hood snap onto the existing stabilizer. It will be appreciated that a variety of means to attach components to an existing stabilizer are discussed elsewhere herein and known in the art.
One particular embodiment of the invention is a combined stabilizer/quiver for a bow, comprising a shaft having a proximate end, a distal end, and an outer surface; a bow attachment feature located near the proximate end of the shaft, the bow attachment feature is adapted to secure the shaft to a bow; a broadhead hood disposed about the outer surface of the shaft, the broadhead hood comprising at least one recess configured to receive a first portion of an arrow; and an arrow gripper disposed about the outer surface of the shaft, the arrow gripper comprising at least one slot configured to receive a second portion of the arrow.
Another embodiment of the invention is a system for stabilizing a bow and storing arrows, comprising a bow having a riser, and an arrow having an arrowhead and a body; a shaft extending from the riser of the bow, the shaft having a proximate end, a distal end, and an outer surface; a broadhead hood disposed about the outer surface of the shaft, the broadhead hood comprising at least one recess, wherein the arrowhead of the arrow is positioned in the at least one slot; and an arrow gripper disposed about the outer surface of the shaft, the arrow gripper comprising at least one slot, wherein the body of the arrow is positioned in the at least one slot.
Yet another embodiment of the invention is a combined stabilizer/quiver for stabilizing a bow and storing arrows, comprising a shaft having a proximate end, a distal end, and an outer surface; a bow attachment feature located near the proximate end of the shaft, the bow attachment feature is adapted to secure the shaft to a bow; a broadhead hood disposed near the distal end of the shaft and about the outer surface of the shaft, the broadhead hood comprising a housing at least partially defining a volume; and a broadhead hood insert disposed in the volume and comprising at least one recess, the broadhead hood insert is compressible between a first volume and a second volume; a tension lever operably interconnected to the broadhead hood insert, the tension lever is moveable between a first position and a second position to compress the broadhead hood insert between the first volume and the second volume; and an arrow gripper disposed between the bow attachment feature and the broadhead, the arrow gripper disposed about the outer surface of the shaft, the arrow gripper comprising at least one slot configured to receive a body of the arrow.
These and other advantages will be apparent from the disclosure of the invention(s) contained herein. The above-described embodiments, objectives, and configurations are neither complete nor exhaustive. The Summary of the Invention is neither intended nor should it be construed as being representative of the full extent and scope of the invention. Moreover, references made herein to “the invention” or aspects thereof should be understood to mean certain embodiments of the invention and should not necessarily be construed as limiting all embodiments to a particular description. The invention is set forth in various levels of detail in the Summary of the Invention as well as in the attached drawings and Detailed Description and no limitation as to the scope of the invention is intended by either the inclusion or non-inclusion of elements, components, etc. in this Summary of the Invention. Additional aspects of the invention will become more readily apparent from the Detailed Description particularly when taken together with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the disclosure and together with the general description of the disclosure given above and the detailed description of the drawings given below, serve to explain the principles of the disclosures.
FIG. 1 is a side elevation view of a typical compound bow according to one embodiment of the invention;
FIG. 2 is an exploded perspective view of a combined stabilizer/quiver according to one embodiment of the invention;
FIG. 3 is a perspective view of an assembled stabilizer/quiver according to one embodiment of the invention wherein arrows are disposed within the stabilizer/quiver;
FIG. 4 is a side elevation view of a stabilizer/quiver according to one embodiment of the invention wherein the stabilizer/quiver is attached to a riser of a bow;
FIG. 5 is a side elevation view of a stabilizer/quiver according to one embodiment of the invention showing a vertical angle between the stabilizer/quiver and a riser;
FIG. 6 is a perspective view of a stabilizer/quiver according to one embodiment of the invention showing a horizontal angle between the stabilizer/quiver and a riser;
FIG. 7 is a perspective view of a broadhead hood according to one embodiment of the invention wherein a tension lever is open; and
FIG. 8 is a perspective view of a broadhead hood according to one embodiment of the invention wherein a tension level is closed.
To assist in the understanding of the embodiments of the invention the following list of components and associated numbering found in the drawings is provided herein:
Component No.
Component
2
Bow
4
Riser
6
Upper Limb
8
Upper Bolt
10
Lower Limb
12
Lower Bolt
14
Upper Cam
16
Lower Cam
18
Bow String
20
Nocking Point
22
Cable Guard
24
Bow Sight
26
Arrow Rest
28
Grip
30
Stabilizer
32
Stabilizer/Quiver
34
Shaft
36
Arrow Gripper Bracket
38
First Portion
40
Second Portion
42
Arrow Gripper
44
Lockdown Bolt
46
Bow Attachment
48
Quick Detach Knob
50
Broadhead Hood
52
Broadhead Hood Insert
54
Arrow
56
Vertical Angle
58
Horizontal Angle
60
Tension Plate
62
Tension Lever
It should be understood that the drawings are not necessarily to scale, and various dimensions may be altered. In certain instances, details that are not necessary for an understanding of the invention or that render other details difficult to perceive may have been omitted. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein.
DETAILED DESCRIPTION
The invention has significant benefits across a broad spectrum of endeavors. It is the Applicant's intent that this specification and the claims appended hereto be accorded a breadth in keeping with the scope and spirit of the invention being disclosed despite what might appear to be limiting language imposed by the requirements of referring to the specific examples disclosed. To acquaint persons skilled in the pertinent arts most closely related to the invention, an embodiment that illustrates the best mode now contemplated for putting the invention into practice is described herein by, and with reference to, the annexed drawings that form a part of the specification. The exemplary embodiment is described in detail without attempting to describe all of the various forms and modifications in which the invention might be embodied. As such, the embodiments described herein are illustrative, and as will become apparent to those skilled in the arts, may be modified in numerous ways within the scope and spirit of the invention.
Although the following text sets forth a detailed description of numerous different embodiments, it should be understood that the detailed description is to be construed as exemplary only and does not describe every possible embodiment since describing every possible embodiment would be impractical, if not impossible. Numerous alternative embodiments could be implemented, using either current technology or technology developed after the filing date of this patent, which would still fall within the scope of the claims. To the extent that any term recited in the claims at the end of this patent is referred to in this patent in a manner consistent with a single meaning, that is done for sake of clarity only so as to not confuse the reader, and it is not intended that such claim term by limited, by implication or otherwise, to that single meaning.
Various embodiments of the invention are described herein and as depicted in the drawings. It is expressly understood that although the figures depict bows with quiver and stabilizer combinations, the invention is not limited to these embodiments. It should be further understood that the terms “arrow gripper bracket” and “bracket”, and “arrow gripper” and “gripper” may be used interchangeably, respectively.
Now referring to FIG. 1 , a typical compound bow 2 is provided. The central portion is a riser 4 , which is a central, rigid portion of the bow 2 . The riser 4 is where a user grips the bow 2 , and the riser 4 provides a central location to dispose other portions of the bow 2 and various accessories. Extending upward from the riser 4 is an upper limb 6 which is affixed to the riser 4 . In this embodiment, an upper bolt 8 is used to affix the upper limb 6 to the riser 4 . In other embodiments, the upper bolt 8 or another fastening means may be used to adjust the interconnection between the upper limb 6 and the riser 4 to provide different performance characteristics to the bow 2 . Similarly, a lower limb 10 extends downward from the riser 4 , and a lower bolt 12 affixes the lower limb 10 to the riser 4 .
Each of the upper limb 6 and the lower limb 10 have a proximate end, which is affixed to the riser 4 , and a distal end. An upper cam 14 is disposed on the distal end of the upper limb 6 , and a lower cam 16 is disposed on the distal end of the lower limb 10 . A bow string 18 is operatively interconnected to each the upper cam 14 and the lower cam 16 . Cams may come in a variety of forms including, but not limited to, single cams, hybrid cams, dual cams, binary cams, quad cams, and hinged cams. As a user engages the bow 2 and pulls on the bow string 18 , the upper cam 14 and the lower cam 16 rotate as the limbs 6 , 10 begin to flex. When the cams 14 , 16 completely rotate, the draw weight of the bow string 18 lets off, or in other words, the draw weight decreases from the peak draw weight. This allows an archer to maintain a drawn bow string 18 with less effort. The “let off” may be expressed in term of a percentage of the peak draw weight of the bow string 18 . Let off is typically between 60-85% of the peak draw weight of the bow string 18 . This means that a bow 2 may let off 60% of the peak draw weight of the bow string 18 , and the user needs to maintain only 40% of the peak draw weight to keep the bow string 18 drawn. Other bows may have let off between 50-99% of the peak draw weight.
FIG. 1 also illustrates other features typically found on a bow 2 . A nocking point 20 is disposed on the bow string 18 approximately halfway between the cams 14 , 16 . The nocking point 20 is near where the user locates an arrow on the bow string 18 . A cable guard 22 extends rearward from the riser 4 and past the bow string 18 . The cable guard 22 segregates additional portions of the bow string 18 from the portion of the bow string 18 that comprises the nocking point 20 such that the additional portions do not interfere with the arrow. A bow sight 24 is disposed on the riser 4 and aids the user in visualizing where a fired arrow will travel. The riser 4 also comprises an arrow rest 26 , which is where the shaft of a projectile rests as a user engages the bow 2 . Finally, the riser 4 comprises a grip 28 , which is the portion of the riser 4 that the user grips with his or her off hand.
Also depicted in FIG. 1 is a stabilizer 30 . The stabilizer 30 in this embodiment of the invention is affixed to the riser 4 of the bow 2 , and the stabilizer 30 extends forward from the bow 2 . The bow 2 may comprise a threaded female recess disposed on the forward end of the bow 2 , and the stabilizer 30 may comprise a threaded male insert such that an archer may screw the stabilizer 30 into the bow 2 . Embodiments of the invention may comprise similar attachment means and other attachments means discussed herein. As mentioned elsewhere herein, the general purpose of the stabilizer 30 is to provide balance to the bow 2 , to dampen vibrations as an arrow is fired, and to aid a user in holding a drawn bow 2 steady.
Now referring to FIG. 2 , an embodiment of a combined stabilizer/quiver 32 for a bow is provided. A shaft 34 provides length to the stabilizer/quiver 32 , and in this embodiment, the shaft 34 is cylindrically shaped having a proximal end and a distal end. An arrow gripper bracket 36 may be disposed about the shaft 34 towards the proximate end of the shaft 34 . A first portion 38 of the arrow gripper bracket 36 may be disposed around the shaft 34 , and the first portion 34 is cylindrically shaped but comprises a longitudinally disposed gap. A lockdown bolt 44 may be used to secure the arrow gripper bracket 36 to the shaft 34 . As a user engages the lockdown bolt 44 , the longitudinally disposed gap of the first portion 34 closes, and the first portion 34 of the arrow gripper bracket 36 compresses onto the outer surface of the shaft 34 of the stabilizer/quiver 32 .
The arrow gripper bracket 36 shown in FIG. 2 also comprises a second portion 36 that extends outward, radially from the shaft 34 of the stabilizer/quiver 32 . The second portion 36 comprises a recess and two ridges. An arrow gripper 42 comprises two grooves which correspond to the two ridges of the second portion 40 . This allows the arrow gripper 42 to longitudinally slide into the second portion 40 of the arrow gripper bracket 36 . The lockdown bolt 44 may secure the first portion 38 to the shaft 34 , and the lockdown bolt 44 may also continue through the first portion 38 , through the second portion 40 , and into the arrow gripper 42 in order to secure the arrow gripper 42 to the second portion 40 . It will be appreciated that there may be other embodiments of the invention where the arrow gripper 42 snaps into the second portion 40 or is secured on the second portion 40 with other attachment means. In yet further embodiments, the arrow gripper 42 is screwed onto the second portion 40 , is welded to the second portion 40 , or is a single continuous structure with the second portion 40 . The arrow gripper 42 may interface with the second portion 40 via any means commonly known in the art.
The arrow gripper 42 comprises at least one slot or aperture devoted to securing the body or shaft of an arrow. This slot comprises a portion that is approximately the same diameter as the arrow's body or shaft, but the slot also comprises an entry portion that is smaller than the diameter of the arrow's body or shaft. This configuration allows an arrow to snap into place in the arrow gripper 42 , which secures the arrow by virtue of the entry portion that has a diameter smaller than the arrow's body or shaft.
Next, a bow attachment 46 is disposed around the shaft 34 of the stabilizer/quiver 32 towards the proximate end of the stabilizer/quiver 32 . The bow attachment 46 is similar to the first portion 38 of the arrow gripper bracket 36 . The bow attachment 46 is cylindrically shaped with a longitudinal gap. A quick detach knob 48 is used to secure the bow attachment 46 to the shaft 34 of the stabilizer/quiver 32 and to a portion of the riser 4 of the bow 2 . As a user engages the quick detach knob 48 , the longitudinal gap closes and the bow attachment 46 compresses onto the outer surface of the shaft 34 of the stabilizer/quiver 32 . The bow attachment 46 may also be screwed, welded, formed continuously with, snapped, and and/or secured to the shaft 34 via any other means of interconnection discussed herein or commonly known in the art.
FIG. 2 shows a broadhead hood 50 disposed on the distal end of the shaft 34 of the stabilizer/quiver 32 . The broadhead hood 50 may be secured by means of a compression or interference fit. In other embodiments, the broadhead hood 50 may be secured by the lockdown bolt or the quick detach knob used by the arrow gripper bracket 36 and the bow attachment 42 , respectively.
The broadhead hood 50 comprises a housing with a recess configured to receive a broadhead hood insert 52 . The tips of arrows are typically fitted with a broadhead for hunting purposes, and broadheads generally comprise at least one sharpened edge, which can present a danger to the user if the sharpened edge is exposed. Thus, the broadheads may be disposed and secured in the broadhead hood insert 52 . The broadhead hood insert 52 may comprise a material that is punctured by the broadhead of an arrow, then the material compresses around the broadhead. In other embodiments, the material is cut out into a shape that receives and secures a broadhead. The material may be foam rubber, rubber, polyethylene, or other material commonly used in the art, and the broadhead hood insert 52 may comprise an adjustable feature such as a screw that allows an archer to compress the rubber around the broadhead. In yet further embodiments, the broadhead hood insert 52 may comprise locking features that snap into a notch or other geometrical feature of the broadhead. In this embodiment, the number of locking features may be greater than, less than, or equal to the number of slots in the arrow gripper 42 .
Another feature of the stabilizer/quiver 32 is the ability to dampen vibrations caused by operation of the bow 2 . The shaft 34 itself may be adjustable in length and/or shape. A shaft 34 configured in different shapes and disposed in different locations will provide different moment forces about the center of the bow's 2 mass, and thus different dampening and stabilizing properties. In addition, the shaft 34 will provide different mode shapes and frequencies. The shape of the shaft 34 may be manipulated with multiple segments, and the shaft 34 may be a shape other than a cylinder. For example, a square shaft, a shaft with a plurality of ribs, and/or a shaft with a plurality of apertures may provide optimum dampening qualities. Further, the shaft 34 may be encased in or cored with rubber, vibration foam, or any other material that enhances the vibration dampening properties of the combined stabilizer/quiver 32 .
An archer may adjust the shaft 34 until the desired dampening shape is achieved. In some embodiments of the invention, the shaft 34 comprises a hollow, enclosed volume which may be filled with a liquid. A shaft 34 with a liquid core may also provide enhanced dampening properties. Further, different segments of a segmented shaft 34 may be filled with various liquids, and other segments of the segmented shaft 34 may remain solid or hollow. In a single shaft 34 design, the interior of the shaft 34 may comprise a plurality of compartments which may be filled with a liquid. Further, the sides of the shaft 34 may be clear such that an archer may discern the amount of liquid in each compartment. Liquids may be water, and liquids may be less or more dense than water such as oil and mercury.
Other embodiments of the invention may employ other means to effectuate the dampening properties of the stabilizer/quiver 32 . The shaft may comprise a piston with an electronic timing system such that the piston is displaced as an archer fires an arrow. In this embodiment a sensor may be disposed on the limbs 6 , 10 such that the sensor discerns when the bow is drawn, then when the bow string 18 is release. The sensor may be in electronic communication with the stabilizer/quiver 32 and the piston system. When the sensor detects the bow string 18 release, the piston may adjust its position within the shaft 34 of the stabilizer/quiver 32 to counteract the flexing of the limbs 6 , 10 , and the propulsion of the projectile. In other embodiments, a spring system or hydraulic system may be employed within the shaft 34 . It will be appreciated that commonly known dampening devices may be passively or actively used in the shaft 34 of the stabilizer/quiver 32 to improve the dampening and stabilizing properties of the stabilizer/quiver 32 .
Now referring to FIG. 3 , a stabilizer/quiver 32 is provided where arrows 54 are disposed in the stabilizer/quiver 32 . The bodies or shafts of the arrows 54 are disposed in the slots of the arrow gripper bracket 36 , and the broadhead of the arrow is disposed in the broadhead hood insert 52 . Also shown in FIG. 3 is the proximate end of the bow attachment 46 , which may be screwed into a portion of the riser 4 of the bow 2 . In other embodiments, the bow attachment 46 may compress about a portion of the riser 4 similar to how the bow attachment 46 may compress around the outer surface of the shaft 34 of the stabilizer/quiver 32 .
The broadhead hood 50 , the arrow gripper bracket 36 , and the bow attachment 46 are all adjustable along the length of the shaft 34 of the stabilizer/quiver 32 . In one embodiment, the broadhead hood 50 remains disposed on the distal end of the shaft 34 , and the arrow gripper bracket 36 and the bow attachment 46 are moveable towards the distal end of the shaft 34 and are adjustable as far as the broadhead hood 50 . In this configuration, the shaft 34 and the arrows 54 are moved rearward relative to the riser 4 of the bow 2 . In another embodiment, the broadhead hood 50 is movable towards the proximate end of the shaft 34 and is adjustable as far as the arrow gripper bracket 36 and/or the bow attachment 54 . In this configuration, the shaft 34 remains extended forward as a traditional stabilizer, but the arrows 54 are disposed substantially rearward of the riser 4 of the bow 2 . In yet another embodiment, the arrow gripper bracket 36 is disposed on the proximate end of the shaft 34 , the broadhead hood 50 is disposed on the distal end of the shaft 34 , and the bow attachment 46 is disposed on the shaft 34 therebetween. The bow attachment 46 may then be adjusted or moved along the length of the shaft 34 . In this configuration, the shaft 34 and the arrows 54 move forward or rearward of the riser 4 of the bow 2 .
Now referring to FIG. 4 , a stabilizer/quiver 32 attached to a bow 2 is provided. The bow attachment 46 is secured to the riser 4 of the bow 2 , and the arrows 54 are disposed to one side of the riser 4 . In some embodiments, the bow attachment 46 may be secured to the front side of the riser 4 , and in other embodiments, the bow attachment 46 may be secured to the sides or the back of the riser 4 . Further, the arrows 54 may be arrayed on one side of the riser 4 , on both sides of the riser 4 , or through the riser 4 .
The arrow gripper 42 and the arrow gripper bracket 36 may attach to the shaft 34 of the stabilizer/quiver 32 in some embodiments of the invention, but in other embodiments the shafts of the arrows may be secured onto features of the riser 4 or the limbs 6 , 10 or any other component discussed herein.
In some embodiments, the stabilizer/quiver 32 is between 1 inch and 55 inches in length. In various embodiments, the stabilizer/quiver 32 is 12 inches to 50 inches in length. In some embodiments, the stabilizer/quiver 32 is 4 inches to 12 inches in length.
Now referring to FIGS. 5 and 6 , the stabilizer 30 is adjustable at various angles relative to the bow 2 , specifically the riser 4 of the bow 2 . It should be understood that while the stabilizer 30 is used for exemplary purposes, the same adjustability concepts apply to the stabilizer/quiver 32 in accordance with embodiments described elsewhere herein.
FIG. 5 shows that the stabilizer 30 may be adjustable in a plane through the vertical axis of the riser 4 and the longitudinal axis of the stabilizer 30 . A vertical angle 56 may be measured from a substantially horizontal plane. In the embodiment shown in FIG. 5 , the stabilizer is adjustable between 90 and −90 degrees from the horizontal plane. In other embodiments, the stabilizer 30 is fully adjustable about an axis, which means that the stabilizer 30 may rotate a full 360 degrees. The stabilizer 30 may be secured in various positions using a thumbscrew to, for example, impinge on a ball portion of a ball-and-socket joint to secure the stabilizer 30 in place. In other embodiments, the stabilizer 30 may be secured in various positions using an interference fit. For example, a protrusion on one component such as the stabilizer 30 may correspond to a depression in another component such as the riser 4 . When the protrusion and depression are aligned, there is no interference, but when the protrusion and depression fall out of alignment, the protrusion interferes with the non-depression portion of the riser 4 . Thus, this interference maintains the orientation of the stabilizer 30 relative to the riser 4 . A user may press the protrusion through the interference such that the protrusion is aligned with a second depression, and the stabilizer 30 is maintained in a second position relative to the riser 4 . A level such as a bubble level may be integrated into the stabilizer 30 to help a user such as a hunter orient the stabilizer 30 relative to the ground.
FIG. 6 shows a perspective view of a bow 2 comprising a stabilizer 30 wherein the stabilizer is adjustable in a horizontal plane through the longitudinal axis of the stabilizer 30 and substantially parallel to the ground when the bow 2 is in a firing position. A horizontal angle 58 is measured between the stabilizer 30 and a vertical plane through the vertical axis of the riser 4 and the longitudinal axis of the stabilizer 30 or a vertical plane through the vertical axis of the riser 4 and the string. In the embodiment depicted in FIG. 6 , the horizontal angle 58 may extend between 45 and −45 degrees. In other embodiments, the stabilizer 30 may be rotatable such that the stabilizer 30 extends rearward of the riser 4 . In other words, the horizontal angle 58 may extends between 180 and −180 degrees. In some embodiments, the adjustable orientation of the stabilizer 30 may be achieved with one or more rotatable axes disposed in the bow attachment 46 , a ball and socket joint, or any other joint commonly used to manipulate the position of an object.
Now referring to FIG. 7 , a detailed view of a broadhead hood 50 is provided. In this embodiment, the broadhead hood 50 comprises a housing where a broadhead hood insert 52 may be disposed. In this particular embodiment, the broadhead hood insert 52 is a foam rubber insert with recesses that receive broadheads or other arrowheads, but other embodiments may be comprised of other materials that deform in response to a force such as a physical or electromagnetic force. Some materials may have a volume fraction that characterizes the volume percentage of a particular material or void. For example, a low density foamed rubber may have a void fraction between approximately 35% and 80%. In some embodiments, the broadhead hood insert 52 is a material that has a void fraction between approximately 10% and 90%. In various embodiments, the broadhead hood insert 52 is a material that has a void fraction between approximately 35% and 80%. In some embodiments, the broadhead hood insert 52 is a material that has a void fraction of approximately 40%.
Adjacent to the broadhead hood insert 52 is a tension plate 60 , which is disposed along the majority of one surface of the broadhead hood insert 52 .
Disposed on the outer surface of the broadhead hood 50 is a tension lever 62 , which pivots about a pin or axis. The tension lever 62 comprises two ends: a handle end that extends outwardly from the broadhead hood 50 and a lever end that is operably interconnected to the tension plate 60 . In some embodiments, the handle end extends further from the pin or axis than the lever end. The tension lever 62 depicted in FIG. 7 is in an open position, meaning that the tension lever 62 , specifically the lever end, is not imparting any force on the tension plate 60 .
Now referring to FIG. 8 , the tension lever 62 of the embodiment shown in FIG. 7 is in a closed position. Now the tension lever 62 has pivoted about the pin or axis, the handle end of the tension lever 62 extends alongside the broadhead hood 50 , and the lever end of the tension lever 62 has pivoted into the tension plate 60 . The physical force from the tension lever 62 causes the tension plate 60 to press into the broadhead hood insert 52 , which causes the broadhead hood insert 52 to deform and press into the broadheads or other arrowheads that are disposed within the broadhead hood insert 52 . In the embodiment depicted in FIGS. 7 and 8 , the four cutouts for the broadheads are arranged in a staggered fashion. Other embodiments may have a different number of cutouts, different arrangement of cutouts, etc. Further, in the embodiments depicted in FIGS. 7 and 8 , the tension plate 60 is disposed along one side of the broadhead hood insert 52 such that the tension plate 60 presses against the flat side of the broadheads. In other embodiments, the tension plate 60 may be disposed along another surface or surfaces such that engagement of the tension lever 62 causes the tension plate 60 to press against the broadheads at a different angle.
The invention has significant benefits across a broad spectrum of endeavors. It is the Applicant's intent that this specification and the claims appended hereto be accorded a breadth in keeping with the scope and spirit of the invention being disclosed despite what might appear to be limiting language imposed by the requirements of referring to the specific examples disclosed.
The phrases “at least one”, “one or more”, and “and/or”, as used herein, are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B, and C”, “at least one of A, B, or C”, “one or more of A, B, and C”, “one or more of A, B, or C,” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B, and C together.
Unless otherwise indicated, all numbers expressing quantities, dimensions, conditions, and so forth used in the specification, drawings, and claims are to be understood as being modified in all instances by the term “about.”
The term “a” or “an” entity, as used herein, refers to one or more of that entity. As such, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein.
The use of “including,” “comprising,” or “having,” and variations thereof, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Accordingly, the terms “including,” “comprising,” or “having” and variations thereof can be used interchangeably herein.
It shall be understood that the term “means” as used herein shall be given its broadest possible interpretation in accordance with 35 U.S.C., Section 112(f). Accordingly, a claim incorporating the term “means” shall cover all structures, materials, or acts set forth herein, and all of the equivalents thereof. Further, the structures, materials, or acts, and the equivalents thereof, shall include all those described in the summary of the invention, brief description of the drawings, detailed description, abstract, and claims themselves.
The foregoing description of the invention has been presented for illustration and description purposes. However, the description is not intended to limit the invention to only the forms disclosed herein. In the foregoing Detailed Description for example, various features of the invention are grouped together in one or more embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are hereby incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of the invention.
Consequently, variations and modifications commensurate with the above teachings and skill and knowledge of the relevant art are within the scope of the invention. The embodiments described herein above are further intended to explain best modes of practicing the invention and to enable others skilled in the art to utilize the invention in such a manner, or include other embodiments with various modifications as required by the particular application(s) or use(s) of the invention. Thus, it is intended that the claims be construed to include alternative embodiments to the extent permitted by the prior art.
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A combined stabilizer/quiver for a bow is provided that may store arrows and may also function as a stabilizer. The combined stabilizer/quiver may comprise a shaft that extends forward from the front side of a bow and functions as a stabilizer, and arrows may be disposed substantially parallel to the shaft and contribute to the stabilizing function. With two components combined into one, the bow has less weight, improved accuracy and precision, and greater versatility. Alternatively, a quiver is provided which is adapted to attach to a conventional stabilizer which is attached to a riser of a bow.
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INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS
[0001] Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 CFR 1 . 57 .
BACKGROUND
[0002] 1. Field
[0003] The present disclose relates to a dispensing pump, and more particularly, to a dispensing pump that may be used in a process of manufacturing an electronic product and may dispense an accurate amount of a liquid, such as a liquid synthetic resin, at high speed.
[0004] 2. Discussion of Related Technology
[0005] Pumps for dispensing liquid are used in various technical fields, such as processes of manufacturing electronic products by using semiconductor chips, and the like.
[0006] In particular, dispensing pumps are widely used in an underfill process of a semiconductor process. The underfill process is usually used in a surface mounting technique, such as a flip chip in which a plurality of metal balls are formed on a surface facing a substrate and which electrically connects the substrate and a semiconductor chip via the plurality of metal balls. If a liquid synthetic resin is applied onto a circumference of the semiconductor chip, the resin is dispersed into a space between the semiconductor chip and the substrate by a capillary phenomenon and is filled in a space between the metal balls. The resin that fills the space between the semiconductor chip and the substrate is hardened so that adhesive strength between the semiconductor chip and the substrate can be improved. In addition, the hardened resin serves as a shock absorber and dissipates heat generated in the semiconductor chip.
[0007] A function of dispensing a liquid at high speed of such dispensing pumps becomes significant. Korean Patent Laid-open Publication Nos. 10-2005-0093935 and 10-2010-0045678 disclose a structure of a pump for dispensing a resin by ascending/descending a valve due to interaction between a cam and a cam follower. Such dispensing pumps according to the related art have excellent performance but have a limitation in speed at which a valve rod descends due to a structure of cam protrusions of a cam member and a structure of a roller. Thus, there are some difficulties in dispensing the liquid at high speed, and in particular, it is difficult to dispense a liquid with high viscosity at high speed.
SUMMARY
[0008] One aspect of the present invention provides a valve accelerating type dispensing pump that may descend a valve rod at high speed and thus may dispense a liquid with high viscosity at high speed.
[0009] Another aspect of the present invention provides a valve accelerating type dispensing pump including: a pump body; a valve body including an inlet path on which a liquid from an outside is supplied, a reservoir in which the liquid supplied via the inlet path is stored, and a discharge path on which the liquid stored in the reservoir is discharged, the valve body being installed at the pump body; a valve rod pressurizing the liquid stored in the reservoir of the valve body and inserted in the reservoir of the valve body so that the liquid is discharged via the discharge path; an operating rod connected to the valve rod and allowing the valve rod to move relative to the valve body; a cam member including a through hole through which the operating rod passes and cam protrusions formed along a circumferential direction of the cam member based on the through hole and having inclined surfaces formed so that a height of the cam protrusions increases, the cam member being installed at the pump body so that the cam member rotates around the through hole; a rotating unit rotating the cam member; a cam follower including rollers that roll on the inclined surfaces of the cam protrusions when the cam member rotates, the cam follower coupled to the operating rod and allowing the valve rod to move relative to the valve body; an accelerating member assembled with the cam follower to allow relative rotation of the cam follower within a predetermined angle range and installed at the pump body so as to make a linear motion approaching the cam member; and an elastic member installed between the pump body and the accelerating member and providing an elastic force to the accelerating member so that the accelerating member approaches the cam member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The above and other features and advantages of the present invention will become more apparent by describing in detail embodiments thereof with reference to the attached drawings in which:
[0011] FIG. 1 is a perspective view of a valve accelerating type dispensing pump according to an embodiment of the present invention;
[0012] FIG. 2 is an exploded perspective view of main elements of the valve accelerating type dispensing pump illustrated in FIG. 1 ;
[0013] FIG. 3 is a cross-sectional view taken along a line of the valve accelerating type dispensing pump of FIG. 1 ;
[0014] FIG. 4 is a cross-sectional view taken along a line IV-IV of the valve accelerating type dispensing pump of FIG. 1 ;
[0015] FIGS. 5A , 5 B, 6 A, 6 B, 7 A, and 7 B are schematic views for explaining an operation of the valve accelerating type dispensing pump of FIG. 1 ; and
[0016] FIG. 8 is an exploded perspective view of main elements of a valve accelerating type dispensing pump according to another embodiment of the present invention.
DETAILED DESCRIPTION OF EMBODIMENTS
[0017] Embodiments of the present invention will now be described more fully with reference to the accompanying drawings in which embodiments of the invention are shown.
[0018] FIG. 1 is a perspective view of a valve accelerating type dispensing pump according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of main elements of the valve accelerating type dispensing pump illustrated in FIG. 1 , and FIG. 3 is a cross-sectional view taken along a line of the valve accelerating type dispensing pump of FIG. 1 .
[0019] Referring to FIGS. 1 through 3 , the valve accelerating type dispensing pump according to the present embodiment includes a pump body 100 , a valve body 110 , a valve rod 210 , an operating rod 220 , a cam member 300 , and a cam follower 400 .
[0020] The pump body 100 serves as a housing that supports the entire structure of the valve accelerating type dispensing pump. The pump body 100 is installed at a transfer device and is moved by the transfer device to allow a liquid to be dispensed.
[0021] The valve body 110 is installed at the pump body 100 . The valve body 110 includes an inlet path 111 , a reservoir 112 , and a discharge path 113 . The liquid stored in an external syringe (not shown) flows to the reservoir 112 via the inlet path 111 . The liquid stored in the reservoir 112 is discharged via the discharge path 113 due to an operation of the valve rod 210 that ascends/descends with respect to the reservoir 112 . A nozzle 120 is connected to the discharge path 113 so as to adjust dispensing characteristics of the liquid.
[0022] The valve rod 210 is inserted in the reservoir 112 and pressurizes the liquid stored in the reservoir 112 so as to discharge the liquid via the discharge path 113 .
[0023] The cam member 300 is disposed above the valve body 110 and the valve rod 210 and is installed at the pump body 100 . The cam member 300 is installed at the pump body 100 so as to rotate around a virtual central axis that extends in a lengthwise direction of the valve rod 210 . A bearing 130 is installed between the cam member 300 and the pump body 100 so that the cam member 300 may rotate with respect to the pump body 100 .
[0024] The cam member 300 rotates by a rotating unit 900 . The rotating unit 900 includes a motor 910 , a driving pulley 920 , a timing belt 930 , and a driven pulley 940 . The motor 910 is installed at the pump body 100 , and the driven pulley 940 is installed at the cam member 300 . The timing belt 930 connects the driving pulley 920 and the driven pulley 940 . If the motor 910 allows the driving pulley 920 to rotate, the driven pulley 940 rotates due to the timing belt 930 . As a result, the cam member 300 rotates.
[0025] The cam member 300 includes a through hole 320 and a plurality of cam protrusions 310 . The through hole 320 is formed to penetrate the center of the disc-shaped cam member 300 in a vertical direction. The plurality of cam protrusions 310 are arranged in a circumferential direction of the cam member 300 so that eight cam protrusions 310 are at the same angle intervals (i.e., at intervals of 45 degrees). The cam protrusions 310 are inclined in the same rotation direction along the circumferential direction of the cam member 300 . That is, the cam protrusions 310 include inclined surfaces 311 that are inclined so that the height of the cam protrusions 310 may increase gradually clockwise, as illustrated in FIG. 2 . Cross-sections of the cam protrusions 310 may be formed so that the inclined surfaces 311 are steeply bent from their tops to lower portions. In the present embodiment, the inclined surfaces 311 of the cam protrusions 310 are formed to be bent from their tops in the vertical direction, as illustrated in FIGS. 2 , 5 A, and 5 B.
[0026] The operating rod 220 is disposed in the through hole 320 of the cam member 300 and is coupled to the valve rod 210 . The operating rod 220 is coupled to the cam follower 400 and ascends or descends and allows the valve rod 210 to be moved up and down relative to the valve body 110 .
[0027] The cam follower 400 faces a surface on which the cam protrusions 310 of the cam member 300 are formed and ascends/descends with respect to the cam member 300 due to interaction between the cam protrusions 310 and the cam follower 400 . The cam follower 400 includes two rollers 420 that roll on the inclined surfaces 311 of the cam protrusions 310 . Two rollers 420 of the cam follower 400 are disposed at intervals of 180 degrees.
[0028] The cam follower 400 is assembled with an accelerating member 500 and is installed at the pump body 100 . The accelerating member 500 includes a spline boss 530 and is coupled to the pump body 100 via a spline shaft 520 so as to make a linear motion (ascending/descending motion in the present embodiment) approaching the cam member 400 and not to allow relative rotation of the cam follower 400 . An elastic member 600 is disposed between the accelerating member 500 and the pump body 100 and provides an elastic force so that the elastic member 600 may be moved relative to the accelerating member 500 to approach the cam member 300 . In the present embodiment, the elastic member 600 having a shape of a spring 600 is used. The cam follower 400 that is disposed between the accelerating member 500 and the cam member 300 , receives the elastic force of the elastic member 600 from the accelerating member 500 and is maintained to be closely adhered to the cam member 300 .
[0029] The accelerating member 500 and the cam follower 400 are assembled with each other so that they may rotate relative to each other within a predetermined angle range. Due to interaction between accelerating protrusions 410 formed on the cam follower 400 and angle limiting portions 510 formed on the accelerating member 500 , the accelerating member 500 and the cam follower 400 may be rotated relative to each other within the predetermined angle range. In the present embodiment, the angle limiting portions 510 are long holes that extend in the circumferential direction of the accelerating member 500 . Two angle limiting portions 510 having a shape of long holes face each other in a state where a central axis (operating rod 220 ) of the cam follower 400 is interposed between two angle limiting portions 510 . The accelerating protrusions 410 of the cam follower 400 are formed in the form of rods that extend in a radial direction of the cam follower 400 and protrude from the cam follower 400 . Like the angle limiting portions 510 , two accelerating protrusions 410 are disposed and face each other in a state where the central axis of the cam follower 400 is interposed between two accelerating protrusions 410 . The accelerating protrusions 410 are respectively inserted in the angle limiting portions 510 of the accelerating member 500 . Since the accelerating protrusions 410 are caught in inner walls of the angle limiting portions 510 , the cam follower 400 rotates with respect to the accelerating member 500 within an angle range that is allowed by the angle limiting portions 510 . That is, a relative rotational angle of the cam follower 400 with respect to the accelerating member 500 is limited by interference between the accelerating protrusions 410 and the angle limiting portions 510 . A range of the relative rotational angle of the cam follower 400 with respect to the accelerating member 500 that is limited by interaction between the accelerating protrusions 410 and the angle limiting portions 510 may be greater than 0 degree and less than angle intervals between the cam protrusions 310 . In the present embodiment, a rotatable angle of the cam follower 400 may be greater than 0 degree and less than 90 degrees. The rollers 420 are installed at ends of the accelerating protrusions 410 according to the present embodiment and roll on the inclined surfaces 311 of the cam protrusions 310 of the cam member 300 .
[0030] Hereinafter, an operation of the valve accelerating type dispensing pump having the above structure of FIGS. 1 through 3 will be described.
[0031] FIG. 4 is a cross-sectional view taken along a line IV-IV of the valve accelerating type dispensing pump of FIG. 1 , and FIGS. 5A , 5 B, 6 A, 6 B, 7 A, and 7 B are schematic views for explaining an operation of the valve accelerating type dispensing pump of FIG. 1
[0032] Referring to FIG. 4 , the liquid stored in the external syringe flows to the reservoir 112 of the valve body 110 via the inlet path 111 under uniform pressure.
[0033] If the motor 910 operates in this state, the motor 910 rotates with the driving pulley 920 , and the driven pulley 940 that is connected to the driving pulley 920 via the timing belt 930 , also rotates. The cam member 300 that is coupled to the driven pulley 940 rotates with the driven pulley 940 .
[0034] If the cam member 300 rotates, the rollers 420 of the cam follower 400 roll along the inclined surfaces 311 of the cam protrusions 310 , and the cam follower 400 ascends. Since the accelerating member 500 is spline-coupled to the pump body 100 via the spline shaft 520 , the accelerating member 500 does not rotate but the rollers 420 roll along the inclined surfaces 311 of the cam protrusions 310 so that the accelerating member 500 and the cam follower 400 ascend. When the accelerating member 500 ascends, the elastic member 600 is pressurized while applying the elastic force to the accelerating member 500 in a downward direction. Due to the elastic force of the elastic member 600 , the rollers 420 of the cam follower 400 are maintained in contact with a top surface of the cam member 300 . The operating rod 220 that is coupled to the cam follower 400 , ascends with the valve rod 210 . When the valve rod 210 ascends, the liquid flows in a space formed in the reservoir 112 , and the space is filled with the liquid.
[0035] Referring to FIGS. 1 , 5 A, and 5 B, when the cam member 300 rotates, the accelerating protrusions 410 of the cam follower 400 are slid along the angle limiting portions 510 of the accelerating member 500 and are caught in left walls of the angle limiting portions 500 based on FIGS. 5A and 5B . Thus, rotation of the cam follower 400 does not proceed any more. That is, even when the cam member 300 rotates, the cam follower 400 does not rotate with respect to the accelerating member 500 . A concept of a state of force balance between the cam follower 400 and the cam member 300 is as shown in FIGS. 5A and 5B . A vertical resistance F R applied to the rollers 420 on the inclined surfaces 311 of the cam protrusions 310 is balanced with a horizontal component force F H and a vertical component force F V that are applied to the rollers 420 . The vertical component force F V is provided by the elastic member 600 and is transferred to the rollers 420 via the accelerating member 500 . The horizontal component force F H is transferred to the rollers 420 via the pump body 100 —the accelerating member 500 —the cam follower 400 , because the accelerating protrusions 410 are caught in the angle limiting portions 510 .
[0036] If the rollers 420 roll up to tops of the inclined surfaces 311 of the cam protrusions 310 and ascend, the horizontal component of the vertical resistance F R that is balanced with the horizontal component force F H applied to the rollers 420 becomes extinct, as illustrated in FIGS. 6A and 6B . That is, on the inclined surfaces 311 of the cam protrusions 310 , a force is applied to the rollers 420 in the horizontal direction, and any force other than a frictional force is not applied to the rollers 420 in the vertical direction. As a result, due to the horizontal component force F H applied by the angle limiting portions 510 to the accelerating protrusions 410 , the rollers 420 bounce off the cam protrusions 310 in the circumferential direction (right direction in FIGS. 5A , 5 B, 6 A, 6 B, 7 A, and 7 B) of the cam member 300 , as illustrated in FIGS. 7A and 7B . As described above, since the cam follower 400 may rotate with respect to the accelerating member 500 within the angle range that is allowed by the angle limiting portions 510 , the cam follower 400 rotates with respect to the accelerating member 500 that does not rotate, in an opposite direction to a rotation direction of the cam member 300 , and the rollers 420 escape from the tops of the cam protrusions 310 at high speed. In this case, due to the elastic force of the elastic member 600 , the accelerating member 500 , the cam follower 400 , the operating rod 220 , and the valve rod 210 descend. As a result, the liquid filled in the reservoir 112 is pressurized by the valve rod 210 and is discharged via the discharge path 113 .
[0037] If the cam member 300 rotates consecutively and the rollers 420 ascend and descend along the cam protrusions 310 repeatedly, the valve rod 210 ascends and descends consecutively so that the liquid may be discharged via the discharge path 113 .
[0038] In the above liquid-pumping mechanism, the descending speed of the valve rod 210 greatly affects the discharge amount and discharge speed of the liquid. In order to adjust an accurate discharge amount, an inner diameter of the discharge path 113 may be relatively small. As the descending speed of the valve rod 210 increases, the liquid having high viscosity may be quickly dispensed via the discharge path 113 having a small inner diameter. In particular, when the viscosity of the liquid is high, if the descending speed of the valve rod 210 is not sufficiently high, due to resistance caused by viscosity and resistance of the discharge path 113 , the liquid may not be discharged. However, like in embodiments of the present invention, the accelerating member 500 is used so that a liquid having high viscosity may be dispensed. In this way, by using the valve accelerating type dispensing pump according to embodiments of the present invention, the range of the liquid that may be dispersed, may be greatly increased.
[0039] When there is no interaction between the accelerating protrusions 410 and the angle limiting portions 510 as described above, the descending speed of the valve rod 210 is determined by a rotational speed of the cam member 300 . As illustrated in FIGS. 6A and 6B , the rollers 420 should roll toward the cam member 300 by a distance D indicated in FIG. 7A so that the rollers 420 may be moved from the tops of the cam protrusions 310 to the lowermost portion of the top surface of the cam member 300 , as illustrated in FIGS. 7A and 7B . In a valve dispensing pump having no accelerating member including angle limiting portions according to the related art, since a cam member should rotate in a state where a cam follower is fixed and rollers should roll up to a bottom surface of the cam member, the descending speed of the valve rod is determined by the rotational speed of the cam member. Even when an elastic member that provides a strong elastic force is used, the descending speed of the valve rod is substantially determined by the rotational speed of the cam member rather than the elastic force of the elastic member. In particular, when an outer diameter of each roller increases, a distance that is required for the rollers to contact the lowermost portion of the top surface of the cam member, increases so that the descending speed of the valve rod is also decreased by the distance.
[0040] However, in the valve accelerating type dispensing pump according to the present embodiment, when the rollers 420 roll along the inclined surfaces 311 of the cam protrusions 310 , the angle limiting portions 510 push the accelerating protrusions 410 in an opposite direction to the rotation direction of the cam member 300 by using the horizontal component force F H applied to the rollers 420 , as illustrated in FIGS. 6A and 6B . The cam follower 400 rotates with respect to the accelerating member 500 due to a force applied by the angle limiting portions 510 to the accelerating protrusions 410 and rotates instantaneously in an opposite direction to the rotation direction of the cam member 300 , as illustrated in FIGS. 7A and 7B . As a result, the rollers 420 and the cam member 300 are moved in opposite directions, and the rollers 420 roll at much higher speed compared to the related art by the distance D at which the rollers 420 contact the lowermost portion of the top surface of the cam member 300 . Even when the rollers 420 having a relatively large outer diameter are used, due to interaction between the accelerating protrusions 410 and the angle limiting portions 510 , the rollers 420 may be moved relative to the cam member 300 at high speed, and the valve rods 210 may descend due to the elastic member 600 at very high speed. Since the momentum and kinetic energy of the valve rod 210 are proportional to a descending speed of the valve rod 210 and a square of the descending speed, the liquid may be dispensed at much higher speed compared to the related art. In particular, a liquid having high viscosity may be dispensed by a sufficient force via the discharge path 113 having a relatively small inner diameter.
[0041] If the rollers 420 contact next cam protrusion 310 , the cam follower 400 that rotates with respect to the accelerating member 500 in an opposite direction to the cam member 300 , rotates in the same direction as the rotation direction of the cam protrusions 310 due to the vertical resistance F R of the cam protrusions 310 , and the accelerating protrusions 410 are caught in the angle limiting portions 510 in a progressive direction. When the angle range of the angle limiting portions 510 is less than the angle range between the cam protrusions 310 , the accelerating protrusions 410 are first caught in inner walls of the angle limiting portions 510 , and rotation of the cam follower 400 with respect to the accelerating member 500 stops. If the rollers 420 contact next cam protrusion 310 , the cam follower 400 rotates in the same direction as the cam member 300 so that the accelerating protrusions 410 are caught in opposite inner walls of the angle limiting portions 510 and rotation of the cam follower 400 stops.
[0042] To sum up, in the related art, even when an elastic force of an elastic member is strong, the descending speed of the valve rod is determined by the size of an outer diameter of a roller and a rotational speed of a cam member. However, in the valve accelerating type dispensing pump according to embodiments of the present invention, due to interaction between the angle limiting portions 510 and the accelerating protrusions 410 , the descending speed of the valve rod 210 may be increased using a sufficient elastic force of the elastic member 600 .
[0043] Although embodiments of the present invention have been described as above, the scope of the present invention is not limited to the above-described embodiments.
[0044] For example, the accelerating protrusions 410 are formed on the cam follower 400 , and the angle limiting portions 510 are formed on the accelerating member 500 . However, the accelerating protrusions 410 may be formed on the accelerating member 500 , and the angle limiting portions 510 may be formed on the cam follower 400 .
[0045] Also, a bearing that rolls along the inner walls of the angle limiting portion 510 may be installed at the accelerating protrusions 410 so as to reduce friction between the accelerating protrusion 410 and the angle limiting portion 510 .
[0046] In addition, the angle limiting portions 510 have the shape of long holes, as described above. However, the angle limiting portions 510 may also be formed in the form of long grooves. The accelerating protrusions 410 and the angle limiting portions 510 may be formed in various shapes in which the accelerating member 500 and the cam follower 400 may rotate relative to each other within a predetermined angle range due to interference between the accelerating protrusions 410 and the angle limiting portions 510 .
[0047] Furthermore, the rollers 420 are installed at the accelerating protrusions 410 , as described above. However, the rollers 420 may be configured in different ways. The accelerating protrusions 410 interfere with the angle limiting portions 510 independently from the rollers 420 so that the rotational angle of the cam follower 400 may be limited, and the rollers 420 may be configured to be coupled to the cam follower 400 separately from the accelerating protrusions 410 .
[0048] FIG. 8 illustrates another example of accelerating protrusions 551 and angle limiting portions 452 .
[0049] The accelerating protrusions 551 are formed on an accelerating member 550 , and the angle limiting portions 452 are formed on a cam follower 450 . The angle limiting portions 452 of the cam follower 450 are formed in the form of long grooves having a circular arc shape on a surface that faces the accelerating member 550 along a circumferential direction of the accelerating member 550 . The accelerating protrusions 551 of the accelerating member 550 are formed in the form of rods that extend in a bottom surface of the accelerating member 550 and are inserted in the angle limiting portions 452 of the cam follower 450 . The cam follower 450 rotates with respect to the accelerating member 550 slightly, and the accelerating protrusions 551 are caught in the inner walls of the angle limiting portions 452 such that the cam follower 450 does not rotate any more. The remaining configuration of the accelerating protrusions 551 and the angle limiting portions 452 excluding the above configuration is the same as FIGS. 1 through 7A and 7 B. If rollers 451 of the cam follower 450 roll along cam protrusions 310 in a state where the angle limiting portions 452 are caught in the accelerating protrusions 551 and the cam follower 450 cannot rotate, the angle limiting portions 452 are pushed by the accelerating protrusions 551 so that the cam follower 450 rotates with respect to the accelerating member 550 . As such, the relative speed between the rollers 451 and the cam member 300 increases, and the valve rod 210 may descend at high speed.
[0050] In the present embodiment, eight cam protrusions 310 and two rollers 420 are disposed. However, the number of cam protrusions 310 and the number of rollers 420 may be diverse. The shape of the cam protrusions 310 may vary according to their inclined angles and curvatures of inclined surfaces.
[0051] As described above, in a valve accelerating type dispensing pump according to embodiments of the present invention, an accurate amount of a liquid may be dispensed at high speed.
[0052] Also, the valve accelerating type dispensing pump according to embodiments of the present invention may dispense a liquid having high viscosity at high speed due to a fast descending speed of a valve rod.
[0053] While embodiments of the present invention have been particularly shown and described, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.
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A dispensing pump, and more particularly, a valve accelerating type dispensing pump that may be used in a process of manufacturing an electronic product and may dispense an accurate amount of a liquid, such as a liquid synthetic resin, at high speed. The valve accelerating type dispensing pump can descend a valve rod at high speed and thus can dispense a liquid with high viscosity at high speed. The valve accelerating type dispensing pump can dispense an accurate amount of a liquid at high speed. Also, the valve accelerating type dispensing pump can dispense a liquid having high viscosity at high speed due to a fast descending speed of a valve rod.
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CROSS-REFERENCE TO A RELATED APPLICATION
[0001] This application is a continuation-in-part of application Ser. No. 09/057,797 filed Apr. 9, 1998, which is a continuation-in-part of application Ser. No. 08/982,770 filed Dec. 2, 1997 and converted to a provisional application Apr. 9, 1998 which was a continuation-in-part of Ser. No. 08/839,393 filed Apr. 11, 1997 and converted to a provisional application Apr. 1, 1998.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a carrier for transporting vehicles by placing a vehicle on a platform deck, or bed, and transporting that vehicle to a desired location.
[0003] In some situations, it is desirable to carry a vehicle, as opposed to towing that vehicle in a conventional manner. These situations include when the vehicle to be towed is severely damaged and perhaps missing an axle or when the owner of an automobile wishes to transport the same over a greater than average distance. The carrier found in the prior art typically includes a platform deck or bed carried on a truck chassis. The bed is capable of moving rearwardly away from the chassis and can then incline down to the ground into a vehicle loading position. In the vehicle loading position, the bed forms a ramp onto which the vehicle can be winched, driven, or placed thereon by other conventional techniques.
[0004] At the present time, there are several disadvantages associated with the prior art to which this patent application is addressed. For example, it is crucial that the angle between the bed and the ground be as small as possible. This angle is known as the approach or load angle. The lower the angle of incline on the bed, the easier it becomes to load a vehicle to be towed, especially given modern vehicles low ground clearance and the longer nose of older automobiles. Given the variety of different vehicle configurations, a lower bed angle, or approach angle, is desirable.
[0005] In the past, carrier operators have solved the problem of approach angles with make-shift methods is such as ramps and wood planks. These are cumbersome and difficult to store.
[0006] Another problem associated with the prior art is that the winch cable which may be used to pull the vehicle to be towed onto the bed is often undirected and given the variety of approach angles necessary, the winch cable may cause damage to the vehicle to be towed. Although hinged beds have been used in Europe primarily, they did not have the benefits of a conventional deck and caused severe damage with their cables should a tow hook not be provided on the automobile. Two hooks are uncommon on automobiles in the United States and damage is common with a winch cable. This problem is exasperated with the addition in modern automotive design of low profile automobiles having ground effects such as air dams which could interfere in the direction of the cable.
SUMMARY OF THE INVENTION
[0007] The present invention is directed to a uniquely constructed carrier that overcomes the disadvantages associated with prior art devices. The present invention is a car carrier that includes a bed that is hinged or articulable such that the approach angle of the carrier is substantially minimized. Because the bed of the present invention is hinged, the rear plate of the bed can be moved to a position adjacent the vehicle to be towed in a lower angle than that found in the prior art. In addition, because the bed is hinged, a cable guide is provided that directs the cable along the bed, thereby eliminating any interference with ground effects of the vehicle to be towed. The bed can also be locked in a position for use as a conventional carrier. The carrier is outfitted conventionally to include a wheel lift or underlift for towing a second automobile and the advantages are achieved by means of a relatively simple and cost effective, reliable design. As a result, the carrier of the present invention provides damage free operation and is more versatile than known prior art carriers.
[0008] It is, therefore, an object of this invention to provide a carrier whereby a vehicle to be towed may be loaded and moved so that no additional damage will result to the vehicle.
[0009] Another object of this invention is to provide a carrier that includes a bed capable of reducing the load or approach angle when a vehicle to be towed is loaded.
[0010] A further object of this invention is to provide a carrier with a cable guide so that winch cable used to load the vehicle to be towed onto the bed cannot cause further damage thereto.
[0011] A still further object of this invention is to provide a carrier that can be use in a conventional manner, as well as in a hinged fashion.
BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWINGS
[0012] [0012]FIG. 1 is a perspective view of the carrier of the present invention showing the bed extended and in the loading position.
[0013] [0013]FIG. 2 is a side elevation showing the carrier with the bed in the extended and loading position relative to a vehicle to be towed.
[0014] [0014]FIG. 3 is a side elevation taken from box 3 - 3 of the FIG. 2.
[0015] [0015]FIG. 4 is a side elevation showing the vehicle in an extended and loading position with the vehicle to be towed positioned on the first stage of the bed.
[0016] [0016]FIG. 5 is a side elevation showing the carrier having the bed in the extended position and the vehicle to be towed is located entirely on the bed.
[0017] [0017]FIG. 6 is a side elevation with the bed in the carrying position.
[0018] [0018]FIG. 7 is an exploded perspective view of the cable guide found in the bed of the carrier.
[0019] [0019]FIG. 7A is a side view of the cable guide.
[0020] [0020]FIG. 8 is a perspective view of the underside of the carrier showing one embodiment of the locking mechanism to prevent the bed from hingeable movement when desired. FIG. 8 shows the locking mechanism which has two independent locks, one on each side of the bed.
[0021] [0021]FIG. 9 is a view of the plunger lock from underneath the carrier. This plunger lock is used in the embodiment shown in FIG. 8.
[0022] [0022]FIG. 10 is a side sectional of the rear portion of the bed.
[0023] [0023]FIG. 11 is a close up view taking from circle 11 - 11 of FIG. 9.
[0024] [0024]FIGS. 12 and 13 are underside views of the second embodiment of the locking mechanism. FIG. 12 shows the locking mechanism which has one handle for releasing both plunger locks.
[0025] [0025]FIG. 14 is an elevational exploded view of the present invention also shown in FIG. 12.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0026] Referring to the drawings, and more particularly to FIG. 2, the carrier 10 of the present invention includes a cab 12 and chassis 14 . It is anticipated that the invention is adaptable both to a single axle chassis (as shown in FIG. 1) as well as a multiple axle chassis (as shown in FIG. 2). The bed 16 is mounted on the chassis (on a sub-frame not shown) and is capable of movement horizontally as well as provided with a hydraulic tilt mechanism 18 which tilts the bed 16 about a pivot (not shown). The vehicle to be towed 20 is also shows on FIG. 2.
[0027] Likewise, as in conventional carriers, carrier 10 is provided with an underlift or wheel lift 22 which is capable of towing a vehicle not positioned on bed 16 . Bed 16 includes a front section 24 and a rear section 26 . Bed 16 is also provided with a winch 28 and a cable 30 . Cable guide 32 directs cable 30 along the surface of an articulated or hinged bed 16 .
[0028] The structure of the bed 16 is best shown in detail views contained in FIGS. 9 through 11. FIG. 9 shows the underside of bed 16 . As mentioned previously, the front section 24 of bed 16 and rear section 26 of bed 16 are connected by a series of hinges 34 , as best shown in FIG. 11. Hinges 34 are comprised of a front hinge bar 36 and a rear hinge bar 38 . Front hinge bar 36 is welded to the front section 24 of bed 16 . Rear hinge bar 38 is welded to rear section 26 of bed 16 .
[0029] These hinge bars 36 , 38 are positioned on the sections of the bed 24 , 26 such that they line up as shown in FIG. 11. A bore is positioned at the end of each hinge bar 36 , 38 so that a greasable hinge pin 40 will be positioned therethrough and provide an axis for hinged movement of the hinge bars 36 , 38 . The hinge bars 36 , 38 are rounded at the end through which the pin 40 passes. Pin 40 is provided with an internal bore- 42 adapted to receive a grease fitting. Bore 42 branches off and, when grease is applied into the fitting, bars 36 , 38 are greased at their respective pivot points. Cotter pin 44 is positioned through pin 40 for securement. There are five of these hinges 34 disposed along the fold line 46 of the bed 16 .
[0030] The support structure of the rear section 26 of bed 16 is best shown in FIG. 10. Bed 16 includes front side rails 48 and rear side rails 50 . Also included is front floor plate 52 and rear floor plate 54 . Support tubing 56 is attached thereto for added strength. Beam 58 is primarily attached to the rear section 26 of bed 16 and extends forward beyond hinges 34 so that when the bed 16 is in a flat or linear orientation, beam 58 contacts front section 24 of bed 16 to prevent rear section 26 from folding downwardly or beyond a planar relation between the front floor plate 52 and the rear floor plate 54 . Beam 58 also includes aperture 60 for receiving the cam lock means described below. A second coaxial aperture 62 is located in a fixed position on the front section 24 of bed 16 .
[0031] The locking mechanism is best described by viewing FIGS. 8 and 9. In order to prevent the bed 16 from moving in a hingeable fashion when such movement is not desired, the present invention provides a plunger lock on each side of the bed to fix the bed in a conventional orientation. Lock 64 is comprised of a lock control rod 66 that has a handle 68 placed adjacent the front side rails 48 to enable an operator to actuate the locking mechanism. A cam lock 70 of the type known in the prior art is provided at the end of the lock control rod 64 opposite handle 68 . By turning lock control handle 68 , the cam lock pin 72 is retracted allowing the rear section 26 of bed 16 to pivot on its hinges 34 . Cam lock pin 72 extends into apertures 60 and 62 preventing movement when engaged.
[0032] The cable guide 32 is disposed in the front floor plate 52 and is removably attached through a keyhole 74 in a housing box contained in the floor plate. The cable guide 32 is comprised of a pair of oppositely oriented hooks 76 welded to a T-shaped key 78 . The T-shaped key member 79 is adapted to be positioned through keyhole 74 and rotated to a operative position such that cable 30 would extend longitudinally along bed 16 when disposed through the hook 76 . Cable guide 32 remains rotatable within keyhole 74 , and can be removed by rotating cable guide 32 to line up the T-shaped member 78 with keyhole 74 , or 90 degrees. The cable guide 32 may be constructed from a single manufacture or by welding or otherwise joining the various elements together.
[0033] In operation, and when used as a hinged bed, bed 16 is lowered and moved to a position as shown in FIG. 2 adjacent the vehicle to be towed 26 . When the rear section 26 of the bed 16 is hinged, the approach angle is approximately 6 degrees.
[0034] Cable 30 is then strung through cable guide (as shown in FIG. 1) and attached to a tow hook or other structure underneath the vehicle to be towed 20 . Without cable guide 32 , the dotted line 94 in FIGS. 2 and 3 shows the path that the cable would travel from the winch 28 to the vehicle to be towed 20 . Should the cable 30 not be threaded through cable guide 32 before attachment to the vehicle, it may be possible to damage the vehicle to be towed 20 due the relative angle of bed 16 and cable 30 .
[0035] Once the vehicle to be towed 20 is attached to cable 30 , the vehicle to be towed 20 can be moved to a first position wherein its front wheels are located on the rear section 26 of bed 16 . At this point, cable guide 32 can be removed from grommet 74 (as shown in FIG. 4) and the vehicle to be towed 20 can be moved forwardly along bed 16 as shown in FIG. 5. Prior to movement of the vehicle to be towed forwardly, the bed is moved to a second position where, although still inclined, the angle between the rear section 26 and front section 24 is eliminated thereby providing a planar relationship between front section 24 and rear section 26 of bed 16 . At this point, bed 16 may be locked in this planar position. The vehicle can then moved forward to its foremost position.
[0036] As shown in FIG. 6, the vehicle to be towed 20 is in its foremost position. When it is safe and feasible, the bed can be lowered to this stored or carrying position and the vehicle to be towed 20 can be locked and secured to the bed. For example, the vehicle can be tied down by threading chains through eyelets 94 when fully secured, the vehicle 20 can be taken to its intended destination.
[0037] An alternative and preferred embodiment of the present invention is shown in FIGS. 12 through 14. In contrast with the first embodiment, shown best in FIGS. 8 and 9, which require that an operator go to each side of the bed in order to separately unlock the two independent lock control rods 64 , the second embodiment, best shown in FIGS. 12 and 13, requires that the operator only unlock a single handle located on the driver's side of the carrier bed. As shown in FIGS. 12 and 13, the carrier 10 has two connected lock pins 100 , 102 . Driver side lock pin 100 is connected by linkage 104 to clevis 106 . Clevis 106 is connected to the linkage control arm 108 in a pivotable fashion. Linkage control arm 108 pivots around point 110 .
[0038] When actuated by an operator, control arm 108 travels about point 110 along path 112 . The linkage control arm 108 is also connected to the center linkage 114 . Movement of the linkage control arm 108 along path 112 to a disengaged position causes center linkage arm 114 to disengage the passenger side lock pin 102 . Center linkage arm 114 causes the passenger side linkage control arm 116 to disengage the passenger side lock pin 102 by pivoting the passenger side linkage control arm 116 about pivot point 118 by pulling linkage control arm 108 , as shown in FIG. 12, linkage control arm 116 is rotated counterclockwise about point 118 which pulls clevis 120 and linkage 122 , thereby disengaging the passenger side lock pin 102 .
[0039] The disengagement of the passenger side lock pin 102 and the driver side lock pin 100 is accomplished at an approximate simultaneous time so that both lock pins are disengaged to allow the hinged portion of carrier bed 10 to pivot freely. The driver side linkage control arm 108 , when the lock pins 100 , 102 are disengaged, sticks out from the side of the carrier 10 so as to be obviously unlocked and gives a visual signal by its location that the hinged bed is not locked in planar position. This position of the linkage control arm 108 is shown best in FIG. 13 as the unlocked or disengaged position. Position pin 124 is positioned and shaped to guide the driver side linkage control arm 108 to a locked position when the lock pins 100 , 102 are engaged. Position pin 124 is guided on linkage control arm 108 in cutout 126 .
[0040] Although the figures show both a single axle and tandem axle chassis, the invention is not limited to any particular chassis style or arrangement.
[0041] Thus, an improved carrier is disclosed having a hinged bed capable of being locked in a planar orientation and provided with a cable guide to maximize the advantage of having an articulated bed without causing damage to the vehicle to be towed. From the foregoing, it will be observed that numerous variations and modifications may be affected without departing from the true spirit and scope of the novel concept of the present invention. It will be understood that no limitation with respect to the specific embodiment illustrated herein is intended or should be inferred. The terms and expressions which have been employed herein are used our terms of description now limitation, and there is no intention in the use of such terms and expressions, of excluding any equivalents of the future shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention now claimed.
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An improved carrier which includes a hinged bed in order to decrease the load or approach angle on vehicle to be towed. The carrier also includes a lock which can hold the bed in a flat or planar position as a conventional straight deck, and a cable guide which directs the tow cable along the surface of the articulated bed to avoid contact with the vehicle to be towed.
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CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims the priority benefit of U.S. provisional patent application No. 60/827,677 filed Sep. 29, 2006 and entitled “Axial Flow Fan” and U.S. provisional patent application No. 60/950,610 filed Jul. 19, 2007 and entitled “Surface Profile for a Quiet Rotor or Stator.” The disclosure of these commonly owned applications are incorporated herein by reference.
This application is related to U.S. Pat. No. 5,934,877 for a “Rotor with Logarithmic Scaled Shape” and U.S. Pat. No. 6,702,552 for an “Impeller Having Blade(s) Conforming to the Golden Section of a Logarithmic Curve.” The disclosures of these commonly owned patents are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally concerns axial flow fans and rotors. More specifically, the present invention concerns a surface profile for axial flow fans and rotors used in environments requiring high output in conjunction with constrained fan size including but not limited to electronics cooling.
2. Description of the Related Art
Fan and rotor design has undergone little change over the past century. As a result, fans and rotors remain relatively inefficient. A part of this inefficiency is the result of fans and rotors generating a considerable amount of noise and turbulence. Similarly, fans and rotors used in liquid environments typically result in cavitation. Noise, turbulence, and cavitation reduce the operational efficiency of the fan and rotor.
A chart illustrating inefficiencies with respect to flow and sound in a series of 92×38 mm computer fans as found in the prior art are shown in FIG. 1A . A similar chart illustrating inefficiencies with respect to flow and torque in prior art fan design is shown in FIG. 1B . FIG. 1B illustrates, specifically, a 22″ best-in-class A/C fan with a standard bell shroud operating at 850 rpm.
Much of the noise, turbulence, and unwanted torque in prior art fan design may be attributable to the surface design of the fan or rotor. In many instances, fans and rotors are implemented in a particular operating environment based on a pre-existing design. These pre-existing designs are not necessarily designed or intended for that particular operating environment. Nevertheless, these pre-existing designs may achieve results that are adequate or ‘good enough’ for that particular environment.
Determining which pre-existing design is adequate or ‘good enough’ for a particular environment is a never-ending exercise. Trial and error will continually redefine the best adequate or ‘good enough’ design implementation. Notwithstanding these adequate results, some degree of the aforementioned noise, turbulence, and/or unwanted torque will inevitably remain.
There is, therefore, a need in the art for fan and rotor design where the surface profile may be configured to desired dimensions particular to a given operating environment.
SUMMARY OF THE INVENTION
Embodiments of the present invention provide for an axial flow fan that is quieter for the same or better output throughout a range of operating points compared to prior art fan designs. References to an axial flow fan or any fan are meant to be inclusive with respect to rotors and other blade designs.
In one exemplary embodiment, a method for constructing an axial fan is disclosed. In this exemplary method, a spline is drafted to connect a plurality of points along a radius cut sketch to form a blade surface. The blade surface is then offset by a constant amount and filled to form a single blade. The single blade is oriented with respect to a hub and patterned along with a total number of blades to be affixed to the hub. The single blade and remaining blades are then attached to the hub.
In another embodiment, a fan apparatus is disclosed. The fan apparatus includes a hub a blade coupled to the hub, the blade including a blade surface. The blade surface is created by drafting a spline to connect a plurality of points along a radius cut sketch. The blade is created by offsetting the blade surface by a constant amount and filling the blade surface to form a single blade.
Another exemplary method provides for constructing an axial fan. The exemplary method includes drafting a spline to connect a plurality of points along a radius cut sketch to form a blade surface. A complimentary airfoil shape is then created. The airfoil is then lofted into a solid.
A computer-readable storage medium is also disclosed. The medium has embodied thereon a program being executable by a processor to perform a method for constructing an axial fan.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A is a chart exhibiting flow and sound inefficiencies in prior art fan design.
FIG. 1B is a chart exhibiting flow and torque inefficiencies in prior art fan design.
FIG. 2A is a chart exhibiting flow and sound efficiency of a fan as may be designed in accordance with an exemplary embodiment of the present invention as compared to the inefficiencies of prior art fans like those shown in FIG. 1A .
FIG. 2B is a chart exhibiting flow and torque efficiency of a fan as may be designed in accordance with an exemplary embodiment of the present invention as compared to the inefficiencies of a prior art fan like that shown in FIG. 1B .
FIG. 3 illustrates an exemplary fan and surface profile according to an embodiment of the present invention.
FIG. 4 illustrates an exemplary surface profile of a fan blade according to an alternative embodiment of the present invention.
FIG. 5 illustrates an exemplary method for constructing a blade surface according to an embodiment of the present invention.
FIG. 6 illustrates a method for forming a blade according to an embodiment of the present invention.
FIG. 7 illustrates an alternative method for forming a blade according to an embodiment of the present invention.
FIG. 8 illustrates an exemplary method for constructing a fan according to an embodiment of the present invention.
FIGS. 9A-9E illustrate exemplary fans constructed utilizing the surface profile disclosed with respect to FIG. 3 .
FIGS. 10A-10E illustrate exemplary fans constructed utilizing the surface profile disclosed with respect to FIG. 4 .
DETAILED DESCRIPTION
Embodiments of the present invention provide for a fan that is quieter for the same or better output throughout a range of operating points compared to prior art fan designs. FIG. 2A is a chart exhibiting flow and sound efficiency of an exemplary fan as may be designed in accordance with the present invention compared to the inefficiencies of a prior art fan like that found in FIG. 1A . FIG. 2B , in turn, is a chart exhibiting flow and torque efficiency of an exemplary surface profile as may be designed for a fan in accordance with the present invention compared to the inefficiencies of a prior art fan like that found in FIG. 1B .
FIG. 3 illustrates a portion of an exemplary fan 300 and surface profile 330 according to an embodiment of the present invention. Fan 300 may be motor driven or subject to the natural flow of a fluid (e.g., liquid or gas). Fan 300 includes a hub 310 , which may be approximately cylindrical or conical in shape. Hub 310 may be hollowed like that of FIG. 9A or solid as is shown in FIG. 10E . Hub 310 may also include a cap like that shown in FIG. 9B . Hub 310 may be altered with radii, chamfers, and/or blends with symmetry about the Y-axis as illustrated throughout FIGS. 9 and 10 . Hub 310 may be configured to an appropriate height and diameter in order to incorporate a desired motor and hub-tip ratio as illustrated throughout FIGS. 9 and 10 .
Blades 320 are circularly patterned around hub 310 . Blades 320 may be permanently or temporarily coupled or affixed to the hub 310 through various techniques as known in the art. The surface profile 330 of blades 320 may be configured in accordance with the various profiles described in U.S. Pat. Nos. 5,934,877 and 6,702,552, the disclosure of which has been previously incorporated herein by reference. For example, a portion of the surface profile 330 of fan blade 320 may conform to a logarithmic spiral. The radius of that particular logarithmic spiral may unfold at a constant order of growth when measured at equiangular radii, which may sometimes be referred to as the Golden Section.
Surface profile 330 configurations may also correspond to external or internal shell configurations as found in nature. For example, the surface profile 330 of blade 320 may conform to the shell of the phylum Mollusca, class Cephalopoda, genus Nautilus . An alternative surface profile-to-shell configuration may be inclusive of the shell shaping of the phylum Mollusca, class Gastropoda, genus Conus, Conidae, Turbinidea , or Volutidae . Shell configurations from other members of phylum Mollusca, class Gastropoda or Cephalopoda may also be implemented with respect to the surface profile 330 of blade 320 .
Various other surface configurations may be implemented in accordance with embodiments of the present invention. For example, surface profile 330 of blade 320 may be defined by the following tables. In Tables I-IX, Cartesian points are taken at even intervals along the span of the blade, which corresponds to an 87 mm diameter fan. In the context of FIG. 3 , axis Y represents the hub axis and serves as the zero reference for all radial measurements. All dimensions in Tables I-IX are in millimeters. The blade surface may be constructed through a method like that disclosed in the context of FIG. 5 .
TABLE I
22.5 mm Radius
Pt #
X
Y
Z
1
−5.389
−2.463
21.845
2
−2.804
−0.447
22.325
3
−1.548
0.621
22.447
4
−0.338
1.725
22.497
5
4.187
6.381
22.107
6
6.236
8.883
21.619
7
8.171
11.467
20.964
8
9.981
14.098
20.165
9
11.645
16.791
19.252
10
12.675
18.611
18.590
TABLE II
25 mm Radius
Pt#
X
Y
Z
1
−6.755
−3.085
24.070
2
−5.230
−1.984
24.447
3
−3.708
−0.850
24.723
4
−2.209
0.344
24.902
5
−0.743
1.590
24.989
6
0.680
2.866
24.991
7
2.072
4.159
24.914
8
4.740
6.826
24.547
9
7.203
9.653
23.940
10
9.536
12.571
23.110
11
11.695
15.578
22.096
12
13.656
18.668
20.941
TABLE III
27.5 mm Radius
Pt #
X
Y
Z
1
−8.339
−3.663
26.205
2
−6.681
−2.508
26.676
3
−5.014
−1.334
27.039
4
−3.379
−0.118
27.292
5
−1.774
1.140
27.443
6
−0.200
2.438
27.499
7
1.360
3.757
27.466
8
2.898
5.107
27.347
9
4.395
6.508
27.147
10
5.841
7.963
26.873
11
7.233
9.452
26.532
12
9.896
12.488
25.658
13
12.351
15.634
24.571
14
14.594
18.869
23.308
TABLE IV
30 mm Radius
Pt #
X
Y
Z
1
−10.052
−4.175
28.266
2
−8.259
−2.972
28.841
3
−6.454
−1.744
29.298
4
−2.895
0.799
29.860
5
−1.145
2.119
29.978
6
0.589
3.464
29.994
7
2.300
4.847
29.912
8
3.968
6.289
29.736
9
5.597
7.786
29.473
10
7.177
9.315
29.129
11
10.171
12.444
28.223
12
11.578
14.055
27.676
13
12.919
15.705
27.076
14
15.426
19.108
25.730
TABLE V
32.5 mm Radius
Pt #
X
Y
Z
1
−11.904
−4.628
30.241
2
−8.077
−2.121
31.480
3
−6.134
−0.832
31.916
4
−4.200
0.476
32.227
5
−0.387
3.180
32.498
6
3.326
6.035
32.329
7
5.121
7.551
32.094
8
6.879
9.111
31.764
9
10.229
12.302
30.848
10
13.307
15.645
29.651
11
16.096
19.177
28.234
TABLE VI
35 mm Radius
Pt #
X
Y
Z
1
−13.944
−5.042
32.102
2
−11.950
−3.756
32.897
3
−9.913
−2.465
33.567
4
−7.835
−1.168
34.112
5
−5.747
0.160
34.525
6
−1.625
2.908
34.962
7
2.419
5.778
34.916
8
4.393
7.286
34.723
9
6.319
8.865
34.425
10
10.022
12.110
33.535
11
11.778
13.779
32.959
12
13.453
15.502
32.311
13
15.045
17.284
31.602
14
16.552
19.129
30.839
TABLE VII
37.5 mm Radius
Pt #
X
Y
Z
1
−16.217
−5.442
33.812
2
−14.137
−4.107
34.733
3
−12.003
−2.783
35.527
4
−9.813
−1.473
36.193
5
−7.592
−0.132
36.724
6
−3.163
2.655
37.366
7
1.205
5.545
37.481
8
3.361
7.039
37.349
9
5.468
8.607
37.099
10
7.519
10.247
36.738
11
9.510
11.916
36.274
12
11.447
13.606
35.710
13
13.311
15.339
35.058
14
15.077
17.149
34.335
15
16.736
19.050
33.558
TABLE VIII
40 mm Radius
Pt #
X
Y
Z
1
−18.694
−5.801
35.363
2
−16.540
−4.436
36.420
3
−14.332
−3.083
37.344
4
−12.065
−1.755
38.137
5
−9.759
−0.412
38.791
6
−7.428
0.970
39.304
7
−5.073
2.390
39.677
8
−0.382
5.301
39.998
9
4.225
8.324
39.776
10
6.454
9.943
39.476
11
8.614
11.644
39.062
12
10.707
13.380
38.540
13
12.752
15.132
37.913
14
14.711
16.945
37.197
15
16.538
18.880
36.421
TABLE IX
42.5 mm Radius
Pt #
X
Y
Z
1
−21.317
−6.090
36.767
2
−19.109
−4.701
37.962
3
−16.842
−3.324
39.020
4
−12.129
−0.612
40.732
5
−9.709
0.774
41.376
6
−7.262
2.199
41.875
7
−2.365
5.103
42.434
8
0.080
6.575
42.500
9
2.514
8.074
42.426
10
4.912
9.640
42.215
11
7.231
11.300
41.880
12
9.460
13.033
41.434
13
11.633
14.797
40.877
14
13.759
16.584
40.211
15
15.754
18.503
39.472
FIG. 4 illustrates an exemplary surface profile 410 of a fan blade 400 according to an alternative embodiment of the present invention. Surface profile 410 may correspond to a blade coupled or affixed to a hub like the fan 300 shown in FIG. 3 . The surface profile 410 of fan blade 400 in FIG. 4 has been defined by the Cartesian points as referenced in Tables X-XXVI (below) and taken at even intervals along the axis of the fan blade 400 . The X, Y, and Z axis are orthogonal to one another and oriented as shown in FIG. 4 . Like tables I-IX, all dimensions are in millimeters.
TABLE X
z = 0 mm
X
Y
−15.143
−23.188
−14.326
−22.832
−13.543
−22.424
−12.092
−21.431
−10.769
−20.241
−9.567
−18.931
−8.467
−17.536
−7.442
−16.078
−5.577
−13.054
−3.900
−9.921
−2.423
−6.683
−1.140
−3.369
0.000
0.000
1.470
5.110
2.078
7.697
2.576
10.311
3.158
15.563
3.063
20.820
2.698
23.451
2.425
24.763
2.094
26.055
0.214
31.012
−0.392
32.199
−1.055
33.364
−2.543
35.567
−4.264
37.579
−6.176
39.433
TABLE XI
z = 5 mm
X
Y
−11.448
−21.282
−10.262
−20.347
−9.220
−19.270
−8.278
−18.093
−7.405
−16.861
−5.804
−14.307
−4.345
−11.667
−3.026
−8.955
−1.861
−6.181
−0.828
−3.356
0.111
−0.493
1.605
4.777
2.219
7.445
2.718
10.142
3.285
15.559
3.152
20.975
2.756
23.684
2.464
25.033
2.110
26.361
0.100
31.441
−0.550
32.655
−1.259
33.838
−2.848
36.059
−4.681
38.070
−6.717
39.906
TABLE XII
z = 10 mm
X
Y
−9.055
−19.049
−8.218
−18.097
−7.448
−17.100
−6.051
−15.004
−4.790
−12.815
−3.650
−10.566
−1.700
−5.933
−0.091
−1.161
1.427
4.243
2.559
9.716
3.150
15.287
3.183
18.115
3.003
20.923
1.906
26.433
1.465
27.782
0.961
29.098
−0.226
31.637
−1.658
34.046
−2.476
35.197
−3.368
36.305
−5.342
38.334
−7.510
40.159
TABLE XIII
z = 15 mm
X
Y
−7.636
−16.833
−6.407
−15.142
−5.294
−13.382
−3.400
−9.666
−1.841
−5.788
−0.520
−1.823
1.028
3.721
2.187
9.359
2.794
15.067
2.623
20.801
2.171
23.646
1.454
26.416
0.460
29.106
−0.142
30.420
−0.810
31.697
−4.123
36.335
−5.129
37.364
−6.209
38.335
−8.496
40.128
TABLE XIV
z = 20 mm
X
Y
−6.748
−14.747
−5.797
−13.336
−4.930
−11.879
−3.443
−8.825
−1.117
−2.431
0.442
3.175
1.607
8.854
2.225
14.633
2.247
17.565
2.033
20.472
1.556
23.345
1.212
24.767
0.793
26.176
−1.576
31.479
−3.193
33.910
−4.118
35.055
−5.109
36.129
−7.282
38.061
−9.650
39.775
TABLE XV
z = 25 mm
X
Y
−6.097
−12.664
−5.414
−11.525
−4.785
−10.362
−3.674
−7.973
−1.861
−3.015
−0.288
2.627
0.863
8.346
1.461
14.168
1.463
17.118
1.220
20.041
0.706
22.931
−0.102
25.770
−1.196
28.484
−2.586
31.057
−3.400
32.287
−4.294
33.466
−6.282
35.609
−8.535
37.464
−10.991
39.098
TABLE XVI
z = 30 mm
X
Y
−5.585
−10.399
−4.067
−7.100
−2.804
−3.695
−1.189
1.944
−0.064
7.667
0.486
13.491
0.463
16.449
0.189
19.383
−0.363
22.272
−0.751
23.699
−1.217
25.108
−3.828
30.353
−4.679
31.560
−5.615
32.715
−7.690
34.793
−10.027
36.564
−12.561
38.097
TABLE XVII
z = 35 mm
X
Y
−5.162
−7.551
−4.098
−4.761
−2.368
0.873
−1.217
6.608
−0.708
12.454
−0.704
13.936
−0.758
15.427
−1.060
18.379
−1.647
21.280
−2.058
22.709
−2.552
24.119
−3.772
26.814
−5.307
29.331
−6.199
30.519
−7.177
31.651
−9.340
33.665
−11.769
35.341
−14.399
36.754
TABLE XVIII
z = 40 mm
X
Y
−4.536
−2.789
−3.114
2.520
−2.292
7.928
−2.135
10.675
−2.170
13.441
−2.907
18.884
−3.250
20.222
−3.664
21.546
−4.704
24.098
−6.028
26.505
−6.800
27.653
−7.645
28.755
−9.517
30.760
−11.648
32.479
−14.038
33.894
−16.570
35.051
TABLE XIX
z = 45 mm
X
Y
−3.952
5.610
−3.744
9.858
−4.047
14.086
−4.411
16.191
−4.929
18.258
−6.455
22.212
−6.949
23.159
−7.488
24.086
−8.690
25.845
−10.056
27.471
−11.599
28.952
−13.298
30.240
−15.124
31.311
−17.062
32.195
−19.063
32.962
TABLE XX
z = −5 mm
X
Y
−19.764
−24.408
−18.389
−24.124
−17.077
−23.624
−14.607
−22.303
−12.354
−20.650
−11.318
−19.698
−10.354
−18.686
−7.038
−14.217
−5.603
−11.812
−4.294
−9.345
−2.231
−4.690
−0.511
0.098
0.964
5.079
2.097
10.148
2.738
15.274
2.712
20.412
2.387
22.987
2.136
24.271
1.829
25.537
0.074
30.408
−0.494
31.579
−1.117
32.730
−2.524
34.917
−4.159
36.924
−5.979
38.785
TABLE XXI
z = −10 mm
X
Y
−21.148
−24.550
−19.540
−23.946
−17.984
−23.240
−15.006
−21.576
−13.608
−20.570
−12.302
−19.447
−9.977
−16.914
−8.556
−14.998
−7.262
−13.011
−4.973
−8.872
−3.030
−4.542
−1.367
−0.074
0.131
4.783
1.301
9.730
2.016
14.737
2.087
19.764
1.814
22.288
1.591
23.550
1.314
24.796
−0.307
29.601
−1.426
31.897
−2.762
34.067
−4.328
36.060
−6.086
37.906
TABLE XXII
z = −15 mm
X
Y
−21.794
−24.790
−20.175
−23.944
−18.591
−23.032
−17.082
−22.071
−15.621
−21.055
−12.915
−18.773
−10.552
−16.093
−8.510
−13.142
−5.128
−6.869
−3.707
−3.589
−2.436
−0.232
−0.930
4.469
0.255
9.261
1.019
14.115
1.181
18.994
0.970
21.446
0.540
23.894
−0.937
28.601
−1.982
30.851
−3.246
32.984
−4.740
34.943
−6.430
36.756
TABLE XXIII
z = −20 mm
X
Y
−22.214
−26.282
−20.683
−24.942
−19.172
−23.578
−17.670
−22.205
−16.180
−20.819
−14.728
−19.392
−13.353
−17.905
−10.889
−14.728
−8.742
−11.328
−6.831
−7.765
−3.661
−0.323
−2.183
4.174
−1.014
8.742
−0.234
13.401
−0.037
15.773
−0.005
18.144
−0.510
22.827
−1.071
25.139
−1.836
27.393
−3.977
31.617
−4.658
32.603
−5.400
33.542
−7.006
35.315
TABLE XXIV
z = −25 mm
X
Y
−22.961
−27.642
−22.018
−26.664
−21.095
−25.669
−19.289
−23.642
−15.812
−19.472
−12.680
−15.049
−9.911
−10.389
−8.345
−7.520
−6.615
−4.030
−5.102
−0.441
−3.634
3.837
−3.014
6.011
−2.481
8.210
−1.722
12.644
−1.476
17.128
−1.592
19.393
−1.890
21.635
−3.064
25.986
−3.957
28.073
−5.049
30.035
−6.358
31.855
−7.844
33.558
TABLE XXV
z = −30 mm
X
Y
−4.440
6.519
−3.341
13.018
−3.243
16.316
−3.330
17.977
−3.515
19.623
−4.193
22.849
−4.700
24.428
−5.326
25.969
−6.933
28.834
−8.986
31.417
TABLE XXVI
z = −35 mm
X
Y
−5.258
14.085
−5.583
18.053
−5.972
20.003
−6.524
21.926
−8.139
25.532
−9.219
27.183
−10.437
28.755
Both prototype and manufactured surfaces resulting from the application of Tables I-IX and Tables X-XXVI may conform to these points within reasonable process tolerances.
FIG. 5 illustrates an exemplary method 500 for constructing a blade surface according to an embodiment of the present invention. In step 510 , a radius cut is sketched. Points are identified along that radius cut in step 520 and a spline is drafted to connect the aforementioned points in step 530 . In step 540 , each radius cut sketch is lofted in increasing radius order to form a surface. The surface may be extended or trimmed at the edges to reach the exact desired dimensions in step 550 .
FIG. 6 illustrates a method 600 for forming a blade according to an embodiment of the present invention. In step 610 , the surface (as may be created through the method described with respect to FIG. 5 ) is offset by a constant amount. In step 620 , the offset is filled to form a single blade. In optional step 630 , the bluntness of the leading and/or trailing edges may be altered for desired operating conditions.
FIG. 7 illustrates an alternative method 700 for forming a blade according to an embodiment of the present invention. In step 710 , a complimentary airfoil shape is created. In step 720 , a semi- or fully-airfoil blade cross-section is created on one or both sides of the blade. This cross-section may then be lofted into a solid in step 730 . Alterations may also be made with respect to the bluntness of the leading and/or trailing edges for the purpose of desired operating conditions in step 740 .
FIG. 8 illustrates an exemplary method 800 for constructing a fan according to an embodiment of the present invention. In step 810 , blades are oriented with respect to the hub, which may include rotating the in-tact blade surface about an axis to change the pitch, dihedral, or sweep angle as they pertain to desired fan performance. The blade is then patterned around the hub or other fixturing device in step 820 for the appropriate number of blades. Blades can be fully or partially attached to the hub in step 830 and radiused as desired. Alterations may also be made to the leading and/or trailing edge bluntness in order to achieve desired operation conditions.
While Tables I-IX, for example, dictate an 87 mm diameter fan, the blade surface, full blade, and/or final fan may be scaled to change the size and output of the fan as may the measurements set forth in Tables X-XXVI. The resulting fan blade may be mirrored or run in either rotation. Additional attributes may be added to the fan including radii, mid-blade or blade-tip winglets (vertical extrusions out of the blade), full or partial-depth rings, extended or indented turbulators (bumps or cavities along the blade to change boundary layer behavior or noise), embossings, fastening devices, coatings and so forth. Additional surface features and/or strategic roughness may be employed. Furthermore, this blade surface may also be used in a similar fashion to make a non-rotating fan, or stator.
The methods disclosed with respect to FIGS. 5-8 may be embodied in computer software. A computer-readable storage medium may have embodied thereon a program. The program may be executable by a processor to perform the methods or combinations thereof as disclosed herein. These methods may be applicable in the field of computer-aided drafting or design, which may include three-dimensional design tools. The results of such computer-aided drafting and design may be rendered on a display device (e.g., a computer monitor) or printed to a tangible medium such as a computer printout. These results may be annotated with measurement information.
FIGS. 9A-9E illustrate exemplary fans constructed utilizing the surface profile disclosed with respect to FIG. 3 . These fan configurations are exemplary and various elements thereof (e.g., hub, blade number, blade configuration, stators) may be interchangeably combined with one another and in conjunction with a particular surface profile to construct a fan in accordance with an embodiment of the present invention.
FIG. 9A illustrates an exemplary fan including five blades arranged about a cylindrical and hollowed hub.
FIG. 9B illustrates another exemplary fan including seven blades arranged about a cylindrical and capped hub.
FIG. 9C illustrates an exemplary fan including five blades with serrated edges and arranged about a conical hub.
FIG. 9D illustrates an exemplary fan including twelve blades with a notched edge and arranged about a cylindrical and capped hub.
FIG. 9E illustrates an exemplary fan including two blades and arranged about a cylindrical hub, the fan being enclosed within a stator.
FIGS. 10A-10E illustrate exemplary fans constructed utilizing the surface profile disclosed with respect to FIG. 4 . These fan configurations are exemplary and various elements thereof (e.g., hub, blade number, blade configuration, stators) may be interchangeably combined with one another and in conjunction with a particular surface profile to construct a fan in accordance with an embodiment of the present invention.
FIG. 10A illustrates an exemplary fan including three blades extending outward in three-dimensions from an otherwise flat, two-dimensional hub.
FIG. 10B illustrates an exemplary fan including six blades and arranged about a cylindrical and solid hub, the fan being enclosed within a stator.
FIG. 10C illustrates an exemplary fan including three blades extending outward in three-dimensions from a conical hub.
FIG. 10D illustrates an exemplary fan including fourteen blades and arranged about a cylindrical hub, each of the blades being coupled to one another by intermediate ‘webbing.’
FIG. 10E illustrates an exemplary fan including four blades and arranged about a cylindrical and solid hub.
While the present invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements or steps thereof without departing from the true spirit and scope of the present invention. For example, methods of design may be applied to methods of manufacture.
|
A fan or rotor design where the surface profile may be configured to desired dimensions particular to a given operating environment is disclosed.
| 8
|
BACKGROUND OF THE INVENTION
This invention relates to certain novel 2-substituted-4-(chloroacetylamino)methyl-1,3-dioxolanes which are useful as herbicides.
DESCRIPTION OF THE INVENTION
The compounds of this invention have the following structural formula ##STR2## wherein R is:
(A) ALKYL HAVING 1 TO 6 CARBON ATOMS, PREFERABLY 1 TO 4 CARBON ATOMS
(B) HALOALKYL HAVING 1 TO 4 CARBON ATOMS, PREFERABLY 1 TO 2 CARBON ATOMS
(C) VINYL
(D) BENZYL
(E) PHENETHYL
(F) PHENYL
(G) MONO-SUBSTITUTED PHENYL WHEREIN THE SUBSTITUENT IS PHENOXY, BENZYLOXY, HALOGEN, PREFERABLY CHLORINE, ALKYL HAVING 1 TO 4 CARBON ATOMS, PREFERABLY METHYL, ALKOXY HAVING 1 TO 4 CARBON ATOMS, PREFERABLY 1 TO 2 CARBON ATOMS OR NITRO, MOST PREFERABLY HALOGEN OR METHYL
(H) DI-SUBSTITUTED PHENYL WHEREIN THE SUBSTITUTES ARE HALOGEN, PREFERABLY CHLORINE, NITRO OR METHOXY
(I) SUBSTITUTED PHENOXYMETHYL WHEREIN THE SUBSTITUENT IS CHLORINE, NITRO, METHOXY, 3,5-DIMETHYL OR 2,4-DICHLORO OR
(J) ACETYLMETHYL, MOST PREFERABLY R is phenyl or mono-substituted phenyl.
In the above description of the compounds of this invention, alkyl includes both straight chain and branched chain configurations, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl or tert. butyl. The terms halo and halogen include chlorine, bromine, iodine and fluorine.
The compounds of this invention are active herbicides of a general type. That is, they are herbicidally effective against a wide range of plant species. The method of controlling undesired vegetation of the present invention comprises applying a herbicidally effective amount of the above-described compounds to the area where control is desired.
The compounds of the present invention are prepared by the following general method. ##STR3##
Generally, a mole amount of 3-amino-1,2-propanediol dissolved in a solvent such as methanol is added to a solution of methyl chloroacetate in the same solvent at a temperature of about 5°-10° C. Then the reaction mixture is heated for about five hours at 5°-10° C. with stirring. Thereafter, the mixture is cooled and allowed to stand for several days. The solution is evaporated in vacuum to yield the desired product at high yields. ##STR4## R a is methyl or ethyl and R is as previously defined.
Generally, a mole amount of the amide reaction product of Reaction No. 1, a mole amount of the acetal reactant and about 0.2 mole of a strong acid catalyst such as 2-naphthalene-sulfonic acid dihydrate or NH 4 Cl or about 1 mole boron trifluoride etherate are dissolved in a solvent such as dichloroethane or acetonitrile mixed in a reaction vessel fitted with a packed distillation column, for example, a column packed with glass helices. The column is equipped with a variable tape-off distillation head attached to the column. The reaction mixture is heated to reflux with stirring. Initially, methyl or ethyl alcohol is removed as an azeotrope at its boiling temperature around 70°-73° C. for ethanol. When a head temperature reaches the boiling point of the solvent, 83° C., the reaction is complete.
The reaction mixture is then cooled to room temperature and washed with water, two portions of a base such as sodium carbonate solution and finally water. The final aqueous solution is dried over magnesium sulfate and evaporated to yield the desired reaction product.
The acetal reactant, (R a O) 2 CH--R, where R a and R are as defined, can be prepared in situ if desired by reacting either trimethylorthoformate or triethylorthoformate with the appropriately substituted acetaldehyde.
Preparation of the compounds of this invention is illustrated by the following examples.
EXAMPLE I
N-(2,3-dihydroxypropyl) chloroacetamide
This example teaches a method of preparation for the reactant N-(2,3-dihydroxypropyl) chloroacetamide.
A solution of 25 grams (g.) (0.27 mole) of 3-amino-1,2-propanediol in 50 milliliter (ml.) methyl alcohol is added slowly to a solution of methyl chloroacetate, 33.0 g. (0.30 mole) in 50 ml. methyl alcohol at 5°-10° C. The solution is stirred for five hours at 5°-10° C. and is then allowed to stand in the cold for four days. The solution is then evaporated in vacuum to leave 43 g. of the desired product, a viscous oil, n D 30 1.5148. (95% yield).
EXAMPLE II
2-phenyl-4-(chloroacetylamino)methyl-1,3-dioxolane
This example teaches the preparation of a representative compound of this invention.
A mixture of 60 g. (0.04 mole) of N-(2,3-dihydroxypropyl) chloroacetamide, 7.2 g. (0.04 mole) of benzaldehyde diethylacetal and 0.2 g. 2-naphthalene-sulfonic acid dihydrate, ##STR5## in 50 ml. dichloroethane are placed in a 100 ml. flask fitted with a magnetic stirring bar, thermometer and a 10 centimeter (cm.) column packed with glass helices. A variable tape-off distillation head is attached to the column. The reaction mixture is heated to reflux in this apparatus and the formed ethyl alcohol is removed as an azeotrope at a temperature of about 70°-73° C. Distillate is removed until a head temperature of 83° C. is reached to give 7.1 g.
The reaction mixture is then cooled to room temperature and washed with 50 ml. water, two 50 ml. portions of sodium carbonate solution and 50 ml. water. The solution is dried over magnesium sulfate and evaporated to yield the desired product, a liquid 5.8 g. (63% yield), n D 30 1.5428, identified as the title compound by nuclear magnetic resonance spectroscopy.
EXAMPLE III
2-benzyl-4-(chloroacetylamino)methyl-1,3-dioxolane
This example teaches the preparation of a compound of this invention employing boron trifluoride-etherate as a catalyst.
In the apparatus described in Example II is placed 5.0 g. (0.03 mole) phenylacetaldehyde dimethylacetal having the structural formula, ##STR6## 5.0 g. (0.03 mole) N-(2,3-dihydroxypropyl) chloroacetamide, 4.3 g. (0.03 mole) boron trifluoride-etherate (BF 3 .C 2 H 5 OC 2 H 5 ) and 50 ml. acetonitrile. The mixtue is heated at reflux. Initial reflux temperature is 36° C. and distillate is taken until a head temperature of 82° C. is reached. The reaction mixture is then poured into 100 ml. of sodium bicarbonate solution and this mixture is extracted with two 50 ml. portions of methylene chloride. The extracts are combined and washed with 50 ml. water, two 50 ml. portions of sodium bicarbonate solution and 50 ml. water. The solution is dried and evaporated to yield a liquid, 3.6 g. (44.5% yield) n D 30 1.5822, identified by nuclear magnetic resonance spectroscopy as the title compound.
EXAMPLE IV
2-(p-fluorophenyl)-4-chloroacetylamino)methyl 1,3-dioxolane
This example teaches the preparation of a compound of this invention where the acetal reactant is prepared in situ.
In the apparatus described in Example II, 5.0 g. (0.03 mole) N-2,3-dihydroxypropyl chloroacetamide, 3.7 g. (0.03 mole) p-fluorobenzaldehyde, 4.4 g. (0.03 mole) trimethylorthoformate and 0.2 g. of 2-naphthalene sulfonic acid dihydrate are placed. The reaction mixture is allowed to proceed as described in Example II to yield 4.5 g. (55% yield) of a liquid, n D 30 1.5314 identified by nuclear magnetic resonance spectroscopy as the title compound.
The overall reaction equation is as follows: ##STR7##
The following is a table of certain selected compounds that are preparable according to the procedure described hereto. Compound numbers are assigned to each compound and are used through the remainder of the application.
Table 1______________________________________ ##STR8##Compound RNumber R n.sub.D.sup.30______________________________________ 1 CH.sub.3 1.4850 2 (CH.sub.3).sub.2 CH 1.4761 3 CH.sub.2CH 1.4919 4 C.sub.2 H.sub.5 1.4815 5 ClCH.sub.2 1.5000 6.sup.a ##STR9## 1.5428 7 CH.sub.3 CH.sub.2 CH.sub.2 1.4793 8 BrCH.sub.2 dark oil 9 ##STR10## 1.554310 ##STR11## 1.550011 ##STR12## 1.570012 ##STR13## 1.540013 ##STR14## 1.532514 ##STR15## 1.537515 ##STR16## dark oil16 ##STR17## 1.550517.sup.b ##STR18## 1.582218 ##STR19## 1.540019 ##STR20## 1.578420 ##STR21## 1.533521 ##STR22## 1.540022 ##STR23## 1.561223 ##STR24## 1.566424.sup.c ##STR25## 1.531425 ##STR26## 1.540026 ##STR27## 1.534827 ##STR28## 1.557728 ##STR29## 1.561229 ##STR30## 1.572830 ##STR31## 1.542731 ##STR32## 1.542132 ##STR33## 1.534133 ##STR34## 1.559434 ##STR35## 1.5395 .sup.a Prepared in Example II .sup.b Prepared in Example III .sup.c Prepared in Example IV
Herbicidal Screening Tests
As previously mentioned, the herein described compounds produced in the above-described manner are phytotoxic compounds which are useful and valuable in controlling various plant species. Selected compounds of this invention are tested as herbicides in the following manner.
Pre-emergence herbicide test.
On the day preceding treatment, seeds of seven different weed species are planted in individual rows using one species per row across the width of the flat. The seeds used are hairy crabgrass (Digitaris sanguinalis), yellow foxtail (Setaria glauca), watergrass (Echinochloa crusgalli), California red oat (Avena sativa), redroot pigweed (Amaranthus retroflexus), Indian mustard (Brassica juncea) and curly dock (Rumex crispus). Ample seeds are planted to give about 20 to 50 seedlings per row, after emergence, depending upon the size of the plants. The flats are watered after planting. Using an analytical balance, 20 ml. of the compound to be tested was weighed out on a piece of glassine weighing paper. The paper and compound were placed in a 30 ml. wide-mouth bottle and 3 ml. of acetone containing 1% polyoxyethylene sorbitan monolaurate emulsifier was added to dissolve the compound. If the material was not soluble in acetone, another solvent such as water, alcohol or dimethylformamide (DMF) was used instead. When DMF was used, only 0.5 ml. or less was used to dissolve the compound and then another solvent was used to make the volume up to 3 ml. The 3 ml. solution was sprayed uniformly on the soil contained in a small flat 7 inches long, 5 inches wide and 2.75 inches deep, one day after planting weed seeds in the flat of soil. A No. 152 DeVilbiss atomizer was used to apply the spray using compressed air at a pressure of 5 lb/sq. inch. The rate of application was 8 lb/acre and the spray volume was 143 gallon/acre.
After treatment, the flats were placed in the greenhouse at a temperature of 70° to 85° F. and watered by sprinkling. Two weeks after treatment the degree of injury or control was determined by comparison with untreated check plants of the same age. The injury rating from 0 to 100% was recorded for each species as percent control with 0% representing no injury and 100% representing complete control.
Post-emergence herbicide test.
Seeds of six plant species, including hairy crabgrass, watergrass, red oat, mustard, curly dock and pinto beans (Phaseolus vulgaris) were planted in the flats as described above for pre-emergence screening. The flats were placed in the greenhouse at 70° to 85° F. and watered daily with a sprinkler. About 10 to 14 days after planting, when the primary leaves of the bean plants were almost fully expanded and the first trifoliate leaves were just starting to form, the plants were sprayed. The spray was prepared by weighing out 20 ml. of the test compound, dissolving it in 2.5 ml. of acetone containing 1% polyoxyethylene sorbitan monolaurate and then adding 2.5 ml. of water. The solution was sprayed on the foliage using a No. 152 DeVilbiss atomizer at an air pressure of 5 lb/sq. inch. The spray concentration was 0.2% and the rate is 8 lb/acre. The spray volume was 238 gallon/acre.
The injury rating is from 0 to 100% as described above for the pre-emergence herbicide screening test.
The results of these tests are shown in the following Table 2.
Table 2______________________________________ Pre-emergence Post-emergenceCompound Control Control______________________________________1 66 152 52 133 45 324 51 375 46 356 52 437 54 358 47 409 67 4310 24 011 4 012 0 5013 19 2514 39 015 32 316 53 3317 51 3518 48 2319 53 3920 42 021 24 022 47 023 49 2324 62 3325 45 3826 42 327 65 2728 56 1329 39 030 48 5831 70 3932 65 3933 50 4134 45 20______________________________________
The compounds of the present invention are used as pre-emergence or post-emergence herbicides and are applied in a variety of ways at various concentrations. In practice, the compounds herein defined are formulated into herbicidal compositions, by admixture, in herbicidally effective amounts, with the adjuvants and carriers normally employed for facilitating the dispersion of active ingredients for agricultural applications, recognizing the fact that the formulation and mode of application of a toxicant may affect the activity of the materials in a given application. Thus, these active herbicidal compounds may be formulated as granules of relatively large particle size, as wettable powders, as emulsifiable concentrates, as powdery dusts, as solutions or as any of several other known types of formulations, depending upon the desired mode of application. Preferred formulations for both pre- and post-emergence herbicidal applications are wettable powders, emulsifiable concentrates and granules. These formulations may contain as little as about 0.5% to as much as about 95% or more by weight of active ingredient. A herbicidally effective amount depends upon the nature of the seeds or plants to be controlled and the rate of application varies from about 0.05 to approximately 25 pounds per acre, preferably from about 0.1 to 10 pounds per acre.
Wettable powders are in the form of finely divided particles which disperse readily in water or other dispersant. The wettable powder is ultimately applied to the soil either as a dry dust or as a dispersion in water or other liquid. Typical carriers for wettable powders include fuller's earth, kaolin clays, silicas and other readily wet organic or inorganic diluents. Wettable powders normally are prepared to contain about 5% to about 95% of the active ingredient by weight and usually also contain a small amount of wetting, dispersing or emulsifying agent to facilitate wetting and dispersion.
Emulsifiable concentrates are homogeneous liquid compositions which are dispersible in water or other dispersant, and may consist entirely of the active compound with a liquid or solid emulsifying agent, or may also contain a liquid carrier, such as xylene, heavy aromatic naphthal, isophorone and other nonvolatile organic solvents. For herbicidal application, these concentrates are dispersed in water or other liquid carrier and normally applied as a spray to the area to be treated. The percentage by weight of the essential active ingredient may vary according to the manner in which the composition is to be applied, but in general comprises about 0.5% to 95% of active by weight of the herbicidal composition.
Granular formulations, wherein the toxicant is carried on relatively coarse particles, are usually applied without dilution to the area in which suppression of vegetation is desired. Typical carriers for granular formulations include sand, fuller's earth, bentonite clays, vermiculite, perlite and other organic or inorganic materials which absorb or which may be coated with the toxicant. Granular formulations normally are prepared to contain about 5% to about 25% of active ingredient and may also contain small amounts of other ingredients which may include surface-active agents such as wetting agents, dispersing agents or emulsifiers; oils such as heavy aromatic naphthas, kerosene or other petroleum fractions, or vegetable oils; and/or stickers such as dextrins, glue or synthetic resins.
Typical wetting, dispersing or emulsifying agents used in agricultural formulations include, for example, the alkyl and alkylaryl sulfonates and sulfates and their sodium salts; polyhydric alcohols; and other types of surface-active agents, many of which are available in commerce. The surface-active agent, when used, normally comprises from 0.1% to 15% by weight of the herbicidal composition.
Dusts, which are free-flowing admixtures of the active ingredient with finely divided solids such as talc, clays, flours, and other organic and inorganic solids which act as dispersants and carriers for the toxicant, are useful formulations for soil-incorporating applications.
Pastes, which are homogeneous suspensions of a finely divided solid toxicant in a liquid carrier such as water or oil, are employed for specific purposes. These formulations normally contain about 5% to about 95% of active ingredient by weight, and may also contain small amounts of a wetting, dispersing or emulsifying agent to facilitate dispersion. For application, the pastes are normally diluted and applied as a spray to the area to be affected.
Other useful formulations for herbicidal applications include simple solutions of the active ingredient in a dispersant in which it is completely soluble at the desired concentration, such as acetone, alkylated naphthalenes, xylene or other organic solvents. Pressurized sprays, typically aerosols, wherein the active ingredient is dispersed in finely-divided form as a result of vaporization of a low boiling dispersant solvent carrier, such as the Freons, may also be used.
The phytotoxic compositions of this invention are applied to the plants in the conventional manner. Thus, the dust and liquid compositions can be applied to the plant by the use of power-dusters, boom and hand sprayers and spray dusters. The compositions can also be applied from airplanes as a dust or a spray because they are effective in very low dosages. In order to modify or control growth of germinating seeds or emerging seedlings, as a typical example, the dust and liquid compositions are applied to the soil according to convention methods and are distributed in the soil to a depth of at least 1/2 inch below the soil surface. It is not necessary that the phytotoxic compositions be admixed with the soil particles since these compositions can also be applied merely by spraying or sprinkling the surface of the soil. The phytotoxic compositions of this invention can also be applied by addition to irrigation water supplied to the field to be treated. This method of application permits the penetration of the compositions into the soil as the water is absorbed therein. Dust compositions, granular compositions or liquid formulations applied to the surface of the soil can be distributed below the surface of the soil by conventional means such as discing, dragging or mixing operations.
The phytotoxic compositions of this invention can also contain other additaments, for example, fertilizers, pesticides and the like, used as adjuvant or in combination with any of the above-described adjuvants. Other phytotoxic compounds useful in combination with the above-described compounds include, for example 2,4-dichlorophenoxyacetic acids, 2,4,5-trichlorophenoxyacetic acid, 2-methyl-4-chlorophenoxyacetic acid and the salts, esters and amides thereof; triazine derivatives, such as 2,4-bis(3-methoxypropylamino)-6-methylthio-s-triazine, 2-chloro-4-ethylamino-6-isopropylamino-s-triazine, and 2-ethylamino-4-isopropylamino-6-methylmercapto-s-triazine; urea derivatives, such as 3-(3,4-dichlorophenyl)-1,1-dimethyl urea and 3-(p-chlorophenyl)-1,1-dimethyl urea; and acetamides such as N,N-diallyl-α-chloroacetamide, and the like; benzoic acids such as 3-amino-2,5-dichlorobenzoic; thiocarbamates, such as S-propyl dipropylthiocarbamate, S-ethyl-dipropylthiocarbamate, S-ethyl cyclohexylethyl thiocarbamate, S-ethyl hexahydro-1H-azepine-1-carbothioate and the like; 4-(methylsulfonyl)-2,6-dinitro-N,N-substituted anilines, such as 4-(methylsulfonyl)-2,6-dinitro-N,N-substituted anilines, such as 4-trifluoromethyl-2,6-dinitro-N,N-di-n-propyl aniline and 4-trifluoromethyl-2,6-dinitro-N-ethyl-N-n-butyl aniline. Fertilizers useful in combination with the active ingredients include, for example, ammonium nitrate, urea and superphosphate. Other useful additaments include materials in which plant organisms take root and grow such as compost, manure, humus, sand and the like.
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Compounds having the following structural formula ##STR1## wherein R is alkyl, haloalkyl, vinyl, benzyl, phenethyl, phenyl, mono-substituted phenyl, di-substituted phenyl, substituted phenoxymethyl or acetylmethyl which are useful as herbicides.
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FIELD OF THE INVENTION
This invention relates to the preparation of antihalation layers for photographic film. More particularly this invention relates to a process for the preparation of colloidal manganese dioxide adapted for use in antihalation layers.
BACKGROUND OF THE INVENTION
Scattered and reflected incident radiation can expose a radiation sensitive layer in regions in which exposure is not desired. The use of antihalation layers to prevent this unwanted exposure is well known. Typically these auxiliary layers contain a dye or a pigment which absorbs the incident radiation. An antihalation layer may be either a backing layer, positioned on the side of the support opposite that bearing the radiation sensitive layer or layers, or an undercoat layer, located between the support and the radiation sensitive layer or layers.
Although dyes are used in antihalation layers, they frequently cause undesirable residual stain on the processed film. The use of manganese dioxide in antihalation layers is well known. The material possesses desirable absorption characteristics for use in antihalation layers and is cleared in the developing process.
Manganese dioxide containing antihalation layers have been prepared by a number of different processes. Gelatin, alcohols, and polyvinyl alcohol have each been used to reduce potassium permanganate to manganese dioxide. Mackey, U.S. Pat. No. 3,869,401, discloses the preparation of manganese dioxide by reduction of potassium permanganate with polyols. Sato, U.S. Pat. No. 3,773,539, discloses the reduction of potassium permanganate with a chemically modified gelatin obtained by reacting the gelatin with a compound capable of reacting with the amino group of the gelatin, such as sulfonyl chlorides, carboxylic acid chlorides, acid anhydrides, etc. Hine, U.S. Pat. No. 3,630,739, discloses preparation of manganese dioxide by addition of potassium permanganate to an aqueous solution of a hydrolyzed maleic anhydride copolymer, such as a methyl vinyl ether/maleic anhydride copolymer, an ethylene/maleic anhydride copolymer, etc. In this process the polymer hydrolyzate serves as the reducing agent or an auxiliary reducing agent may be added to assist in the reduction of the permanganate salt.
Each of these processes has certain disadvantages. Some are extremely difficult to run on a commercial scale and/or can produce unstable colloids which aggregate producing materials which are unsuitable for use in antihalation layer. Use of gelatin as the dispersing agent causes degradation of the gelatin due to attack of the permanganate on the gelatin. Aldehydes can not be used as reducing agents with gelatin since they would crosslink the gelatin. Other dispersing agents can produce unstable colloids which are not suitable for use in antihalation layers.
To be useful in an antihalation layer, the pigment must be colloidal in size for optical efficiency and must not form aggregates during the preparation process. In addition, the process must not cause degradation of the properties of the layer, especially if the layer is a backing layer containing matte particles so that it can be used for drafting and other applications in which it is desired to write on the backing layer. Current manganese dioxide containing backing layer suffer from this disadvantage, causing pen clogging, pencil gouging, etc.
SUMMARY OF THE INVENTION
In accordance with this invention there is provided in a process for the preparation of colloidal manganese dioxide dispersions adapted for use in antihalation layers, the process comprising adding a reducing agent to an aqueous solution comprising a water soluble permanganate salt and a dispersing agent,
the improvement wherein said dispersing agent is a water soluble polymer selected from the group consisting of water soluble carboxylated acrylic polymers, water soluble styrene/acrylic copolymers, and water soluble alpha-methyl styrene/acrylic copolymers.
DETAILED DESCRIPTION OF THE INVENTION
Manganse Dioxide Dispersion
Colloidal manganese dioxide dispersions may be prepared by the reduction of an aqueous solution of a water soluble permanganate salt with a reducing agent in the presence of a dispersing agent. Outstanding dispersing agents are water soluble carboxylated acrylic polymers, water soluble styrene/acrylic copolymers, and water soluble alpha-methyl styrene/acrylic copolymers. The resultant colloidal dispersion is compatible with gelatin so that a smooth antihalation layer can be formed on the film base by conventional procedures.
Carboxylated acrylic polymers are polymers which comprise acrylic acid and/or methacrylic acid copolymerized with other monomers, especially other acrylic monomers, such as, for example, methyl acrylate, methyl methacrylate, and ethyl acrylate. Styrene/acrylic copolymers are copolymers which comprise acrylic acid and/or methacrylic acid copolymerized with styrene. alpha-Methyl styrene/acrylic copolymers are copolymers which comprise acrylic acid and/or methacrylic acid copolymerized with alpha-methyl styrene. The copolymer must comprise a sufficient level of copolymerized acrylic acid and/or methacrylic acid that it is water soluble. The dispersing agent must be sufficiently water soluble that a stable dispersion of manganese dioxide can be prepared.
The general method for preparing manganese oxide dispersions is to add a reducing agent to a stirred aqueous solution of a water soluble permanganate salt and the water soluble dispersing agent. The reducing agent is normally added as an aqueous solution. Addition as in aqueous suspension may be used if the reducing agent is not soluble in water. Although it is generally more convenient to add the reducing agent to the solution of permanganate salt and dispersing agent, addition of a solution of the permanganate salt to an aqueous solution or suspension of reducing agent and dispersing agent may also be carried out. Stirring should be adequate to provide good mixing.
The temperature of addition is not extremely critical. Addition is conveniently carried out at about room temperature, although higher temperatures may be used, if desired. It is not necessary to closely control the temperature of the dispersion during addition of the reducing agent. If desired, the dispersion may be neutralized following addition of the reducing agent. In general, however, it is not necessary to neutralize the dispersion following addition of the reducing agent.
The concentration of dispersing agent is not extremely critical. Good results have been obtained with concentrations in the range of about 4% to about 9% by weight dispersing agent. A convenient concentration is about 6% to 7% by weight dispersing agent. A convenient concentration for the permanganate salt is about 0.2 mol/L to about 0.3 mol/L. The preferred water soluble permanganate salt is potassium permanganate (KMnO 4 ).
Reducing agents which can be used in the practice of this invention include alcohols, such as, for example, methanol and ethanol, and aldehydes, such as for example, formaldehyde, glyoxal, butyraldehyde, and salicylaldehyde. Other reducing agents which may be used to advantage can be determined by reference to redox potentials and routine experimentation. As will be apparent to those skilled in the art, sufficient reducing agent should be added to convert all the permanganate to manganese dioxide.
Aldehydes are a preferred class of reducing agents. Since aldehydes crosslink gelatin, they can not normally be used as the reducing agent in prior art processes in which gelatin is the dispersing agent. More preferred reducing agents are formaldehyde and glyoxal. The most preferred reducing agent is formaldehyde.
Antihalation Layers
Antihalation layers for photosensitive elements may be prepared from the manganese dioxide dispersions by, for example, combining the dispersion with a film-forming binder to provide a coating liquid, and coating the coating liquid onto an appropriate photographic support. Such binders are well-know in the art and include hydrophilic colloids, such as, for example, gelatin, which may be derived from various sources, such as, for example, cattle bone, pigskin, etc.; gelatin derivatives, such as, for example, phthalated gelatin, acetylated gelatin, etc.; polysaccharides, such as, for example, dextran, etc.; synthetic polymers, such as, for example, poly(vinyl alcohol) and water soluble partially hydrolyzed poly(vinyl acetate); acrylamide polymers; polymers of alkyl and sulfoalkyl acrylates and methacrylates; polyamines; poly(vinyl acetals), such as, for example, polyvinyl acetal, etc.; poly(vinyl ethers); etc. Gelatin is preferred as a film-forming binder.
Wetting agents and hardeners, such as are well known in the art, may be added to the antihalation layer. If the antihalation layer is a backing layer for a film, such as a drafting film, that will be drawn or written upon in normal usage, matte may also be added as known to one skilled in the art. For antihalation layers, an optical density of about 0.15 to about 0.35 in the wavelength range used for imaging is desirable.
Photosensitive Layer/Film Support
The photosensitive element comprises a photosensitive layer and a support. The element may also comprise any of a number of the other layers which are conventional in photosensitive elements.
The preparation of silver halide emulsions is well known in the art. Silver halide emulsions, their preparation, and the preparation of photosensitive layers therefrom, are described in, for example: Research Disclosure, Item 17643, December, 1978; Research Disclosure, Item 18431, August, 1979; Research Disclosure, Item 22534, January, 1983; and Abbott, U.S. No. Pat. 4,425,426.
The photosensitive layer is preferably a standard, gelatino silver halide emulsion layer which is applied on one side of the element. Conventional photographic silver halide emulsions employing any of the commonly known halides, such as silver chlorine, silver bromide, silver iodide, and mixtures thereof, may be used. These may be of varied content and may be negative and/or positive working.
The photosensitive layer also comprises a binder. Such binders are well-known in the art and include the materials useful as binders for the antihalation layer, described above. A preferred binder is gelatin.
The photosensitive layer may be hardened by addition of a conventional hardening agent, such as, for example, an aldehyde, such as formaldehyde or glyoxal. Conventional additives may also be present for specific purposes, such as, for example, to aid coating, to enhance and/or stabilize the response of the emulsion, etc.
The support can be any of a number of supports for photosensitive elements known in the art. These include polymeric films such as, for example: cellulose esters, such as, for example, cellulose triacetate, etc.; polyesters of dibasic aromatic carboxylic acids and divalent alcohols, such as, for example, poly(ethylene terephthalate), poly(ethylene isophthalate), etc., paper; polymer coated paper; copolymerized vinyl compounds, such as, for example, vinyl acetate/vinyl chloride copolymer; polystyrene; polyacrylates; etc. Dyes may be incorporated into the support to impart a color thereto.
Preferred supports include polyesters made according to Alles, U.S. Pat. No. 2,779,684, the pertinent disclosure of which is incorporated herein by reference. These supports are particularly suitable because of their dimensional stability. Photographic grade polyethylene terephthalate film, made according to the well-known teachings of the art, is the most preferred film support. The film is cast and then stretched in both dimensions and heat relaxed to attain dimensional stability. A standard resin sub layer is applied on at least one side of the film support to form a thin, anchoring substratum over which a gelatin sublayer may be applied. Typical resin subbing layers include copolymers of vinylidene chloride, such as are disclosed, for example, by Rawlins, U.S. Pat. No. 3,567,452, and Alles, U.S. Pat. No. 2,627,088. The pertinent disclosures of these patents are incorporated herein by reference.
The element may comprise any of a number of the other conventional additives and layers, such as those disclosed in any of the references cited above. These include, for example, optical brighteners, antifoggants, emulsion stabilizers, image stabilizers, filter dyes, intergrain absorbers, light-scattering materials, gelatin hardeners, coating aids, surfactants, overcoat layers, interlayer and barrier layers, antistat layers, plasticizers and lubricants, matting agents, development inhibitor-releasing compounds, etc. The element can be prepared by coating the layers onto the support using coating techniques which are conventional in the art.
Industrial Applicability
Colloidal manganese dioxide dispersions, prepared by the improved processes of this invention, can be used in antihalation layers for photosensitive elements. These dispersions are particularly useful in the production of matte containing backing layers. These photosensitive elements are especially useful for drafting applications.
The advantageous properties of this invention can be observed by reference to the following examples which illustrate, but do not limit, the invention. The percentages in the examples are by weight.
EXAMPLES
______________________________________GLOSSARY______________________________________Glascol RP2 Carboxylated acrylic polymer; Tg 58° C.; 30% solids in water ammonia; pH 7.5; Allied Colloids, Suffolk, VAJoncryl ® 61 Styrene/acrylic copolymer, 34% solids; S. C. Johnson and Son, Racine, WIJoncryl ® 62 Acrylic acid/alpha-methyl styrene copolymer, 30% solids; CAS 26745-16-4; S. C. Johnson and Son, Racine, WILucidene ® 432 Acrylic emulsion; Morton Thiokol, Chicago, ILMorcryl ™ 134 Styrene/acrylic copolymer; Morton Thiokol, Chicago, ILNacrylic ® 78-6178 Carboxylated acrylic polymer; National Starch and Chemical, Bridgewater, NJPFAZ ® 322 1,1,1-Trimethylolpropane tris(2- methyl-1-aziridine propionate; CAS 64265-57-2; Sybron Chemical, Birmingham, NJTiPure ® LW Titanium dioxide nitrile white pigment; E. I. du Pont de Nemours and Company, Wilmington, DESyloid ® 72 Silica matte; Davidson Chemical Company, Cincinnati, OHPolystep ® B-27 14.9% aqueous solution of sodium lauryl ether sulfate; Stephan Chemical Company, Northfield, ILProduct BCO Wetting agent; CAS 69898-09-5; E. I. du Pont de Nemours and Company, Wilmington, DE______________________________________
EXAMPLE 1
This examples demonstrates the preparation of a manganese dioxide dispersion using a carboxylated acrylic polymer dispersing agent.
Step 1. A solution containing 6.42% of carboxylated acrylic polymer in water was prepared by adding 102.5 g of Glascol RP2 (30.75 g of polymer) to 376 g of water. Formaldehyde (22 mL of 6.67 M formaldehyde solution diluted to 50 mL with water) was added. Aqueous potassium permanganate (273 ml of a 0.27 M solution) was pumped in at room temperature at a rate of 26 mL/minute. The solution was stirred during addition. Following addition the temperature of the resulting MnO 2 dispersion was 33° C. and the pH was about 6.8.
Step 2. Water (160 mL) was added to 200 mL of the manganese dioxide dispersion prepared. Dry gelatin (23 g of Kind and Knox gel blend 693) was added. After 15 minutes of stirring at room temperature, the dispersion was heated about 125° F. (about 52° C.) for 15 minutes to dissolve the gelatin. After the gelatin had dissolved, heating was discontinued and the following was added: 3 mL of a dispersion containing 0.6 g of TiPure® LW and 0.03 mL of a 10% sodium hexametaphosphate solution; 29 g of a dispersion containing 16.8% Syloid® 72 and 5% Product BCO; 9 mL of a solution containing 15% Polystep® B27; and 2 mL of Teflon® 30 fluoropolymer resin dispersion.
Step 3. To 100 mL of this dispersion was added 0.75 mL of 0.066 M chromium potassium sulfate solution followed by 1.5 mL of 1.33 M formaldehyde. The dispersion was coated with a Consler #20 rod onto a conventional resin subbed polyethylene terephthalate photographic support.
The optical density of the resulting coated support was measured by a MacBeth TD927 optical transmission densitometer with "white light", "blue light", "green light", and "red light" filters using air as a reference. For comparison, a support containing a conventional manganese dioxide layer made by precipitation in gelatin was also measured. The results are given in Table 1.
TABLE 1______________________________________Optical Density Glascol RP2 Gelatin.sup.a______________________________________White light 0.35 0.31Blue light 0.47 0.43Green light 0.29 0.26Red light 0.21 0.19______________________________________ .sup.a Control
EXAMPLE 2
This example illustrates the preparation of a manganese dioxide dispersion using different concentrations of carboxylated acrylic polymer dispersing agent.
The procedure of Example 1 was repeated except that the dispersing agent was Nacrylic® 78-6178. Three concentrations of dispersing agent were used: 4.24%, 6.42%; and 8.54%. The results are given in Table 2.
TABLE 2______________________________________Optical Density 4.24%.sup.a 6.42% 8.54%______________________________________White light 0.24 0.24 0.24Blue light 0.33 0.33 0.35Green light 0.19 0.19 0.20Red light 0.14 0.13 0.14______________________________________ .sup.a Percentage of Nacrylic ® 786178 dispersing agent present durin preparation of the MnO.sub.2 dispersion.
EXAMPLE 3
This example illustrates the preparation of a manganese dioxide dispersion using a different order of reagent addition.
Step 1 of Example 1 was repeated except that (1) Nacrylic® 78-6178 (6.42%) was used as the dispersing agent and (2) the permanganate solution was added before the formaldehyde solution. A stable dispersion with no aggregates was formed. An aliquot (0.5 mL) was diluted to 200 mL and the absorption spectrum of the resulting dispersion determined. The dispersion had an optical density of 2.37 at 300 nm; 1.90 at 350 nm; and 1.26 at 400 nm. A dispersion prepared by the same procedure except that the formaldehyde was added first has an optical density of 2.57 at 300 nm; 2.15 at 350 nm; and 1.26 at 400 nm.
EXAMPLE 4
This example illustrates the preparation of a manganese dioxide dispersion with different dispersing agents and at an elevated temperature.
The procedure of Example 1 was repeated except that (1) Morcryl™ 134 (6.42%) and Joncryl® 61 (6.42%) were each used as the dispersing agent and (2) addition of the formaldehyde was carried out at 48° C. The optical densities of the resulting coated supports are given in Table 3.
TABLE 3______________________________________Optical Density Morcryl ™ 134 Joncryl ® 61______________________________________White light 0.31 0.22Blue light 0.45 0.39Green light 0.25 0.16Red light 0.17 0.09______________________________________
EXAMPLE 5
This example illustrates the preparation of a manganese dioxide dispersion using an alcohol as the reducing agent.
The procedure of Step 1 of Example 1 was repeated except that (1) Nacrylic® 78-6178 (6.42%) was used as the dispersing agent and (2) ethanol (16.6 g diluted to 50 mL with water) was added at 46° C. A stable dispersion with no aggregates was formed. An aliquot (0.5 mL) was diluted to 200 mL and the absorption spectrum of the resulting dispersion determined. The dispersion had an optical density of 1.02 at 300 nm and 0.94 at 400 nm.
EXAMPLE 6
This example illustrates the preparation of a manganese dioxide dispersion using salicylaldehyde as the reducing agent.
The procedure of Step 1 of Example 1 was repeated except that (1) Nacrylic® 78-6178 (6.42%) was used as the dispersing agent and (2) salicylaldehyde (18 g shaken with 32 mL of water) was added at room temperature. A stable dispersion with no aggregates was formed.
EXAMPLE 7
This example illustrates the preparation of manganese dioxide dispersions using glyoxal as the reducing agent and using (1) a carboxylated acrylic polymer and (2) a styrene/acrylic copolymer as dispersing agents.
The procedure of Example 1 was repeated except that (1) Nacrylic™ 78-0178 (6.42%) and Morcryl™ 134 (6.42%) were each used as the dispersing agent and (2) glyoxal (4 mL diluted to 50 mL with water) was added at room temperature. The optical densities of the resulting coated supports are given in Table 4.
TABLE 4______________________________________Optical Density Nacrylic ® 78-0178 Morcryl ™ 134______________________________________White light 0.14 0.25Blue light 0.14 0.34Green light 0.12 0.21Red light 0.11 0.15______________________________________
EXAMPLE 8
This example illustrates the preparation of manganese dioxide dispersions using (1) a carboxylated acrylic polymer and (2) an alpha-methyl styrene/acrylic copolymer as dispersing agents.
The procedure of Example 1 was repeated except that (1) Joncryl® 62 (6.42%) and Nacrylic® 78-6178 (6.42%) were each used as the dispersing agent; (2) the formaldehyde was added at 47° C.; and the dispersion was coated with a Consler #10 rod. The optical densities of the resulting coated supports are given in Table 5.
TABLE 5______________________________________Optical Density Nacrylic ® 78-6178 Joncryl ® 62______________________________________White light 0.19 0.22Blue light 0.28 0.36Green light 0.13 0.16Red light 0.08 0.09______________________________________
COMPARATIVE EXAMPLE
The procedure of Example 1 was repeated except that (1) Lucidene® 432 (6.42%) was used as the dispersing agent and the formaldehyde was added at 47° C. A stable dispersion was not formed. The manganese dioxide aggregated before addition of the formaldehyde was complete.
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This invention relates to the preparation of antihalation layers for photographic film. The invention is an improved process for the preparation of colloidal manganese dioxide dispersions adapted for use in antihalation layers, the process comprising adding a reducing agent to an aqueous solution comprising a water soluble permanganate salt and a dispersing agent, the improvement wherein said dispersing agent is a water soluble polymer selected from the group consisting of water soluble carboxylated acrylic polymers, water soluble styrene/acrylic copolymers, and water soluble alpha-methyl styrene/acrylic copolymers.
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[0001] The invention relates to automatic pool cleaners of the type described by Australian Patents 490972 and 505209, both of which are included herein by reference. In particular, the invention relates to arrangements and methods of operation, which may be implemented so as to reduce the size of an automatic pool cleaner without detrimentally affecting functionality.
[0002] Pool cleaners of the type described above substantially comprise a seal arrangement, sealing a pool surface to a suction zone in fluid communication with a valve chamber. Exiting from said valve chamber are two parallel tubes/passages meeting at a flow attenuation element, which is then connected to a flexible hose. Within said valve chamber there exists a flap valve oscillating between the outlet to each of the tubes. As water flows into the valve chamber, water is drawn up one tube/passage, the mass flow of said water drawing the flap valve over the exit closing off the first tube and creating a water hammer impulse due to the rapid closure. Water is then diverted to the second tube/passage, again drawing the flap valve towards the exit leading to the second tube/passage and, consequently, closing the second tube and diverting water to the first. Therefore, the flap valve oscillates from the first tube/passage to the second tube/passage creating a series of water hammer impulses, which drive the pool cleaner across the pool floor and walls.
[0003] In order to create the desired oscillation frequency and momentum driving the pool cleaner, it has been found that a certain length of tube is desirable. However, for certain applications, and for general economic reasons, it is sometimes desirable to have a pool cleaner with tubes significantly shorter. Because of the complexity of the system, a shortening of the tubes or reduction in internal diameter (ID) does not necessarily equate to an equivalent reduction in size of other components nor the efficiency or effectiveness of the pool cleaner operation due to, inter alia, the reduced mass flow of water oscillating in each tube.
[0004] One problem associated with the use of shorter machines or smaller ID tubes is that of initiating oscillation of the flap valve. It has been found that with a shorter machine instead of the total flow diverting from one tube to the next, the flow is evenly divided between the two tubes/passages. Consequently, the valve fails to start or merely fibrillates in a central position and not thus reaching the extreme positions required to set the pool cleaner in motion. It has been found that the flap valve will oscillate as desired but that operator intervention is required in order to initiate the action.
[0005] It is therefore an object of the invention to automatically initiate the flap valve oscillation on activation of the pool cleaner without an operator having to manually commence the action.
[0006] Therefore, in one aspect of the invention, there is provided a pool cleaner, including a valve chamber having an inlet and two outlet orifices, a valve within the valve chamber adapted to continuously oscillate between a first and a second position due to a water flow through the chamber from the inlet to the outlet orifices and a biassing means adapted to apply an eccentric influence on the valve wherein at initiation of the water flow the biassed means influences the valve towards the first position so as to commence the oscillation.
[0007] An equal division of water flow between the two tubes results in a balance of forces which maintains the flap valve in a central position where it remains stationary or fibrillates.
[0008] The eccentric influence of the present invention provides for a means to turn the symmetrical system into an asymmetrical system by the inclusion of the biassed means. As the water flow enters the valve chamber, the valve will be biassed to one side or the other and thus creates an asymmetrical system initiating the oscillatory action. In any event, the flap must be held away from an extreme position which may close either of the tube/passage apertures.
[0009] Initiation is therefore defined as the commencement of the desired full stroke movement of the flap valve leading to a continuous oscillation. It follows that a differential flow between the tubes will provide an out-of-balance force to the flap valve favouring the tube having the greatest flow. Thus, by applying an imbalance of forces to the valve, the valve will be biassed to one side until it closes off the tube having the least initial flow and permitting a greater flow through the second tube. As a consequence, the valve will be biassed towards the second tube and so the oscillatory action commences.
[0010] Preferably, the biassed means may be an elastic resilient member holding the valve in place and thus its stiffness constant is sufficient to hold the valve whilst not in use but following the commencement of the water flow is insignificant compared to the forces applied to the valve through the change in water flow between the tubes. More preferably, the elastic resilient member may be a rubber member contacting a selected point of the flap valve.
[0011] More preferably, the elastic resilient member may have its primary line of force parallel to the plane transcribed by the movement of the flap valve. Thus, as the resilient member has a contact or connection to the valve chamber aperture wall and the flap valve itself, the connection to the flap valve may be at a central point on an extreme fibre of the valve which traces the peripheral edge of the oscillatory path. In so doing, the resilient member may remain co-linear and resist the forces applied to the flap valve in a purely axial manner. Alternatively, the elastic resilient member may have a line of force substantially orthogonal to the plane transcribed by the oscillatory action.
[0012] Preferably, the biassed means includes a hole or a void in the body of the flap valve placed away from a symmetrical axis of the flap valve. By placing a void offset from a symmetrical axis of the valve, the self weight of the flap valve may act as the biassed means with the void Inclusion providing the eccentric influence. It follows that the larger the void, the greater the out-of-balance forces will be.
[0013] Preferably, the biassed means may be an element located within the flap valve and having a density greater than that of the parent material of the flap valve, said element being located offset from a centre line of the flap valve. In this embodiment, a weighted element may be placed to one side and thus the eccentric influence provided by the weight will be sufficient to provide the imbalance of forces so as to initiate the oscillatory action or reduce the frequency of oscillation.
[0014] Preferably, the biassed means will be at least one relatively stiff member projecting from an internal wall of the valve chamber and in abutting contact with the valve such that the rigidity of the member may be sufficient to hold the flap valve away from an equidistant position between the first and second positions but said stiffness of the elastic member may be insufficient to overcome the forces involved with the oscillatory action and associated mass flow of water.
[0015] The projecting member may be integrally attached to the flap valve. In this case, the projecting member has an integral connection with the flap valve and, thus, on each oscillation the flap valve flexes the projecting member and imparting a flexural and tensile force to said member. Alternatively, the biassed means may include a relatively stiff but elastic projecting member and a corresponding recess in the flap valve such that the member fits within the recess providing an interference for the flap valve to move in an oscillatory motion, said projecting member being of insufficient stiffness to overcome the forces involved with the oscillatory motion of the flap valve.
[0016] Alternatively, the projecting member may be integral with the flap valve and adapted to contact the internal walls of the valve chamber. In this embodiment, the projecting member may be a relatively stiff projection that serves as a stop when contacting the walls of the valve chamber. Alternatively, the projecting member may be elastically resilient so that prior to initiation the flap valve is held in a desired position and following initiation the stiffness of the resilient projecting members is insubstantial compared to the forces during the oscillatory action.
[0017] Preferably, the valve may further include a projection adapted to engage the chamber wall wherein oscillation of the valve occurs through pivoting about said projection. In conventional automatic pool cleaners of this variety, the valve is free to move within the chamber with the chamber shaped so as to guide the valve through a path promoting oscillation. In some circumstances, it may be beneficial for the valve to be connected to the valve chamber using a projection that acts as a pivot. This has a number of advantages including the control of the oscillation frequency and control of the oscillation path.
[0018] More preferably, the pivot projection may be dimensioned or placed so as to impart an eccentric influence upon the valve and so form part of the biassing means. In one preferred embodiment, the projection may be offset from a centre line of the valve. Alternatively, the projection may be non co-linear with a centre line of the valve and the axis of the projection to be skewed to said centre line. In both cases, as water flow commences, there will be an eccentric influence on the motion of the valve, said motion being under the control of the pivoting projection.
[0019] Preferably, the biassed means may be designed so as to control the frequency of the oscillatory action. In all the preceding embodiments of the invention comprising the biassed means, the stiffness of the biassed means has been considered to be insufficient to affect the motion of the flap valve following initiation. If, however, the biassed means can have its stiffness increased, then the higher the stiffness of the biassed means, the lower the frequency of the oscillatory action of flap valve.
[0020] Preferably, the orifice may be located in a demountable orifice plate. For convenient construction of the pool cleaner and to provide access to those elements located within the valve chamber, it may be beneficial to have a portion demountable from the valve chamber. In one embodiment of this convenient demountability of the valve chamber, an orifice plate may provide a convenient means to provide this access, particularly as such a plate may be located on a lower face of the pool cleaner.
[0021] In another aspect of the invention, there is provided a method of initiating the oscillatory motion of a flap valve of an automatic pool cleaner having a first and second tube exiting from a valve chamber, said valve chamber having an inlet orifice and the flap valve adapted to continuously oscillate within the valve chamber between a first and second position due to water flowing through the orifice and the chamber and into the tubes following initiation such that, when in the first position, water entering the inlet orifice is directed into the second tube and, when in the second position, water is directed into the first tube, the steps of the method including biassed the flap valve with a biassed means and drawing the water flow through the orifice and into the valve chamber so that there is a differential flow through the first and second tubes.
DESCRIPTION OF PREFERRED EMBODIMENT
[0022] It will be convenient to further described the present invention with respect to the accompanying drawings, which illustrate a possible arrangement of the invention. Other arrangements of the invention are possible and, consequently, the particularity of the accompanying drawings is not to b understood as superseding the generality of the preceding description of the invention.
[0023] [0023]FIG. 1 is an elevation view of the automatic pool cleaner according to the present invention.
[0024] [0024]FIG. 2 is a close-up elevation view of the valve chamber of the automatic pool cleaner of FIG. 1.
[0025] [0025]FIG. 3 is a close-up elevation view of the valve chamber according to a second aspect of the present invention.
[0026] [0026]FIG. 1 shows an automatic pool cleaner 1 substantially as described in Australian Patent Nos. 490972 and 505209. In particular, the automatic pool cleaner 1 shows parallel tubes 5 and 6 projecting from, and in fluid communication with, a valve chamber 4 in which is located a flap valve 7 . The automatic pool cleaner 1 further includes a sealing arrangement 2 into which is drawn a flow of water, which passes through orifice 3 into the valve chamber 4 . Water is then directed into one of the tubes 5 or 6 as determined by the position of the flap valve 7 at any particular stage. Flap valve 7 is adapted to move within the valve chamber 4 in a single degree of freedom as shown in FIG. 2.
[0027] As shown in the close-up view of the valve chamber 4 in FIG. 2, the flap valve 7 pivots about point 7 a in an arcuate fashion 9 such that at its extreme points of travel, the flap valve 7 will close off either of the apertures 5 a or- 6 a . As the water flow 12 travels up tube 5 , the mass flow of water will tend to deflect the flap valve 7 towards aperture 6 a until it is eventually blocked. This will then direct a greater water flow through aperture 5 a and into tube 5 and, consequently, draw the flap valve back towards the aperture 5 a until it is closed off. The motion of the flap valve 7 continues in the oscillatory manner 9 whilst water is drawn up through the automatic pool cleaner 1 .
[0028] The automatic pool cleaner 1 of FIG. 1 being of conventional size and orientation has tubes 5 and 6 of standard length each having the capacity of holding a substantial volume of water. The mass flow of the water in each of these tubes represents a significant force and so on commencement of the operation of the automatic pool cleaner 1 , the flap valve initiates movement immediately. However, because certain applications require a considerably smaller machine and, therefore, tubes/passages 5 and 6 being considerably shorter or of smaller ID, the mass flow of water through said tubes 5 and 6 will be less and so the applied forces to the flap valve 7 may not initiate the oscillatory action 9 without the intervention of an operator.
[0029] The present invention provides means to initiate the oscillatory action 9 by ensuring a differential force is applied to the flap valve 7 . In the preferred embodiment shown in FIG. 2, the means to provide the imbalance of forces is provided through an elastic resilient member 8 connecting the walls of the valve chamber 4 to an extreme point 7 b of the flap valve 7 . The resilient member 8 , prior to operation of the automatic pool cleaner 1 , positions the flap valve 7 such that its centre line 11 is offset from the centre line of the valve chamber 10 and, thus, creating an asymmetrical system. As problems with initiation of the oscillatory action 9 involve the water flow 12 being equally divided between tubes 5 and 6 and, thus, holding the flap valve 7 in a central position 10 , the preferred embodiment of FIG. 2 solves this problem of symmetrical forces being in balance by creating an offset effect and, thus, permitting a greater flow 12 into tube 5 . Thus, the imbalance of forces applied to the flap valve 7 will naturally deflect the flap valve 7 towards aperture 6 a and, thus, initiating the oscillatory action 9 .
[0030] Importantly, the elastic resilient member 8 must have a stiffness constant such that, prior to initiation, the flap valve 7 is held in the desired location but following initiation has insufficient stiffness to hinder the oscillatory action 9 .
[0031] [0031]FIG. 3 shows a second aspect of the present invention applied to an alternate constructional arrangement. In this arrangement, the flap valve 7 has a direct connection to the chamber whereby a projection 13 from the flap valve 7 is in a press fit engagement with a portion 14 of the chamber. Whilst in motion 9 , the flap valve 7 oscillates in a pivotal manner about the connection between the projection 13 and the engagement portion 14 . This constructional arrangement is advantageous in providing a further means of biassing the flap valve. In this embodiment, the placement of the projection 13 is such that the axis 16 of the projection 13 is not co-linear with the centre line 11 of the flap valve 7 . The misalignment of the axis 16 and centre line 11 represents a lack of symmetry about the centre line 11 and consequently the movement of the flap valve 7 will be influenced in a direction opposed from the offset represented by the axis 16 and centre line 11 .
[0032] In another preferred embodiment, the flap valve 7 may further include flexural springs 17 , being portions projecting away from the flap valve 7 , which are arranged such that when a leading portion 18 contacts a wall of the chamber 19 , spring energy is developed within the projections 17 biassing the valve 7 in the opposite direction. Where the projections 17 are identical and placed symmetrically about the centre line 11 , said projections will act together in oscillating the valve. When said projections 17 are used with an offset projection 13 about which the valve 7 pivots, the asymmetric alignment of the pivoting motion is such that the projections 17 will not act in an identical manner and will therefore assist in the influencing of the valve 7 and form part of the biassing means.
[0033] Various embodiments of the present invention are herein described with further possible variance described without reference to drawings. It will be appreciated by the person skilled in the art that any of the preferred arrangements of the biassing means and, in fact, various combinations may be incorporated so as to fall within the scope of the present invention. Further, other embodiments may be apparent to the person skilled in the art so as to achieve the result of the present invention and would fall within the scope of the invention as described.
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A pool cleaner, including a valve chamber ( 4 ) having an inlet and two outlet orifices and a valve ( 7 ) within the valve chamber. The valve continuously oscillates between first and second positions due to water flow through the chamber from the inlet to the outlet orifices. A bias means ( 8 ), in the form of resilient projections on the valve ( 17 ), the valve being offset in the chamber or a stiff projection from the valve ( 13 ) contacting the wall of the valve chamber. The bias means applies an eccentric influence on the valve such that the operator does not need to initiate oscillation of the valve.
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RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application Ser. No. 60/840,170 filed Aug. 25, 2006 and U.S. Provisional Application Ser. No. 60/814,437, filed Jun. 16, 2006. The entire contents of both of the above applications is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to an implant having high resistance to fracture when mechanically cycled at a site in a body lumen. More particularly, this invention pertains to a fatigue fracture resistant vascular implant such as a self-expanding stent.
BACKGROUND OF THE INVENTION
[0003] Stents are widely used for supporting a lumen structure in a patient's body. For example, stents may be used to maintain patency of a coronary artery, carotid artery, cerebral artery, popliteal artery, iliac artery, femoral artery, tibial artery, other blood vessels including veins, or other body lumens such as the ureter, urethra, bronchus, esophagus, or other passage.
[0004] Stents are commonly metallic tubular structures made from stainless steel, Nitinol, Elgiloy, cobalt chrome alloys, tantalum, and other metals, although polymer stents are known. Stents can be permanent enduring implants, or can be bioabsorbable at least in part. Bioabsorbable stents can be polymeric, bio-polymeric, ceramic, bio-ceramic, or metallic, and may elute over time substances such as drugs. Non-bioabsorbable stents may also release drugs over time. Stents are passed through a body lumen in a collapsed state. At the point of an obstruction or other deployment site in the body lumen, the stent is expanded to an expanded diameter to support the lumen at the deployment site.
[0005] In certain designs, stents are open-celled or close-celled cylindrical structures that are expanded by inflatable balloons at the deployment site. This type of stent is often referred to as a “balloon expandable” stent. Stent delivery systems for balloon expandable stents are typically comprised of an inflatable balloon mounted on a multi lumen tube. The stent delivery system with stent crimped thereon can be advanced to a treatment site over a guidewire, and the balloon inflated to expand and deploy the stent.
[0006] Other stents are so-called “self expanding” stents and do not use balloons to cause the expansion of the stent. An example of a self-expanding stent is a tube (e.g., a coil tube, a mesh tube, or an open-celled tube) made of an elastically deformable material (e.g., a superelastic material such a nitinol). This type of stent is secured to a stent delivery device under tension in a collapsed state. At the deployment site, the stent is released so that internal tension within the stent causes the stent to self-expand to its enlarged diameter.
[0007] Other self-expanding stents are made of so-called shape-memory metals. Such shape-memory stents experience a phase change at the elevated temperature of the human body. The phase change results in expansion from a collapsed state to an enlarged state.
[0008] A very popular type of self expanding stent is an open-celled tube made from superelastic nitinol, for example, the Protégé GPS stent from ev3, Inc. of Plymouth, Minn. Open or closed cell tube stents are commonly made by laser cutting of tubes, or cutting patterns into sheets followed by or preceded by welding the sheet into a tube shape, and other methods. Another delivery technique for a self expanding stent is to mount the collapsed stent on a distal end of a stent delivery system. Such a system can be comprised of an outer tubular member and an inner tubular member. The inner and outer tubular members are axially slideable relative to one another. The stent (in the collapsed state) is mounted surrounding the inner tubular member at its distal end. The outer tubular member (also called the outer sheath) surrounds the stent at the distal end.
[0009] Prior to advancing the stent delivery system through the body lumen, a guide wire is first passed through the body lumen to the deployment site. The inner tube of the delivery system is hollow throughout at least a portion of its length such that it can be advanced over the guide wire to the deployment site. The combined structure (i.e., stent mounted on stent delivery system) is passed through the patient's lumen until the distal end of the delivery system arrives at the deployment site within the body lumen. The deployment system and/or the stent may include radiopaque markers to permit a physician to visualize positioning of the stent under fluoroscopy prior to deployment. At the deployment site, the outer sheath is retracted to expose the stent. The exposed stent is free to self-expand within the body lumen. Following expansion of the stent, the inner tube is free to pass through the stent such that the delivery system can be removed through the body lumen leaving the stent in place at the deployment site.
[0010] In prior art devices, the stent may prematurely deploy as the outer tube is retracted accidentally. Further, once the stent has been deployed, subsequent adjustment of the stent deployment location can be difficult because re-sheathing typically cannot be readily accomplished. To overcome some of these problems some stent delivery systems are comprised of interlocks on the stent and on the inner member. See for example U.S. Pat. No. 6,814,746 to Thompson et. al., entitled “Implant Delivery System With Marker Interlock”, and U.S. Pat. No. 6,623,518 to Thompson et. al., entitled “Implant Delivery System With Interlock”, the contents of both included herein in their entirety by reference.
[0011] A common problem with stents properly deployed in some vessels is that the stents fracture over time. Problems secondary to stent fracture can include pain, bleeding, vessel occlusion, vessel perforation, high restenosis rate, non-uniform drug delivery profile, non-even vessel coverage and other problems, and re-intervention may be required to resolve the problems. Stents are commonly designed for high pulsatile fatigue life, i.e., for resistance to fracture under the diametrical pulsatile movement in an otherwise static blood vessel, as may be appropriate for some implantation sites. Stents however are not usually designed for resistance to fracture under in-patient loading conditions other than pulsatile, as is appropriate for other implantation sites. Stents at implantation sites such as the popliteal artery, iliac artery, femoral artery, tibial artery, and others can suffer from large amounts of axial, bending, or torsional cyclic loading and from large amounts of bending and twisting. It is believed that the high fracture rate of stents implanted in these locations is due to stent designs and stent material mechanical properties that are incapable of withstanding the high mechanical forces applied to the stents by patient activity over and above those forces produced by the beating heart.
[0012] Attempts have been made to improve the fatigue resistance of materials used for implantable medical devices. In U.S. Pat. No. 6,780,261 Trozera proposes use of malleable, recrystallized materials. This approach is unlikely to be suitable for many self expanding stent applications where malleability should be low. In Wu (U.S. Patent Application Publication Number 2004/0241037), Dooley (U.S. Patent Application Publication Number 2004/0216814), and Patel (U.S. Patent Application Publication Number 2005/0090844) the use of cold working or pre-straining is disclosed, and in Walak (U.S. Patent Application Publication Number 2005/0059994) use of a stabilized martensitic surface is disclosed. However, one cannot always uniformly apply these approaches to the surface of an implant because of limiting factors such as access and geometry.
[0013] What is needed is a stent that can be easily manufactured and that will survive without fracture when implanted in locations that experience high mechanical forces produced by patient activity over and above those forces produced by the beating heart.
SUMMARY OF THE INVENTION
[0014] In one embodiment, an implant comprising a nickel titanium alloy may be heat set by (a) restraining the implant on a mandrel having a first diameter and annealing the implant within a first temperature range; (b) after (a), restraining the implant on a mandrel having a second diameter and annealing the implant within a second temperature range that is higher than the first temperature range; and (c) after (b), annealing the implant within a third temperature range that is lower than the second temperature range and while the implant is restrained on a mandrel. In some embodiments, the second diameter is larger than the first diameter. Further disclosed are implants made according to the methods disclosed herein, and delivery devices that include a delivery catheter and an implant heat set according to methods disclosed herein.
[0015] In another embodiment an implant comprising a nickel titanium alloy has a bend-rotate fatigue life of at least 1 million cycles to failure. The cycles to failure is the number of full rotations made by the implant before the implant breaks.
[0016] In another embodiment, an implant is disclosed that has a nickel titanium alloy, and a kink radius of no greater than 0.195 inches, wherein the kink radius is half the distance between the implant unkinked ends held parallel to each other when the implant is kinked by bending. The implant may have a kink radius of no greater than 0.189 inches, 0.171 inches, or 0.165 inches.
[0017] In some embodiments, a delivery device includes an implant disclosed herein and a catheter for delivery of the implant.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The above and further advantages of the invention may be better understood by referring to the following description in conjunction with the accompanying drawings in which:
[0019] FIG. 1 is a side elevation view of one embodiment of a stent delivery system comprised of a fatigue resistant stent having features that are examples of inventive aspects in accordance with the principles of the present disclosure;
[0020] FIG. 2 is an enlarged view of the distal end of the system of FIG. 1 with an outer sheath shown in phantom line;
[0021] FIG. 3 is the view of FIG. 2 with the outer sheath retracted;
[0022] FIGS. 4A and 4B are side elevation views of an alternate embodiment of a stent delivery system comprised of a fatigue resistant stent;
[0023] FIGS. 5 and 6 illustrate plan views of exemplar fatigue resistant stent embodiments. The stents are shown expanded and the stent structures are shown cut longitudinally and laid flat;
[0024] FIGS. 5A and 5B illustrate plan views of exemplar fatigue resistant stent embodiments. The stents are shown unexpanded and the stent structures are shown cut longitudinally and laid flat;
[0025] FIGS. 7 and 8 illustrate side views of exemplar fatigue resistant stent embodiments. The stents are shown expanded;
[0026] FIG. 9 illustrates a plan view of an exemplar fatigue resistant stent. The stent is shown expanded and the stent and interlock structures are shown cut longitudinally and laid flat;
[0027] FIG. 10 illustrates a plan view of a section of an exemplar fatigue resistant stent. The stent is shown partially expanded and the stent segment and interlock structures are shown cut longitudinally and laid flat;
[0028] FIG. 11 illustrates a plan view of a section of an exemplar fatigue resistant stent. The stent is shown partially expanded and the stent segment and interlock structures are shown cut longitudinally and laid flat;
[0029] FIG. 12 illustrates schematically an exemplar annealing process for a fatigue resistant stent.
DETAILED DESCRIPTION
[0030] With reference now to the various drawing figures a description is provided of embodiments that are examples of how inventive aspects in accordance with the principles of the present invention may be practiced. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive aspects disclosed herein. It will also be appreciated that the inventive concepts disclosed herein are not limited to the particular stent configurations disclosed herein, but are instead applicable to any number of different stent configurations.
[0031] FIGS. 1-3 show an over-the-wire stent delivery system 10 having distal and proximal ends 11 , 13 , inner member 14 , and retractable outer sheath 16 that slides over inner member 14 . Stent mounting location 26 is located adjacent distal end 11 of system 10 . Stent 12 (visible in FIGS. 2 and 3 ) is carried at stent mounting location 26 of stent delivery system 10 in a collapsed (or reduced diameter) state. Stent 12 mounts over inner member 14 and is covered by sheath 16 so as to be retained in the collapsed state (see FIG. 2 ). Stent 12 is released (i.e., deployed) by retracting sheath 16 to uncover or expose stent 12 (see FIG. 3 ). System 10 includes proximal interlock structure 27 that prevents stent 12 from prematurely deploying, one or more mid interlock structures 28 that assist with uniform stent deployment and with stent loading, and optional distal interlock structure 29 that assists with uniform stent deployment and with stent loading. Upon release of stent 12 from stent delivery system 10 , stent 12 expands to an enlarged diameter to abut against the walls of the patient's lumen in order to support patency of the lumen. The expansion of stent 12 also causes stent 12 to disengage from interlock structures 27 , 28 and 29 .
[0032] System 10 is configured to be advanced through the patient's body lumen. In use, system 10 may be sufficiently long for distal end 11 to be placed at the deployment site in the patient's body lumen with proximal end 13 remaining external to the patient's body for manipulation by an operator.
[0033] Sheath 16 of system 10 may have a variety of different constructions. In certain embodiments, the sheath has a tubular construction of braid-reinforced polyester adapted to resist kinking and to transmit axial forces along the length of sheath 16 . Sheath 16 may be constructed so as to have varying degrees of flexibility along its length. Inner member 14 of system 10 is relatively flexible and can be made of a polymeric material such as nylon. In certain embodiments, inner member 14 has a tubular configuration and defines a lumen that extends through an entire length of inner member 14 . This type of configuration allows the system to be passed over a guidewire for guiding the system to a desired deployment location. However, in other embodiments, inner member 14 can have a solid, non-tubular configuration.
[0034] Distal end 11 of system 10 includes a tapered and flexible distal tip member 30 that is sufficiently flexible to permit advancement of stent deployment system 10 through the patient's lumen while minimizing trauma to the walls of the patient's lumen. Tip 30 is connected to inner member 14 adjacent stent mounting location 26 . Proximal end 13 of system 10 includes manifold housing 20 connected to lock housing 22 . Sheath 16 connects to manifold housing 20 . Strain relief jacket 24 surrounds sheath 16 adjacent its connection to housing 20 to provide strain relief for sheath 16 . Inner member 14 passes through both manifold housing 20 and lock housing 22 . Outer reinforcing member 32 surrounds and is bonded to inner member 14 adjacent proximal end 13 of system 10 . Reinforcing member 32 may be made of a relatively rigid material such as stainless steel. Port housing 34 is bonded to reinforcing member 32 . Port housing 34 has a bore aligned with an inner lumen of inner member 14 and functions to facilitate access to the inner lumen.
[0035] Manifold housing 20 carries admission port 42 for injecting a contrast media into the interior of manifold housing 20 . The interior of manifold housing 20 may be in fluid communication with a passage between inner member 14 and sheath 16 . In use, the contrast media can be directed from the passage into the patient's body lumen through discharge ports (not shown).
[0036] Lock housing 22 carries a threaded locking member (or lock nut) 46 which can be turned to engage reinforcing member 32 . Lock nut 46 selectively permits and fixes axially movement between the inner member and the sheath. Relative movement between the inner member and the sheath is permitted to define a transport position and a deploy position of the system 10 .
[0037] First and second handles 48 , 50 are secured to lock housing 22 and reinforcing member 32 , respectively. In the transport position, handles 48 and 50 are spaced apart and sheath 16 covers stent mounting location 26 to prevent premature deployment of stent 12 . When handles 48 and 50 are moved toward each other, sheath 16 slides rearwardly or proximally relative to inner member 14 . In other words, relative axial movement between handles 48 and 50 (represented by arrow A) results in relative axial movement between inner member 14 and sheath 16 . In particular, sheath 16 slides rearwardly from the transport position to the deploy position to fully expose stent mounting location 26 and permit stent 12 to freely expand toward its fully expanded diameter. After such expansion, the stent delivery system can be proximally withdrawn through the expanded stent and removed.
[0038] Delivery system 10 may be equipped with an interlock configuration (e.g., interlock structures 27 , 28 , or 29 of FIGS. 2 and 3 ) that constrains relative axial movement between stent 12 and inner member 14 until after sheath 16 has been fully retracted. For example, when stent 12 is mounted on inner member 14 and restrained in the compressed orientation by sheath 16 , a proximal interlock geometry located at a proximal end 12 a of stent 12 interlocks with proximal interlock geometry 27 adjacent the stent mounting location 26 , a mid interlock geometry located at one or more locations along length of stent 12 interlocks with a mid interlock geometry 28 adjacent the stent mounting location 26 , and a distal interlock geometry located at a distal end 12 b of stent 12 interlocks with a distal interlock geometry 29 adjacent the stent mounting location 26 . The interlock geometries remain interlocked to constrain axial movement of stent 12 until after the sheath has been retracted beyond a predetermined location (e.g., the proximal-most end 12 a of stent 12 ). When sheath 16 has been retracted beyond the predetermined location, the interlock geometry of stent 12 is allowed to expand. As the interlock geometry of the stent expands, the interlock geometry of stent 12 disengages from the proximal, mid, and distal interlock geometries thereby allowing inner member 14 of system 10 to be moved axially relative to the stent without interference from the interlock geometries. Stent interlocks are further described in co-pending U.S. patent application No. 60/800,106 entitled “IMPLANT AND DELIVERY SYSTEM WITH MULTIPLE MARKER INTERLOCKS” and filed on May 12, 2006, U.S. patent application Ser. No. 10/982,537 entitled “IMPLANT DELIVERY SYSTEM WITH MARKER INTERLOCK” filed on Nov. 4, 2004, U.S. Pat. No. 6,814,746 entitled “STENT DELIVERY SYSTEM WITH RETAINER” which issued on Jun. 28, 2004, U.S. Pat. No. 6,623,518 entitled “IMPLANT DELIVERY SYSTEM WITH INTERLOCK” which issued on Mar. 25, 2003, and U.S. patent application Ser. No. 09/954,555 entitled “IMPLANT DELIVERY SYSTEM WITH INTERLOCK” which was filed on Sep. 17, 2001, each of which is incorporated by reference in their entirety herein.
[0039] Stent 12 has a length L and a circumference C, and includes a plurality of struts 86 (i.e., reinforcing members). At least some of the struts 86 have free terminal ends 72 that define proximal and distal ends 12 a and 12 b of the stent 12 . The stent 12 includes interlock geometry in the form of enlargements 47 positioned at the free terminal ends of the struts 86 . As shown in FIG. 3 , the enlargements are circular enlargements. It will be appreciated that other shapes and interlock configurations could also be used. The enlargements 47 project outwardly from the struts 86 in a circumferential direction (i.e. in a direction coinciding with the circumference C of the stent 12 ). In certain embodiments, the stent 12 can be manufactured by cutting (e.g., laser cutting) the various features from a solid tube of material. When manufactured by this technique, the enlargements 47 do not project radially beyond an inner and outer diameter of the stent.
[0040] FIGS. 4A and 4B illustrate an alternate embodiment of a stent delivery system. Rapid exchange stent delivery system 60 includes sheath 66 and inner member 64 disposed within sheath. Manifold housing 70 is coupled to sheath 66 . Housing 70 includes side arm 72 and locking member 74 . Push wire 68 is coupled to inner member 64 at its distal end and to handle 80 at its proximal end. Inner member 64 and sheath 66 are axially slideable relative to one another. Push wire 68 and housing 70 are used to facilitate movement of inner member 64 relative to sheath 66 . Locking member 74 can be operated to couple housing 70 to push wire 68 in order to slide both sections along together. Relative movement between the inner member and the sheath is permitted to define a transport position and a deploy position of the system 60 . Stent (not shown) mounts over inner member 64 and is covered by sheath 66 so as to be retained in the collapsed state. The stent is released (i.e., deployed) by retracting sheath 66 to uncover or expose stent. System 60 includes proximal interlock structure (not shown) that prevents stent from prematurely deploying, one or more mid interlock structure (not shown) that assist with uniform stent deployment and with stent loading, and one or more distal interlock structure (not shown) that assist with uniform stent deployment and with stent loading. Upon release of stent from stent delivery system 60 , stent expands to an enlarged diameter to abut against the walls of the patient's lumen in order to support patency of the lumen. The expansion of stent also causes stent to disengage from proximal, mid, and distal interlock structures.
[0041] Sheath 66 may be made of kink resistant extruded polymer tubing with adequate strength and lubricity for unsheathing a stent. Polymers such as nylon, PEBAX, polyethylene, or polyester may be used. Alternatively, thermoset polymers such as polyimide or braid reinforced polyimide may be used. In some embodiments the distal portion of the outer member is transparent to allow inspection of the stent within. Inner member 64 may be made of flexible kink resistant polymer such as metallic braid reinforced polyimide, although polymers such as nylon, PEBAX, polyethylene, or polyester may be used. Push wire 68 may be constructed of metal. In certain embodiments the proximal portion of push wire is comprised of stainless steel tubing and the distal portion of push wire 68 is comprised of metal wire. This combination provides adequate column strength throughout, good bending resistance proximally, and good bending flexibility distally. Housing 70 and locking member 74 may be comprised of polycarbonate, polystyrene, or other materials, and a sealing gland (not shown) may be used in cooperation with housing 70 and locking member 74 to effect a fluid seal and/or mechanical lock between housing, locking member, and push wire 68 as is well known in the art. Handle 80 may be comprised of polycarbonate, polystyrene, nylon, or other materials. Alternate materials for these components are generally well known in the art can be substituted for any of the non-limiting examples listed above provided the functional requirements of the component are met.
[0042] Guidewire 90 has a nominal outer diameter of 0.010″-0.038″, such as 0.014″. Inner member 64 is dimensioned to allow low friction passage of guidewire 90 within guide wire lumen 95 and through RX port 97 . Guide wire lumen length can vary widely, for example within the range from 5 cm to 50 cm in length. In certain embodiments guide wire lumen 95 is approximately 30 cm in length. Sheath maximum outside diameter can range from about 10 Fr to about 3 Fr. A sheath outside diameter of about 5 Fr is desirable for compatibility with currently popular guide catheter (not shown) dimensions. Sheath length can be varied to suit the application of interest. Sheath lengths of 40 cm-200 cm have been found desirable. In certain embodiment a sheath length of about 145 cm has been used.
[0043] FIGS. 5-9 illustrate a variety of fatigue resistant stents having different characteristics. FIG. 5 illustrates expanded stent 52 similar to stent 12 shown in FIGS. 2 , 3 , and 4 and having enlarged ends 47 and mid-stent retainer pockets 12 y that both interlock with interlock geometry of a delivery catheter. Stent 52 has cells 18 , each cell comprised of six strut bend regions 19 . Stent cells 18 are connected to adjacent cells 18 by means of interconnection regions 23 . Interconnection regions 23 are not aligned opposite to one another in adjacent cells 18 with regards to the lengthwise axis of the stent. Interconnection regions 23 have lengths along the length of stent 52 . Interconnection region 23 length is between approximately 0.5% and 5% of cell length with respect to the axial direction of stent length L. In certain embodiments interconnection region 23 length is between 0.5% and 3% of cell length. In some embodiments interconnection region 23 length is between 0.5% and 1.5% of cell length. Stent 52 may be comprised of metal, polymer, ceramic, permanent enduring materials, or bioabsorbable materials. Bioabsorbable stents 52 can be polymeric, bio-polymeric, ceramic, bio-ceramic, or metallic, or may be made from combinations of these materials. Bioabsorbable and non-bioabsorbable stents 52 may elute over time substances such as drugs.
[0044] FIGS. 5A and 5B illustrate unexpanded stent 52 a . Stent 52 a is similar to stent 52 and has enlarged ends 47 and mid-stent retainer pockets 12 y that both interlock with interlock geometry of a delivery catheter. Stent 52 has cells 18 (not shown), each cell comprised of six strut bend regions 19 . Stent cells 18 are connected to adjacent cells 18 by means of interconnection regions 23 . Interconnection regions 23 are not aligned opposite to one another in adjacent cells 18 with regards to the lengthwise axis of the stent. Interconnection regions 23 have lengths along the length of stent 52 . Interconnection region 23 length is between approximately 0.5% and 5% of cell length with respect to the axial direction of stent length L. Stent 52 a may have the specific dimensions as delineated in FIGS. 5A and 5B , and all such dimensions may be laser cut without any finishing. Stent 52 a is finished by processes such as microgrit blasting to remove slag, electropolishing to remove stent material having heat affected zone and other imperfections, and surface passivation to render surface of stent 52 a more resistant to corrosion. The dimensions shown in the figures are merely illustrative and should not be considered limitations of the invention.
[0045] FIG. 6 illustrates expanded fatigue resistant stent 53 comprised of mesh 82 . Mesh 82 may be comprised of intertwined, joined, or non-woven filaments 81 . In some embodiments filaments 81 are braided, woven, knitted, circular knitted, compressed, or otherwise fabricated into a porous mesh structure having cells 18 p . Filaments 81 may be joined at one or more crossings 83 by sintering, bonding, soldering, fusing, welding, or other means. In other embodiments mesh 82 is comprised of a tube having cells 18 p formed through the wall of the tube, by means such as laser cutting, electrochemical etching, grinding, piercing, or other means. In some embodiments mesh 82 is formed by electroforming. Stent 53 may have one or more enlarged ends 47 . Enlarged ends 47 may be formed integral to the stent, for example in a stent made using electroforming manufacturing methods, or may be joined to stent 53 , for example in a stent made by braiding, using methods known in the art such as welding or fusing. Stent 53 has one or more retainer pockets 12 p . One or more enlarged end 47 and retainer pocket 12 p together with interlocking structure of a stent delivery catheter may comprise an interlocking stent delivery system. Stent 53 may be comprised of metal, polymer, ceramic, permanent enduring materials, or bioabsorbable materials. Bioabsorbable stents 53 can be polymeric, bio-polymeric, ceramic, bio-ceramic, or metallic, or may be made from combinations of these materials. Bioabsorbable and non-bioabsorbable stents 53 may elute over time substances such as drugs.
[0046] FIGS. 7 and 8 illustrate alternate fatigue resistant stent embodiments. Coil stents 110 , 120 are comprised of ribbon 111 having widths W and W′, respectively, wound into a hollow cylinder form and having a wind angles A and A′, respectively. Stent 120 is comprised of ribbon 111 having width W′ less than width W of ribbon in stent 110 , and having wind angle A′ greater than wind angle A of ribbon in stent 110 . Ends 112 of ribbon may be rounded to prevent tissue damage or tissue irritation in vicinity of ends 112 when stent 110 , 120 is implanted into a patient. Ribbon 111 may be comprised of metal, polymer, ceramic, permanent enduring materials, or bioabsorbable materials. Bioabsorbable ribbons 111 can be polymeric, bio-polymeric, ceramic, bio-ceramic, or metallic, or may be made from combinations of these materials. Bioabsorbable and non-bioabsorbable ribbons 111 may elute over time substances such as drugs.
[0047] Ribbon 111 is comprised of an expandable architecture 130 also suitable for use a coiled ribbon illustrates in FIGS. 7 and 8 . One example of an expandable architecture 130 is illustrated in FIG. 9 . Ribbon 111 is shown partially expanded and the ribbon and interlock structures are shown cut longitudinally and laid flat. Expandable architecture 130 is comprised of enlarged ends 47 , mid-stent retainer pockets 12 y , struts 86 , bend regions 19 , and one or more interconnection regions 113 . Struts 86 and bend regions 19 together form a zig-zag shaped expandable architecture of ribbon 111 . Other expandable architectures are contemplated for expandable architecture of ribbon 111 such as various serpentine or meandering paths. Interconnection regions 113 join adjacent ribbons 111 and can fracture in a controlled manner such that when fractured interconnection regions 113 no longer join adjacent ribbons 111 .
[0048] FIG. 10 illustrates interconnection regions 113 that comprise holes 114 in bend regions 19 and one or more strand 115 . Strand 115 passes through holes 114 along a pathway that joins together adjacent ribbons 111 a and 111 b . In the example illustrated in FIG. 10 , strand 115 passes through holes 114 in adjacent bend regions 19 and forms a closed loop. Many other strand pathways are possible, such as a single strand 115 passing through holes 114 of multiple bend regions 19 , and other configurations as are apparent to those skilled in the art. Strand 115 is comprised of a material that fractures in a controlled manner, and may be formed of biodegradable suture or other materials. In an alternate embodiment interconnection regions 113 are comprised of a biodegradable coupling such as a tube that surrounds bend regions 19 . In another alternate embodiment, interconnection regions 113 are comprised of a biodegradable rivet that passes through holes 114 in adjacent bend regions 19 .
[0049] FIG. 11 illustrates another example of an expandable architecture 130 . A fractional portion of ribbon 111 is shown partially expanded and the ribbon and interlock structures are shown cut longitudinally and laid flat. Expandable architecture 130 is comprised of cells 18 , enlarged ends 47 , mid-stent retainer pockets 12 y , struts 86 , bend regions 19 , and one or more interconnection regions 113 . Struts 86 and bend regions 19 together form a cellular expandable architecture of ribbon 111 with similarities to the cellular structures described in connection with at least FIGS. 2 , 3 and 5 . Interconnection regions 113 join adjacent ribbons 111 and can fracture in a controlled manner such that when fractured, interconnection regions 113 no longer join adjacent ribbons 111 . Interconnection regions 113 may be comprised of expanded ends 116 and receiver ends 117 , interdigitating ends 118 , or other structures.
[0050] Coil stent architectures which may be incorporated as part of fatigue resistant stents are further described in U.S. patent application No. 60/674,859 entitled NON-FRACTURE STENT DESIGN which was filed on Apr. 25, 2005, and subsequently also filed as PCT/US06/15596 entitled CONTROLLED FRACTURE CONNECTIONS FOR STENT filed on Apr. 25, 2006, and each which is incorporated by reference in their entirety herein.
[0051] The invention contemplated is suitable for stents in addition to those cited herein. For example, fatigue resistant stents may comprise tapered stents, flared stents, braided stents, bifurcation stents, and other stents as are known in the art. Tapered stents generally have a proximal end of one diameter and a distal end of a second diameter (typically a smaller diameter). Flared stents generally have a short tapered portion at the proximal end of a cylindrical stent, where the flared section is larger in diameter than the cylindrical portion. Braided stents are typically comprised of a tube manufactured by using a braiding method. An example of a braided stent is the Wallstent, sold by Boston Scientific, Natick, Mass. Bifurcation stents are placed in a patient where a vessel branches. Bifurcation stents are generally comprised of a single stent portion that branches into two stent portions and appears similar to a Y-fitting used to connect one piece of tubing to two pieces of tubing.
[0052] In certain embodiments fatigue resistant stents are comprised of superelastic material, such as binary Nitinol alloys with nominal composition of 50-52 atomic percent nickel and the balance of the material comprised of titanium. In some embodiments the superelastic material is comprised of ternary or quaternary nitinol alloys having a nickel/titanium ratio of 1/1 to 1/1.3. In certain embodiments the superelastic material is comprised of binary Nitinol tubing having a composition of about 50.8 atomic percent nickel (about 56 weight percent nickel) and the balance of the material comprised of titanium with small amounts of impurities, the overall composition, structure, and properties falling within the requirements of ASTM Standard F-2063-05. Such material is available under order number SE508 from NDC Corporation of Fremont, Calif. In certain embodiments the superelastic material is comprised of binary Nitinol tubing having a composition of about 50.8 atomic percent nickel (about 56 weight percent nickel) and the balance of the material comprised of titanium with small amounts of impurities.
[0053] In some embodiments, Nitinol is heat treated to improve the fatigue life of the material. One example of a manufacturing process for a 6 mm fatigue resistant stent is illustrated in FIG. 12 and described below. Cold worked Nitinol tubing (approximately 40% cold work and approximate A F of −10° C.) having an outside diameter of 0.060″ and a wall thickness of 0.0105″ is optionally stress annealed and then apertures may be laser cut through the wall of the tubing. The cut tube is expanded by forcing the cut tube onto a 2.0 mm outside diameter mandrel having a tapered end (first expansion). After first expansion the tubing is annealed on the 2.0 mm mandrel at 485±3° C. for 1 minute after which the A F will be approximately +30° C. Intermediate expansions are carried out by forcing the cut tube onto successive 3.0 mm, 4.0 mm, and 5.0 mm outside diameter mandrels, each having a tapered end, with successive anneals of the tubing on each of the 3.0 mm, 4.0 mm, and 5.0 mm mandrels at 485±3° C. for 1 minute for each anneal. After the intermediate expansions the A F will be approximately +30° C. Final expansion is carried out by forcing the cut tube onto a 6.0 mm outside diameter mandrel having a tapered end and is followed by annealing the tubing on the 6.0 mm mandrel at 600±2° C. for 45-60 seconds and then at 485±3° C. for 5 minutes on the same 6.0 mm mandrel. After the 600° C. anneal the A F will be approximately +22° C. and after the final 485° C. anneal the A F will be approximately −15° C. to −20° C. The 485° C. first and intermediate anneals will shape set the Nitinol and raise the austenite finish temperatures (A F ) to a level unsuitable for use as a stent in a patient. The 600° C. anneal will dissolve nickel rich precipitates in the material and the resultant more homogeneous material will be less prone to fatigue fracture. The 600° C. anneal will also lower the A F somewhat. The final 485° C. anneal will shape set the Nitinol and further lower the A F to a level suitable for use as a stent in a patient. In certain embodiments, Nitinol tubing having a composition of about 50.8 atomic percent nickel (about 56 weight percent nickel) and the balance of the material comprised of titanium, after being subjected to the heat treatment described above, will have an upper plateau stress of 355±7.2 MPa, a lower plateau stress of 104±7.2 MPa, an ultimate tensile stress of 1,088±51 MPa, and an elongation of 15.4±2.2% (measured in tension).
[0054] Properties of stents can be measured in many ways. Particularly useful measurements include kink radius, flexural peak load, flexural modulus, and bend-rotate fatigue life. Kink radius is measured using the following method. A calibrated ruler is placed on a table and a stent is held by the ends with the long axis of the stent parallel to the table surface and parallel to the ruler. The stent is bent until it kinks. With the un-kinked ends of the stent parallel to each other the distance between the un-kinked parallel ends of the stent is measured using the ruler. The measurement is divided in half to arrive at the stent kink radius. The stents are preconditioned to 37° C. for at least one hour prior to kink testing, and are tested at ambient conditions.
[0055] Flexural peak load and flexural modulus are measured by 3-point bending using the following method. A stent is loaded into a fixture having 3 mandrels oriented parallel to each other and at 90° to the long axis of the stent. Two of the mandrels are aligned horizontally below the stent and the third mandrel is aligned above the stent and midway between the two mandrels below the stent. The separation of the mandrels (span length) below the stent is prescribed according to the table below.
[0000]
Stent Length (mm)
Span Length (mm)
10-14
6
15-19
11
20-24
16
25-35
21
>35
Stent Length minus 4 mm
[0056] The mandrel above the stent is advanced towards the axis of the stent on a testing machine having tensile and compressive capabilities and a recordation of force and displacement applied to the stent is recorded. The flexural peak load is the maximum force value in the force-displacement curve. The flexural modulus is the slope of the linear portion of the force-displacement curve. The stents are preconditioned to 37° C. in body temperature water bath for at least one minute prior to 3-point bending testing, and are tested at ambient conditions.
[0057] Bend-rotate fatigue life is measured using the following method (the method is based on DIN 50113 (German Institute for Standardization)). Each end of a stent is mounted concentrically on the end of a post and the posts are rotated at the same frequency. The rotational axes of the posts are oriented at an angle of 90° to each other. The distance between the posts is adjusted until the smallest radius along the length of the outer diameter of the stent (worst case bending radius) is 26 mm. The stent is rotated at ≦10 Hz until the stent fractures. The cycles to failure is the number of full rotations made by the stent before the stent breaks. The test environment for bend-rotate fatigue is in air at 37° C.
[0058] Stents manufactured according to the techniques and methods disclosed herein have exceptional fatigue resistance as shown in the examples below.
Example 1
[0059] A 6 mm diameter stent having a structure as shown in FIGS. 5A and 5B was laser cut from binary nitinol alloy tubing SE508 (NDC Corporation, Fremont, Calif.) and expanded and heat treated using the exemplar processes described in conjunction with FIG. 12 (hereinafter referred to as “Stent 6X”) to produce material having an upper plateau stress of 355±7.2 MPa and a lower plateau stress of 104±7.2 MPa, an ultimate tensile stress of 1,088±51 MPa, and an elongation of 15.4±2.2%. Stent 6X and competitive 6 mm stents were tested for kink radius, flexural properties, and bend-rotation fatigue endurance. Bend-rotation fatigue endurance subjected the stent struts to a maximum strain of ±3.5%. Percentage strain is defined as change in length divided by original length. Highest strain values are at the stent outer surface, as calculated by finite element analysis using material parameters derived from uncut stent tubing subjected to the same thermomechanical history as stents laser cut from the same tubing. As the table below shows, stent 6X has superior measured characteristics as compared to those of competitive stents.
[0000]
Flexural
Kink Radius
Cycles to
Modulus
Flexural Peak
Stent
(inches)
Failure (#)
(g/mm)
Load (g)
Competitor B
23,315
10.03
18.18
Competitor CP
0.375
Competitor CS
667,974
7.96
15.99
Competitor CZ
3.56
6.56
Competitor G
151,371
1.39
3.37
Stent P
0.494
18.46
36.16
Stent 6X 1,2
0.189
>20,000,000
4.33
8.63
0.171
3.90
8.61
1 Two data sets for kink radius were generated
2 Two data sets for flexural properties were generated
Example 2
[0060] A 7 mm diameter stent having a structure substantially similar to that shown in FIGS. 5A and 5B was laser cut from binary nitinol alloy tubing SE508 (NDC Corporation, Fremont, Calif.) and expanded and heat treated using expansion, annealing, and other processes substantially similar to those described in conjunction with FIG. 12 to produce material having an upper plateau stress of 355±7.2 MPa and a lower plateau stress of 104±7.2 MPa, an ultimate tensile stress of 1,088±51 MPa, and an elongation of 15.4±2.2%; it is hereinafter referred to as “Stent 7X”. Stent 7X and competitive 7 mm stents were tested for bend-rotation fatigue endurance. As the table below shows, stent 7X has superior measured characteristics as compared to those of a competitive stent.
[0000]
Flexural
Kink Radius
Cycles to
Modulus
Flexural Peak
Stent
(inches)
Failure (#)
(g/mm)
Load (g)
Competitor B
7,800
Competitor CS
150,000
Stent 7X
>10,000,000
Example 3
[0061] An 8 mm diameter stent, having a structure substantially similar to that shown in FIGS. 5A and 5B was laser cut from binary nitinol alloy tubing SE508 (NDC Corporation, Fremont, Calif.) and expanded and heat treated using expansion, annealing, and other processes substantially similar to those described in conjunction with FIG. 12 to produce material having an upper plateau stress of 355±7.2 MPa and a lower plateau stress of 104±7.2 MPa, an ultimate tensile stress of 1,088±51 MPa, and an elongation of 15.4±2.2%. The stent described in the above sentence is hereinafter referred to as “Stent 8X”. Along with competitive 8 mm stents, it was tested for kink radius, flexural properties and bend-rotation fatigue endurance. As the table below shows, stent 8X has superior measured characteristics as compared to those of competitive stents.
[0000]
Flexural
Kink Radius
Cycles to
Modulus
Flexural Peak
Stent
(inches)
Failure (#)
(g/mm)
Load (g)
Competitor A
0.400
Competitor B
8,758
Competitor CP
0.475
Competitor CS
0.375
12,084
Competitor G
549,570
Stent 8X 1
0.195
>10,000,000
4.46
9.10
0.165
1 Two data sets for kink radius were generated
[0062] In certain embodiments of the invention, the stents of the invention may be designed to resist fracture (as measured by bend-rotate fatigue test) over at least 100,000 cycles, at least 200,000 cycles, at least 500,000 cycles, at least 1,000,000 cycles, at least 2,000,000 cycles, at least 5,000,000 cycles, at least 10,000,000 cycles, or at least 20,000,000 cycles.
[0063] An exemplar method of using a stent delivery system to deliver a fatigue resistant stent into a body of a patient is now described. Using techniques well known in the art, a guidewire is percutaneously inserted into a patient's blood vessel and advanced to a region of interest in the patient's body. Using imaging techniques such as fluoroscopy the diseased portion of the vessel is identified and a stent having the correct length and diameter for a treatment site is chosen. With reference to FIGS. 1 , 2 , 3 , 4 A, 4 B, 5 , 5 A and 5 B self expanding stent delivery system 10 , 60 is advanced over the guidewire to the treatment site and by using imaging techniques such as fluoroscopy both ends 12 a , 12 b of stent 12 are positioned at a correct location relative to the treatment site.
[0064] Inner member 14 , 64 is held stationary and sheath 16 , 66 is withdrawn to expose stent 12 . Stent 12 expands into contact with a lumenal wall of the vessel as sheath 16 , 66 is withdrawn. Distal interlock 26 prevents stent from compressing axially when sheath 16 , 66 is withdrawn, thereby facilitating deployment of distal end 12 b of expanded stent at the correct location and reducing forces required to withdraw sheath 16 , 66 . Mid interlocks 28 (if used) prevent stent from compressing axially when sheath 16 , 66 is withdrawn thereby reducing forces required to withdraw sheath 16 , 66 . Proximal interlocks 27 secure stent to stent delivery catheter until sheath 16 , 66 is withdrawn proximally to stent end 12 a , thereby reducing forces required to withdraw sheath 16 , 66 and facilitating deployment of proximal end 12 a of expanded stent at the correct location. After, and optionally, during stent deployment, stent markers 15 are imaged for various reasons including evaluating deployed stent position relative to treatment site, evaluating extent of stent diametrical expansion, and other reasons.
[0065] Following implantation of a fatigue resistant stent into a patient the patient may return to the implanting physician for a followup visit. During followup the markers 15 of implanted stent 12 , stent 12 , or both may be imaged using imaging techniques such as fluoroscopy, ultrasound, or magnetic resonance imaging to assess whether or not stent 12 has fractured, or for other reasons.
[0066] While the various embodiments of the present invention have related to stents and stent delivery systems, the scope of the present invention is not so limited. For example, it will be appreciated that the various aspects of the present invention are also applicable to other types of expandable implants and their delivery systems. By way of non-limiting example, other types of expanding implants that can benefit from application of the invention include anastomosis devices, blood filters, grafts, vena cava filters, percutaneous valves, aneurism treatment devices, or other devices.
[0067] Modifications and equivalents of the disclosed concepts are intended to be included within the scope of the claims. Further, while choices for materials and configurations may have been described above with respect to certain embodiments, one of ordinary skill in the art will understand that the materials and configurations described are applicable across the embodiments.
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According to one aspect of the present invention, a fatigue resistant stent comprises a flexible tubular structure having an inside diameter, an outside diameter, and a sidewall therebetween and having apertures extending through the sidewall. According to other aspects of the invention, processes for making a fatigue resistant stent are disclosed. According to further aspects of the invention, delivery systems for a fatigue resistant stent and methods of use are provided.
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FIELD OF THE INVENTION
The present invention relates to the field of bridge plugs for use in a well bore and, in particular, to retrievable bridge plugs used in an oil well bore.
BACKGROUND OF THE INVENTION
Bridge plugs are commonly used to isolate sections of a well, particularly where pressure differentials will result from perforating or drilling in a number of hydrocarbon formations along the well bore. These plugs can also be used to block off well bores which are no longer in use.
Retrievable bridge plugs are generally run downhole to a desired depth using a setting tool. The plugs can be run on electric lines, hydraulic lines, and solid wire lines and are set in position, for example, with an electric wireline setting assembly. The bridge plug can be retrieved using a retrieving tool on a slick line, branded line, coiled tubing or other means.
Bridge plugs generally in use today have a number of disadvantages. They are not adapted for easy use with smaller diameter tubing. When the bypass valve is released to equalize any pressure differential and clear debris in the tubing, the bridge plug also releases. Also, they require at least two trips with a running tool to release and retrieve the plug. This results in a substantial increase in the cost and man hours required to utilize the plug.
SUMMARY OF THE INVENTION
There therefore is provided a bridge plug for use in a well bore which overcomes the disadvantages of the prior art and which includes a sealing and anchoring mechanism.
The bridge plug of the present invention is retrievable in one run. It includes dual sealing and anchoring mechanisms which are not released when a bypass valve is activated to equalize any pressure differentials.
In one aspect of the present invention there is provided a bridge plug for use in a well bore for engagement with the tubing wall of the bore, said bridge plug comprising: mandrel means having an elongated body extending along a longitudinal axis and having a bore extending therethrough; sealing means disposed on said mandrel means and including sealing elements wherein the sealing elements are expandable in an outwardly direction from the longitudinal axis when said elements are compressed to engage the tubing wall; anchoring means disposed on said mandrel means and including a first and second sleeve means having radially inwardly sloped surfaces and anchoring members having a sloped surface corresponding to said sloped surfaces on said first and second sleeve means, said sloped surfaces on said first and second sleeve means cooperating to force the anchoring member radially outwardly upon movement of said first sleeve means towards said second sleeve means whereby the slip member is forced into engagement with the tubing wall; ratchet means disposed on said mandrel means for engaging said sealing means and said mandrel means; and an upper housing assembly slidably disposed on said mandrel means, said upper housing assembly movable in a downward direction along the longitudinal axis forcing said sealing elements to compress and engage the tubing wall and forcing said first sleeve towards said second sleeve.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the present invention may be better understood with reference to the drawings in which:
FIG. 1 is a side perspective partial cross-sectional view of one embodiment of the bridge plug of the present invention.
FIG. 2 is a side perspective partial cross-sectional view of the inner mandrel of the bridge plug of FIG. 1.
FIG. 3 is a side perspective partially cross-sectional view of the latch of the bridge plug of FIG. 1.
FIG. 4 is a side perspective partial cross-sectional view of the bypass valve housing of the bridge plug of FIG. 1.
FIG. 5 is a side perspective partially cross-sectional view of the collar of the bridge plug of FIG. 1.
FIG. 6 is a side perspective partially cross-sectional view of the element of the bridge plug of FIG. 1.
FIG. 7 is a side perspective partially cross-sectional view of the spacer of the bridge plug of FIG. 1.
FIG. 8 is a side perspective partially cross-sectional view of the element seat of the bridge plug of FIG. 1.
FIG. 9 is a side perspective partial cross-sectional view of the rubber mandrel of the bridge plug of FIG. 1.
FIG. 10 is a side perspective partially cross-sectional view of the upper cone of the bridge plug of FIG. 1.
FIG. 11 is a side perspective partially cross-sectional view of the slip cage of the bridge plug of FIG. 1.
FIG. 12 is a side perspective partial cross-sectional view of a slip of the bridge plug of FIG. 1.
FIG. 13 is a side perspective partially cross-sectional view of the lower cone of the bridge plug of FIG. 1.
FIG. 14 is a side perspective partially cross-sectional view of the bottom sleeve of the bridge plug of FIG. 1.
FIG. 15 is a side perspective partially cross-sectional view of an alternate latch for the bridge plug of FIG. 1.
FIG. 16 is a side perspective partially cross-sectional view of the ratchet sleeve of the bridge plug of FIG. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to the Figures, the present invention is a retrievable bridge plug for use in well bores and preferably in oil well bores. The bridge plug includes a dual sealing and anchoring system for engaging the pipe or tubing wall to ensure a tight fit for prevention of any pressure leaks or slippage of the plug.
The bridge plug has a longitudinal axis L, an uphole end U and a downhole end D. Each of the figures is positioned in an uphole to downhole orientation. One embodiment of the assembled plug 1 is shown in FIG. 1.
The bridge plug 1 comprises a mandrel, sleeves concentrically disposed about the mandrel along its longitudinal axis L, a sealing mechanism, an anchoring mechanism, and a ratchet assembly for releasably locking the sealing and anchoring mechanisms in engagement with the tubing wall.
The bridge plug 1 has, at its uphole end U, a shear stud 3 and coupling 5, shown in FIG. 1, for attaching the plug 1 to a setting tool. The shear stud 3 comprises a short rod extending along the longitudinal axis L of the plug 1. It has threaded portions at its upper and lower ends. At or near the centre of the stud 3 is an annular groove 7. The coupling 5 is a tubular portion having internally threaded sections. The downhole threaded portion of the shear stud 3 engages the uphole threaded portion of the coupling 5. The uphole threaded portion of the shear stud 3 engages the setting tool. The setting tool attaches to the shear stud 3 and, once the plug 1 is set, as will be described in detail below, the setting tool shears off the stud 3 at the annular indentation 7 to leave the bridge plug 1 in set engagement with the tubing wall. The shear stud 3 is selected according to the pressure required to set the plug 1 and to shear the stud 3.
An inner mandrel 9 shown in FIG. 2 engages the lower end of the shear stud coupling 5. The inner mandrel 9 is an elongated tubular rod extending longitudinally L in the centre of the bridge plug 1. The inner mandrel 9 has a threaded portion at its uphole end which engages the shear stud coupling 5 and a threaded portion at its downhole end. Near its uphole end is a series of annular indentations and ribs. In particular, the inner mandrel has projections 10,11 which extend outwardly from the mandrel 9 forming a seat 12 and an annular groove 14.
A number of sleeves are concentrically disposed about the inner mandrel 9 and slidably movable thereon. These sleeves include a latch 13, bypass valve housing 19, upper cone 27, and lower cone 31.
Shown in FIG. 3 is a latch 13. An alternative embodiment incorporated into the plug of FIG. 1 is shown in FIG. 15. The latch 13 is positioned on the inner mandrel 9 below the shear stud 3 and coupling 5. It is secured to the inner mandrel 9 by shear pin 17. The latch 13 has an outwardly projecting lip 15 at its uphole end. This lip 15 engages the retrieving tool which will be described in greater detail below. In the alternative embodiment 14 shown in FIG. 15, the alternate latch 14 has a threaded portion at its upper end for engaging the retrieving tool. The alternate latch 14 requires a latch key 16 shown in FIG. 1.
Positioned below the latch 13 is the bypass valve housing 19. The housing 19, shown in FIG. 4, includes an opening 23 and grooves 25 for receiving o-rings. The housing 19 slides downward along the mandrel to an open position during the retrieving stage where the opening 23 aligns with an opening 66 in the ratchet sleeve 51, described below, to allow air, gas, or liquids to pass through an opening between the inner mandrel 9 and the ratchet sleeve 51 to equalize pressure between the uphole and downhole portions above and below the bridge plug when it is in a set position. This flow will eliminate any pressure differentials while the sealing mechanism remains set.
Positioned near the downhole end of the inner mandrel 9 are the upper 27 and lower cones 31 shown in FIGS. 10 and 13 respectively. These cones are also concentrically disposed about the inner mandrel 9 and slidable thereon. The upper cone 27 has a threaded portion at its uphole end. At its downhole end, it has a section with radially inwardly sloped surfaces 29 forming a ramp. The inner surface 30 of this sloped portion 29 is flat lying flush along the surface of the ratchet sleeve 51 along the longitudinal axis L of the plug 1. The outer surface forms a step portion having an annular shoulder 28. The lower cone 31 is disposed over the inner mandrel 9 downhole of the upper cone 27. It has an uphole portion with a radially inwardly sloped outer surface 33 forming a ramp. On its inner surface, the lower cone 31 has a recessed portion 43 extending between two inwardly projecting stops 45, 47 positioned one at each end of the lower cone 31. The uphole stop 45 has a flat inner surface 46 extending along the longitudinal axis L of the plug 1.
Disposed about the inner mandrel 9, extending between the upper 27 and lower cone 31, and overlapping the sloped surfaces 29, 33 of each is a slip cage 35. The slip cage 35 is shown in FIG. 11. It has an upper rim 36 extending inwardly engaging the annular shoulder 28 of the upper cone 27. It is attached to the lower cone 31 by set screw 39. The set screw 39 is positioned in a short slot on the slip cage 35 to allow the slip cage to slide downwards as the upper cone moves downward during the setting stage which will be described below. The slip cage 35 has a number of openings or windows 37.
Positioned at the downhole end of the inner mandrel 9 is a bottom sleeve 41 shown in FIG. 14. The bottom sleeve 41 threadedly engages the downhole end of the inner mandrel 9. The lower cone 31 extends downwardly over the uphole end of the bottom sleeve 41.
A ratchet 53 and ratchet sleeve 51 is disposed about the inner mandrel 9 and positioned between the inner mandrel 9 and the housings 13,19,27. The ratchet sleeve 51 is shown in FIG. 16. It extends along the longitudinal axis L of the plug and includes an elongated main body 52 and collets 55,57. The collets 55,57 consist of a series of flexible arms extending from the uphole and downhole ends of the main body 52. The collets 55,57 have stops 59,61 projecting from their free ends. The stops 59 on the collets 55 at the uphole end of the ratchet sleeve 51 project inwardly into the recess 12 formed between the projections 10,11 on the inner mandrel 9. The stops 61 on the collets 57 at the downhole end of the ratchet sleeve 51 project outwardly and engage the lower edge of the projection 47 on the downhole end of the lower cone 31 retaining the lower cone 31 in position. The ratchet sleeve 51 also includes a downhole portion 63 having a wider diameter than the main body 52 of the ratchet sleeve 51. It meets the main body 52 at annular shoulder 65. The main body 52 immediately above the annular shoulder 65 is threaded for engaging the ratchet 53. The ratchet sleeve 51 is attached to the bypass valve housing by shear pin 21 and to the collar 71 by shear screw 67. On the main body 52, there is an opening 66 near the uphole end. This opening 66 opens into a passage extending between the ratchet sleeve 51 and the inner mandrel 9 in the longitudinal direction L towards the downhole end of the bridge plug 1. In the assembled plug, prior to setting, opening 66 lies between grooves 25. During the retrieving stage, the housing 19 is moved in a downward direction and the opening 23 in the housing 19 will communicate with opening 66 to allow the flow of air, gas, and/or liquids from above and below the set bridge plug to equalize the pressure before the plug is removed.
The ratchet 53 is concentrically disposed about the ratchet sleeve 51. It threadedly engages the ratchet sleeve 51 and rubber mandrel 79 and locks the sealing mechanism in a set position as will be described in greater detail below.
The plug 1 includes a sealing mechanism. The sealing mechanism includes a collar 71, elements 73, spacer 75, element seat 77, and a rubber mandrel 79.
The collar 71 is shown in FIG. 5. It is slidably disposed about the inner mandrel 9 and the ratchet sleeve 51. The uphole end of the collar 71 engages the downhole end of the bypass valve housing 19. Its downhole portion has a larger diameter than the uphole end and includes an internally threaded portion. The collar 71 is attached to the ratchet sleeve 51 by shear screw 67.
Disposed about the inner mandrel 9 and the ratchet sleeve 51 below the collar are the elements 73. The elements 73 are comprised of any suitable material, for example rubber, which, when compressed, will expand outwardly into tight engagement with the tubing wall. In FIG. 1, the plug 1 includes two elements 73 separated by a spacer 75. These are shown in more detail in FIGS. 6 and 7.
The element seat 77 is shown in FIG. 8 and is beneath the lower element and disposed slidably about the inner mandrel 9 and the ratchet sleeve 5 1. The element seat 77 provides a base for the element 73. It has an internally threaded portion at its downhole end for engaging the threaded portion of the uphole end of the upper cone 27.
The rubber mandrel 79 is disposed about the ratchet sleeve 51 and positioned longitudinally between the ratchet sleeve 51 and the collar 71, elements 73, spacer 75, element seat 77, and uphole end of the upper cone 27. It is shown in FIG. 9. It has uphole and downhole threaded portions. The uphole threaded portion engages the internally threaded portion of the collar 71. The downhole threaded portion engages the ratchet 53. At the downhole portion of the rubber mandrel is a series of stepped indentations 72. When the bridge plug is inserted into the well bore, the stepped indentations 72 are positioned above the lower threaded portion of the element seat 77 at the shear screw 81. The shear screw 81 attaches the element seat 77 to the rubber mandrel
The anchoring system is located near the downhole end of the plug 1. It includes the upper 27 and lower cones 31, and slip cage 35 already described. It also includes slips 83 shown in FIG. 12. The slips 83 are mounted on the portion 63 of the ratchet sleeve 51 and biased inwardly by slip springs. In an anchored position, the slips 83 extend outwardly through the windows 37 in the slip cage 35. The slips 83 have an outer surface 85 for engaging the tubing wall in a set position. The outer surface may be serrated or utilize other means to maintain a solid anchor on the tubing wall. The inner surface of the slips 83 includes two sloped surfaces 87,89. These sloped surfaces 87,89 correspond to the outer sloped surfaces 29,33 of the upper 27 and lower cones 31.
SETTING STAGE
To set the bridge plug 1 in engagement with the tubing wall, a setting tool is used. The setting tool may include an electric wireline setting assembly, solid wireline setting assembly, or a hydraulic setting assembly, however, any suitable tool known in the art may be used.
Before the bridge plug is inserted into the well bore, the setting tool attaches to the bridge plug 1 by threadedly engaging the shear stud 3 at its uphole end U. A sleeve on the setting tool extends over the uphole portion of the plug 1 and contacts the uphole portion of the collar 71. The setting tool and the plug 1 are run into the well bore and lowered to the desired depth to be set. The plug is preferably set using an electric or hydraulic charge.
The setting tool sleeve uses pressure to force the collar 71 downwards. At the same time, the shear stud 3 remains attached to the setting tool and, since the inner mandrel 9 is attached to the shear stud, the mandrel 9 remains relatively stationary along with the ratchet sleeve.
As the collar 71 is forced downwards, the shear pin 21 is sheared allowing the collar 71 to move in a downward direction. This force causes other downhole components such as the elements 73, element seat 77, and upper cone 27 to move downwards as well. When sufficient force is applied, preferably after the anchoring mechanism is set, the shear screw 81 also shears.
As the upper cone 27 moves downwards, the sloped surface 29 on its downhole end engages the sloped surface 87 on the slips 83. At the same time, the slips 83 are forced downward and the sloped surface 89 on the slips 83 engages the sloped surface 33 of the lower cone 31. In this manner, the slips 83 are forced outwards and into tight anchoring engagement with the tubing wall. As the pressure from the setting tool increases, the slips 83 are forced into tighter engagement with the tubing wall to provide a solid anchor for the plug 1.
As the anchoring mechanism is setting or immediately thereafter, the sealing mechanism also sets. When the anchoring mechanism is set, shear screw 81 shears. The collar 71 is connected by threaded engagement to the rubber mandrel 79. The downward movement of the collar 71 causes a downward force on the rubber mandrel 79 moving it downward. The downhole end of the rubber mandrel 79 is connected to ratchet 53 which will correspondingly move in a downward direction along the ratchet sleeve 51 causing the stepped portions 72 of the rubber mandrel to move below the position of the shear screw 81 as the rubber mandrel 79 is displaced. The force of the setting tool will compress the elements 73 forcing them to expand outwardly into sealing engagement with the tubing wall. As the pressure on the collar 71 increases and the ratchet pulls the rubber mandrel 79 in a downwards direction, the elements 73 will form a tighter seal against the tubing wall.
When the pressure reaches a predetermined level, the shear stud 3 will shear at the annular groove 7 thereby releasing the bridge plug 1 from the setting tool. The ratchet 53 will maintain the rubber mandrel 79 in its downward position drawing the collar downward and compressing the elements 73 forcing them outwards to maintain their engagement with the tubing wall. The position of the ratchet 53 and the rubber mandrel 79 also maintains the downward position of the upper cone 27 forcing the slips 73 into anchoring engagement with the tubing wall. The setting tool may now be removed from the well bore and the bridge plug 1 remains in the well bore in sealed and anchored engagement with the tubing wall.
The pressures at which the shear screws, pins and shear studs shear is predetermined and can be altered by varying the strength of these components. For example, it is preferred that shear screw 69 shears at approximately 1000 lb of pressure. Screw 81 will shear at approximately 6000 lb of pressure. The pressure created by the setting tool may reach as high as 18000 lb of pressure. At that point, the shear stud will shear releasing the plug from the setting tool. However, the strength of these components may be altered to allow them to shear at any desired pressure load.
RETRIEVING STAGE
To retrieve the plug from a well bore, a retrieving tool is used. Any suitable retrieving tool known in the art may be used. The tool may be run downhole on a wireline, tubing, or other manner known in the art.
The releasing tool slides over the uphole end of the set plug 1 and contacts the bypass valve housing 19. The tool forces the housing 19 downwards. This force causes the shear pin 21 to shear allowing the housing 19 to move downwards. This movement will allow the opening 23 in the housing 19 to line up with opening 66 in the ratchet sleeve 51. The opening 66 in the ratchet sleeve 51 connects to an opening extending between the inner mandrel 9 and the ratchet sleeve 51 along the longitudinal length to the downhole end of the plug 1. This passage and opening 23 allows gas and/or liquid to pass from the sections of the tubing above and below the set bridge plug to equalize the pressure. The plug 1 remains set in the well bore. This release of pressure will clear any debris from around the plug 1 and will allow the plug 1 to be safely removed from the well bore.
Once the pressure has been equalized, the retrieving tool will connect to the latch 13 and move it in an upwards direction. Shear pin 17 will shear allowing the latch to move upwards. Once the latch 13 has moved upwards past the uphole end of the collets 55 on the ratchet sleeve 51, the stops 59 on the collets 55 are released from the seat 12 on the inner mandrel 9. The ratchet sleeve 51 is no longer held in position in relation to the inner mandrel 9 and it will move downwards. As the ratchet sleeve 51 moves downwards, the downward pressure on the rubber mandrel 79 is relieved and the elements 73 will retract from the tubing wall to return to their relaxed position. The sealing mechanism is now released.
At the same time or immediately thereafter, as the ratchet sleeve 51 moves in a downward position, the stops 61 on the downhole end of the collets 57 also move in a downward direction. The stops 61 will move downhole of the bottom sleeve and allow the lower stops 47 to be released from the collet stops 61. This movement allows the lower cone 31 to move downwards disengaging its sloped surface 33 from the sloped surface 89 of the slips 83. The slips 83 will move downwards with the ratchet sleeve 51 and therefore their uphole sloped surface 87 will disengage the sloped surface 29 of the upper cone 27. The slip springs will bias the slips towards the ratchet sleeve 51 and into a retracted position away from the tubing wall. The anchoring mechanism is now released and the bridge plug can be raised out of the well bore.
The above-described embodiments of the present invention are meant to be illustrative of preferred embodiments and are not intended to limit the scope of the present invention. Variations of the invention will be readily apparent to persons skilled in the art and may be made without departing from the spirit or scope of the invention. These variations are intended to be within the scope of the present invention. The only limitations to the scope of the present invention are set out in the following appended claims.
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The present invention provides a bridge plug for use in a well bore for engagement with the wall of a tubing extending down the bore. The bridge plug includes a sealing and an anchoring mechanism slidably disposed on a mandrel. The sealing mechanism includes sealing elements which are expandable radially outwardly to engage the tubing wall when the elements are compressed. The anchoring mechanism includes first and second sleeves axially movable relative to one another and having radially inwardly sloped first and second ramps respectively. The ramps define a recess therebetween and slips having complementary ramps are received into the recess. The first and second ramps cooperate to force the anchoring member radially outwardly into engagement with the tubing wall upon axial movement of said first ramp towards said second ramp. The plug also includes a ratchet for locking the sealing mechanism and the anchoring mechanism in engagement with the tubing wall.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates generally to a screw assembly and method for controlling tolerances related to stacking components, and more particularly to a screw assembly and method which can provide for interlocking of adjacent components, while maintaining locational tolerances such as a constant spacing between the components.
[0003] 2. Description of Related Art
[0004] Various mechanical applications involve adjacent structural components, some of which may be in contact with one another, and others which may instead be spaced apart from one another. In some situations where adjacent structural components are spaced apart, tight locational tolerances may play a significant role in performance or effectiveness of the particular application. That is, maintaining a particular spacing between components in some systems or applications may be important to the functionality of the system.
[0005] In some of these applications, a particular spacing between adjacent components may be difficult to establish and maintain without slight variations, for example, minor increases or decreases in the gap or spacing size. In these cases, it may be difficult to establish a stable structural connection between components, or a desired gap or spacing may be either too large or too small to create a sturdy or effective connection using traditional methods.
[0006] One such application may be in the field of phased array antennas, which have seen an increase in the range of application in recent years in fields such as the defense market, including applications in communications and radar systems, as well as in various other commercial markets. For example, a phased array antenna developed by the Raytheon company, may include a radiator having a plurality of transmit/receive integrated microwave module (TRIMM) plates or columns arranged in a column assembly, and a plurality of radiating elements extending from each of the columns in the column assembly. Polarization of such a phased array antenna depends on, for example, the orientation or the alignment of the electric field radiated by the phased array antenna. A particular array orientation generates a fixed electric field alignment across all the elements of the assembly, and as such, small variations in spacing between the columns in the column assembly may have a large impact on the effectiveness, stability, and/or optimization of certain performance characteristics of the phased array antenna. Therefore, positional precision is more important for certain portions of such column assemblies, for example, the radiating elements.
[0007] In these phased array antennas, if adjacent plates or columns are stacked to contact one another, the relative positioning between radiating elements may be affected by manufacturing variations in the plates or columns, for example, variations or inconsistencies in plate thicknesses. Furthermore, in such column assemblies, as the number of columns in the column assemblies increases, any plate inconsistencies may cause additional deviations from a desired spacing between the radiating elements, as error may be compounded based on the increased number of columns, and performance degradation of the antenna as a whole may further be magnified. As such, it may be desirable to provide a certain amount of clearance between adjacent plates, in order to eliminate or reduce spacing inconsistencies between the radiating elements that may be caused by manufacturing variations of the columns. In such arrangements, the columns can therefore be aligned according to positioning of the radiating elements, and the plates may then be secured in the desired positions to eliminate or reduce such variations.
SUMMARY OF THE INVENTION
[0008] Embodiments of the present invention provide a screw assembly and method for more effectively controlling tolerances related to stacking and interlocking components.
[0009] According to aspects of an embodiment of the present invention, a screw assembly for maintaining a substantially constant gap between adjacent components includes a first screw including: an exterior surface including a first threaded surface; and an inner wall defining a bore, the bore being coaxial with a longitudinal axis of the first screw, the inner wall including a second threaded surface, wherein one of the first threaded surface or the second threaded surface is arranged with a right-hand thread, and the other one of the first threaded surface or the second threaded surface is arranged with a left-hand thread.
[0010] The first screw may have a first end and a second end, and may further have a head portion positioned at the first end adjacent to the first threaded surface, wherein the bore has an opening at the first end on the head portion and extends towards the second end. The head portion may be substantially cylindrical. The opening may include a countersink.
[0011] At least one of the first threaded surface or the second threaded surface may include a flange portion.
[0012] The screw assembly may further include a second screw including: a shaft portion including a threaded surface; and a head portion positioned on one end of the shaft portion, wherein an outer diameter of the shaft portion corresponds to the an inner diameter of the bore of the first screw and the threaded surface of the second screw is arranged with a thread that corresponds to the thread of the second threaded surface of the first screw, and wherein an outer diameter of the head portion is greater than or equal to the outer diameter of the shaft portion.
[0013] The second screw may have a first end and a second end, wherein the head portion is positioned on the first end, and wherein a friction device is arranged on the shaft portion adjacent or near the second end.
[0014] The screw assembly may further include a first component and a second component, wherein the first screw is positioned in the first component and the second screw is positioned in the second component, and wherein the first screw and the second screw are configured to engage. The second screw may be configured to advance into the bore of the first screw when rotated in a first direction, and the first screw may be configured to advance out of a bore of the first component when rotated in the first direction. In an initial position the first screw may be positioned in a first bore of the first component and the second screw may be positioned in a second bore of the second component, and in a clamped position, the first screw and the second screw may be engaged such that an end of the first screw abuts the second component to prevent movement of the second component towards the first component, and the head portion of the second screw abuts the second component to prevent movement of the second component away from the first component.
[0015] According to aspects of another embodiment of the present invention, a method for maintaining a substantially constant gap between a first component and a second component includes: inserting a first screw into a bore of the first component, the first screw including an exterior threaded surface having a left-hand thread corresponding to a threaded surface of the bore of the first component, and an inner wall defining a bore and including a second threaded surface having a right-hand thread; aligning the second component to be adjacent to and separated by a gap from the first component, wherein a bore of the second component is substantially aligned with the bore of the first component; inserting a second screw into the bore of the second component and towards the first component, the second screw including a threaded surface having a right-hand thread corresponding to the second threaded surface of the first screw, and a head adjacent to the threaded surface; rotating the second screw in a clockwise direction to engage with the first screw; further rotating the second screw in the clockwise direction, wherein the second screw rotates the first screw in the clockwise direction and advances the first screw towards the second component until the first screw contacts a first surface of the second component; further rotating the second screw in the clockwise direction to advance the second screw into the bore of the first screw, until the head of the second screw contacts a second surface of the second component opposite the first surface.
[0016] An alignment device may align the second component with the first component and to maintain the gap.
[0017] The method may further include connecting the first component and the second component with at least a third screw spaced apart from the first screw and the second screw.
[0018] A third screw configured to be substantially the same shape as the first screw may be inserted into the second component, and a fourth screw configured to be substantially the same shape as the second screw may be inserted into a third component, wherein the third screw and the fourth screw engage and clamp the second component and the third component together while maintaining a substantially constant gap corresponding to the substantially constant gap between the first component and the second component.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The accompanying drawings, together with the specification, illustrate exemplary embodiments of the present invention, and, together with the description, serve to explain the principles of the present invention, of which:
[0020] FIG. 1 shows an exploded perspective view of a portion of a column assembly of a phased array antenna in accordance with an embodiment of the present invention;
[0021] FIG. 2 schematically illustrates a top view of a column assembly of a phased array antenna in accordance with an embodiment of the present invention;
[0022] FIG. 3 shows a perspective view of a screw assembly in accordance with an embodiment of the present invention;
[0023] FIGS. 4A and 4B illustrate a side view and a cross-sectional view of a set screw from the screw assembly of FIG. 3 ;
[0024] FIG. 5 illustrates a side view of a screw from the screw assembly of FIG. 3 ;
[0025] FIGS. 6A-6D illustrate a method of interlocking adjacent components using a screw assembly in accordance with an embodiment of the present invention; and
[0026] FIG. 7 is a block diagram showing a method of interlocking adjacent components using a screw assembly in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0027] Hereinafter, certain exemplary embodiments according to the present invention will be described with reference to the accompanying drawings. Some of the elements that are not essential to the complete understanding of the present invention are omitted for clarity. In addition, similar elements that appear in different drawings may be referred to by using the same or similar reference numerals.
[0028] FIG. 1 is an exploded perspective view of a portion of a column assembly of a phased array antenna in accordance with an embodiment of the present invention, and FIG. 2 is a schematic illustration of a top view of an assembled column assembly of a phased array antenna in accordance with an embodiment of the present invention. Phased array antennas having column assemblies similar to the column assemblies 101 illustrated in FIGS. 1 and 2 have been developed by the Raytheon company, and include a plurality of TRIMM plates or columns 111 , which may be arranged adjacent to each other and spaced apart from one another. Each of the plates or columns 111 may include a plurality of supports 113 for inserting or installing radiating elements associated with the phased array antenna. Other elements may be associated with the phased array antennas, for example, feeds for electrically connecting the plates or columns 111 , and interconnecting elements 115 for holding the plates or columns 111 together and/or spaced apart at a substantially constant distance from one another.
[0029] In a phased array antenna such as the one described above, polarization of the antenna depends on the orientation and/or alignment of the electric field radiated by the elements of the phased array antenna. This, in turn, may depend on, for example, a spacing between the plates and/or their associated radiating elements, the electrical and/or mechanical intercommunication between the various elements, and/or the shape of the radiating elements. For example, in the phased array antenna of FIGS. 1 and 2 , when the column assembly 101 is in an assembled state, gaps 201 may exist between adjacent columns 111 . Such gaps may be used, for example, to provide clearance for feeds located between the columns which electrically connect the columns and their associated radiating elements and/or other elements that are positioned between the columns, or for example, to provide an exact spacing to accomplish a desired alignment between said radiating elements. Since accurate alignment of the radiating elements, rather than of the columns, is typically desirable, the gaps 201 may also serve to reduce or eliminate variations in the spacing of the radiating elements from, for example, inconsistencies or discrepancies between the thickness of the columns 111 due to, for example, manufacturing variances. Therefore, the gaps 201 can insure a more accurate spacing of the radiating elements, independent of the actual shapes or spacing between the columns 111 themselves. Additionally, the gaps 201 may exist between adjacent columns 111 , for example, to improve electrical communication between columns across the feeds, and to discourage potential cross-talk between other portions or elements of the columns themselves.
[0030] After installation of a particular phased array antenna, arrangement of the antenna elements will result in a fixed electric field alignment across all the elements of the array assembly. As such, small variations in spacing between the columns in the column assembly will affect the fixed electric field. Furthermore, as the number of plates or columns 111 in a column assembly increases, any variations exhibited between any two of the columns 111 in an assembly may be compounded and magnified across the entire column assembly, having a large and potentially debilitating impact on the effectiveness, stability, and/or optimization of certain performance characteristics of the phased array antenna. Accordingly, an accurate positioning between the radiating elements of adjacent columns becomes even more significant.
[0031] Therefore, in an application such as the phased array antenna described above, it may be desirable to implement a screw assembly which can maintain a desired or predetermined gap or distance 201 between two adjacent elements (e.g., columns 111 in the above example), such that any undesired variations between such spacing can be reduced or minimized, in order to improve performance of the system or application. Furthermore, with an adjustable screw assembly, variations in the gaps 201 between the columns 111 themselves can be more readily navigated, such that the screw assembly can be adjusted to bridge a wide range of distances between adjacent columns 111 , and then effectively maintain a particular distance. While the above system serves as an example in which embodiments of the present invention can be applied, it is to be understood that the application of the embodiments of the present invention should not be limited to the above system, and that the present invention can be applied to various other applications in which it may be desirable, for example, to maintain and effectively control tolerances associated with a preferred spacing between adjacent stacked elements.
[0032] Description of a screw assembly including set screw 301 and screw 311 in accordance with an embodiment of the invention will be described herein, with reference to FIGS. 3-5 . FIG. 3 shows a perspective view of a screw assembly in accordance with an embodiment of the present invention. Referring to FIG. 3 , an embodiment of the screw assembly includes a set screw 301 and a screw 311 . FIG. 4A illustrates a side view of a set screw, for example, the set screw 301 from FIG. 3 , while FIG. 4B illustrates a cross-sectional view of a set screw, for example, the set screw 301 from FIG. 3 , in accordance with an embodiment of the present invention. Meanwhile, FIG. 5 illustrates a side view of a screw, for example, the screw 311 from FIG. 3 , in accordance with an embodiment of the present invention.
[0033] Referring to FIGS. 3 , 4 A, and 4 B, set screw 301 includes a threaded shaft 303 . In some embodiments, such as in the illustrated embodiments, the set screw 301 may include a substantially cylindrical head region 305 on one end of the shaft 303 . In some embodiments, the head region 305 may have a diameter that is substantially equal to or larger than a diameter of the threaded shaft 303 . In these embodiments, the substantially cylindrical head region 305 may have a substantially smooth exterior. The set screw 301 may also include a threaded bore 307 that is arranged to be substantially coaxial with a longitudinal axis of the set screw 301 . The threaded bore 307 may extend along an entire length of the set screw 301 , including the threaded shaft portion 303 , as well as the head portion 305 in embodiments which include such a head portion. As such, the threaded bore 307 may include openings on opposite ends of the set screw 301 . In some embodiments, the threaded bore 307 may include a countersink approximate at least one of the openings (e.g., as seen near the opening on the head portion 305 in FIGS. 3 and 4B ). The countersink may promote or facilitate alignment and mating of the screw 311 upon insertion of the screw 311 into the bore 307 of the set screw 301 .
[0034] In embodiments of the present invention, the set screw 301 may be configured such that the thread on threaded shaft 303 is arranged to be threaded in a different direction than the thread on the threaded bore 307 . That is, in embodiments where the threaded shaft 303 on the outside of set screw 301 is a left-hand thread, the threaded bore 307 on the inside of set screw 301 will be arranged to have a right-hand thread. Correspondingly, in the above-described embodiment, the screw 311 is configured to have its own threaded shaft portion 313 which is threaded with a right-hand thread and sized to correspond to the threaded bore 307 of the set screw 301 . That is, the threaded shaft 303 of set screw 301 and the threaded shaft 313 of screw 311 will be arranged in opposite directions.
[0035] Referring to FIGS. 3 and 5 , in addition to the threaded shaft 313 , the screw 311 may also include a head portion 315 . The head portion 315 may also be substantially cylindrical and have a diameter that is greater than or equal to a diameter of the threaded shaft 313 of screw 311 . Generally, a maximum diameter of screw 311 will be equal to or smaller than a maximum diameter of the set screw 301 . The head portion 315 of screw 311 may include one of a number of different interfaces for rotation or advancement of the screw 311 . The interface of screw 311 illustrated in FIG. 3 is illustrated in the form of a hexagonal socket 317 , but in other embodiments, the interface may be, for example, a flathead socket, a Philips socket, or various other types of interfaces. The structure of the screw 311 is generally solid, and screw 311 typically will not have a bore similar to the bore 307 implemented into set screw 301 . Furthermore, the screw 311 may also include a friction device 319 on threaded shaft 313 , for increasing friction with the set screw 301 upon engagement with the set screw 301 . The friction device 319 may be one of a variety of different devices which may cause friction upon contact with threaded bore 307 of set screw 301 , for example, a fastener coating such as Nylok, or for example, a change or inconsistency in the threads of the threaded shaft 313 . Various other types of friction devices 319 may also be applied to screw 311 , and as such, friction device 319 is schematically illustrated in FIG. 5 as a block.
[0036] Operation of the screw assembly will now be described, with reference to FIGS. 6A-6D and 7 . FIGS. 6A-6D illustrate steps for a method of interlocking adjacent components using a screw assembly in accordance with an embodiment of the present invention, including cross-sectional views of two adjacent housings and incorporation of a screw with a set screw of a screw assembly. FIG. 7 is a corresponding block diagram showing a method of interlocking adjacent components using a screw assembly in accordance with an embodiment of the present invention.
[0037] Referring to FIG. 7 , in block 701 , a set screw is inserted and screwed into a threaded bore of a first housing. An example is illustrated in FIG. 6A , where set screw 301 is inserted into a threaded bore 603 of a first housing 601 . First housing 601 may be one of two adjacent plates, for example, plates similar to plates 111 as described with reference to FIGS. 1 and 2 , or may be any of various other types of components or housings. Bore 603 is threaded to correspond to threaded shaft 303 of set screw 301 . In some embodiments, set screw 301 may be inserted into bore 603 during manufacture of housing 601 . In other embodiments, set screw 301 may be inserted into bore 603 just prior to installation of the screw assembly to hold two adjacent housings together. In embodiments where threaded shaft 303 of set screw 301 is a left hand-thread, screwing-in of set screw 301 into housing 601 involves counter-clockwise rotation of set screw 301 .
[0038] In block 703 , the first housing 601 is aligned with a second housing 611 , as also illustrated in FIG. 6A . The first housing 601 and the second housing 611 may be aligned and held, such that a preferred gap or distance separates them, as described with reference to FIGS. 1 and 2 . Maintaining of a constant desired distance may be achieved, for example, by an alignment jig that maintains the distance between two adjacent housings during assembly of the column assembly. In other embodiments, various other structures and methods may be used to hold adjacent plates or housings together prior to installation of the screw assemblies. Furthermore, in some embodiments, the bores 603 of housings 601 may be below or outside a visual surface of the housing 601 , such that when an adjacent housing 611 is positioned at a desired spacing from housing 601 , the set screws 301 that were inserted in housing 601 may be concealed from view.
[0039] In block 705 , a screw 311 is inserted into a bore 613 of the second housing 611 , which is sized to correspond to the threaded shaft 313 of screw 311 . Referring to FIG. 6A , insertion of screw 311 into bore 613 of housing 611 advances screw 311 towards set screw 301 . In some embodiments, bore 613 of second housing 611 may be threaded, with a right-hand thread to correspond to threaded shaft 313 of screw 311 . In other embodiments, bore 613 may not be threaded, and may be sized, for example, to be slightly larger than a largest diameter of the threaded shaft 313 of screw 311 , such that screw 311 can freely move in bore 613 .
[0040] In block 707 , the screw is rotated in a first direction with, for example, a screwing-in tool corresponding to an interface or socket on the screw, to engage the screw with the set screw. In these embodiments, bore 613 of housing 611 will be substantially aligned with bore 603 of first housing 601 . Referring to previously described embodiments where the threaded shaft 311 of screw 313 is a right-hand thread, upon contact of screw 311 with set screw 301 , clockwise rotation of screw 311 will cause screw 311 to engage set screw 301 and advance a first distance into bore 307 of set screw 301 , for example, as illustrated in FIG. 6B . In the previously described embodiments in which set screw 301 is out of view after alignment of housings 601 and 611 , engagement of screw 311 with set screw 301 may further be facilitated by a countersink at the opening of bore 307 of set screw 301 as previously described. In these embodiments of the present invention, blind access and adjustment control of the screw assembly can be achieved, such that engagement and adjustment of the screw assembly can be accomplished while the set screw 301 and the interface between set screw 301 and screw 311 are out of view.
[0041] As previously discussed, in some embodiments, at least a portion of threaded shaft 313 of screw 311 and/or approximate bore 307 of set screw 301 may be coated with, for example, Nylok, or any of various other fastener coatings or compounds which may serve to increase a frictional force between the surfaces of threaded shaft 313 of screw 311 and threaded bore 307 of set screw 301 . Friction may alternatively be established, for example, by a manipulation or variation in the thread or thread spacing of either the threaded shaft 313 of screw 311 or the threaded bore 307 of set screw 301 , or by any of various other friction devices 319 . This may induce, for example, a temporary hold between screw 311 and set screw 301 , such that continued rotation of the screw 311 will also result in corresponding rotation of the set screw 301 .
[0042] In block 709 , rotation of screw 311 continues in a same direction as the rotation in block 707 . That is, in previously described embodiments, since screw 311 was rotated in a clockwise direction, rotation of screw 311 continues in the clockwise direction in block 709 . Conversely, in embodiments in which screw 311 is rotated in a counter-clockwise direction in block 707 , continued rotation of screw 311 in the counter-clockwise direction would occur in block 709 . Due to the friction between screw 311 and set screw 301 caused by, for example, the friction device 319 on screw 311 or set screw 301 as described in reference to block 707 , continued rotation of screw 311 will also cause a corresponding rotation of set screw 301 . As described above with respect to FIGS. 1 , 2 , and 6 A, in embodiments where threaded shaft 313 of screw 311 is a right-hand thread, threaded shaft 303 of set screw 301 will conversely be a left-hand thread. Therefore, rotation of set screw 311 in a clockwise direction will cause the screw 311 /set screw 301 combination to advance away from first housing 601 , such that set screw 301 begins to rotate out of bore 603 of first housing 601 and towards a surface 615 of second housing 611 that faces first housing 601 , as seen in FIG. 6C . Continued rotation of the screw 311 /set screw 301 combination in the clockwise direction will eventually result in substantially cylindrical head portion 305 of set screw 301 contacting or abutting against the surface 615 of the second housing 611 . Upon contact of the head portion 305 of set screw 301 against the surface 615 of the second housing 611 , advancement of the set screw 301 away from the first housing 601 stops. At this point, a substantially fixed positioning is established between the first housing 601 and the set screw 301 , such that and end of the set screw 301 nearest to the second housing 611 serves as an abutment or support for maintaining a minimum distance or gap between the first housing 601 and the second housing 611 .
[0043] In block 711 , after abutment of set screw 301 against surface 615 , rotation of screw 311 is further continued in the same direction as rotation in blocks 707 and 709 . Therefore, in the embodiments previously described, rotation of set screw 311 continues on a clockwise direction. Here, a force of the second housing 611 pushing against the set screw 301 and preventing further advancement of the set screw 301 away from the first housing 601 is generally greater than a force holding the screw 311 and set screw 301 together, for example, by the friction device 319 as previously described. Furthermore, since the distance between the first housing 601 and the second housing 611 may be additionally fixed or supported by, for example, an alignment jig in some embodiments, such additional support may also deter or prevent further movement of the set screw 301 away from the first housing 601 .
[0044] Accordingly, after abutment of head portion 305 of set screw 301 with surface 615 of the second housing 611 , the abutment causes release of the temporary hold between screw 311 and set screw 301 (e.g., from the friction device 319 ), such that screw 311 may thereafter freely rotate independent of set screw 301 . As described above, at this point, set screw 301 is deterred from further advancement away from the first housing 601 and maintains a minimum distance or gap between first housing 601 and second housing 611 . After release of the temporary hold between screw 311 and set screw 301 , the continued clockwise rotation of screw 311 therefore advances screw 311 further into bore 307 of set screw 301 , as seen in FIG. 6D . Rotation of screw 311 is continued until a side of head portion 315 of screw 311 comes into contact with a second side or face 617 of the second housing 611 adjacent to the bore 613 . In other words, screw 311 may be advanced into set screw 301 until screw 311 has been tightened against side 617 of the second housing 611 .
[0045] Such a tightened configuration, as illustrated in FIG. 6D , can be viewed as a clamped position, where the distance between the first housing 601 and the second housing 611 has been substantially fixed, such that the head portion 305 of the set screw 301 substantially prevents movement of the second housing 611 any closer to the first housing 601 , while the head portion 315 of the screw 311 substantially prevents movement of the second housing any further away from the first housing 601 . As such, a desired or preferred gap between the first housing 601 and the second housing 611 can be maintained. Thereafter, in embodiments where an alignment jig or other device or mechanism was utilized to hold the housings together during application of the screw assembly, said device or mechanism can be removed.
[0046] In embodiments where multiple adjacent columns or components are stacked, implementation of the screw assembly or assemblies can be sequentially performed, such that after two adjacent components have been clamped together, a third component can then be clamped to one of the two adjacent components, and a fourth component can then be clamped to the third component, etc. Such assembly can continue until the desired number of components have been stacked and clamped together, such that a constant column to column tolerance gap can be achieved and maintained. As discussed above, it is generally understood that, as the number of components or elements in a particular assembly increases, the gap variations and tolerances between each pair of adjacent components causes the total variance in the assembly to increase and get compounded. Where performance of a particular application is dependent on, for example, an exact spacing between components, such as with respect to column assemblies for phased array antennas as described above, the screw assemblies in accordance with aspects of the present invention can reduce or minimize errors or variations associated with the gaps between adjacent components, such that a significant number of additional components may be added to the stack, while maintaining the desired tolerance control, such that performance of the phased array antennas can be improved.
[0047] In embodiments of the present invention, a screw assembly can be utilized to stack components and to control tolerances associated with maintaining a preferred distance or gap between adjacent components in a stack. By utilizing an adjustable screw assembly according to embodiments of the present invention, components may be held at a desired distance, independent of and irrespective of manufacturing tolerances of the components themselves. Such a screw assembly may also be beneficial, for example, where a desired gap between components may be too great to maintain and keep substantially constant when no additional structural connections are implemented. Furthermore, in certain applications, the additional structural tie between components provided by the screw assemblies according to embodiments of the present invention may improve the stability of column assemblies or other structures, and to help them meet certain performance characteristics, such as tactical vibration requirements.
[0048] In some embodiments, the assemblies described above may be modified, or additional features may be added to or supplement the assemblies, without departing from the spirit or scope of the present invention. For example, in some embodiments, flanges may be used on one or more of the screw elements instead of screw threads. In other embodiments the screw assemblies may further be supplemented by regular screw elements positioned at other portions of adjacent components. In such embodiments, the screw assemblies according to an embodiment of the present invention may first be installed to maintain a particular distance or gap between adjacent components, and regular screw elements may then be installed to provide additional structural support between the adjacent components after the desired gap has been established.
[0049] While the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, and equivalents thereof.
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A screw assembly for maintaining a substantially constant gap between adjacent components includes a first screw including: an exterior surface including a first threaded surface; and an inner wall defining a bore, the bore being coaxial with a longitudinal axis of the first screw, the inner wall including a second threaded surface, wherein one of the first threaded surface or the second threaded surface is arranged with a right-hand thread, and the other one of the first threaded surface or the second threaded surface is arranged with a left-hand thread.
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FIELD OF THE INVENTION
[0001] The present invention relates to an iron holder, more particularly to an iron holder with an insulation board.
BACKGROUND OF THE INVENTION
[0002] An iron holder typically includes a base and an insulation board for supporting the iron and insulating heat. The insulation board of a traditional iron holder is fixed on the base in a special angle and position, and can not be moved or revolved. An iron, after being used, it cannot be conveniently to place the iron on the insulation board.
SUMMARY OF THE INVENTION
[0003] The primary object of the present is to provide an iron holder to obviate the disadvantages of the traditional irons that the insulation board is fixed on the base and can not be moved or revolved.
[0004] This and other objects of the present invention are achieved by providing:
an iron holder which comprises a base and an insulation board for supporting the iron, the base forming a revolvable relationship with the insulation board, and an angle adjusting unit arranged between the insulation board and the base for adjusting the revolving angle of the insulation board revolving relative to the base.
[0006] In one preferred embodiment of the present invention, the insulation board pivotally connected with the base, the angle adjusting unit comprising:
a sliding device formed sliding-connection relationship with the insulation board; and a step stool fixed on the base, and the step stool has at least a step, the said sliding device abuts against one step of the step stool.
[0009] In one preferred embodiment of the present invention, the side of the insulation board has a sliding track, the sliding device slidingly connected with the sliding track.
[0010] In one preferred embodiment of the present invention, there is a lock unit arranged between the sliding track and the sliding device for locking or releasing the sliding device relative to the sliding track.
[0011] In one preferred embodiment of the present invention, the lower portion of the sliding device has an abutting portion extending below the insulation board, the abutting portion abuts against one step of the step stool.
[0012] In one preferred embodiment of the present invention, the step stool has four steps.
[0013] In one preferred embodiment of the present invention, there are two lugs arranged on the lower portion of the insulation board, each lug has a revolving seat, the base has a coupler, the revolving seat pivotally connected with the coupler; the angle adjusting unit comprising:
an adjusting board fixed on the base, and the adjusting board has at least a lock hole, the at least a lock hole formed an arc whose center is on the shaft between the insulation board and the base; and a compress portion comprising a sleeve fixed on the lug, an elastomer in the sleeve and a ball abuts against the inner end of the elastomer, the inner terminal of the ball positioned in the at least a lock hole, and the diameter of the ball is larger than the diameter of the lock hole.
[0016] In one preferred embodiment of the present invention, the compress portion further comprises an adjusting screw which threads through the lug from the outside into the inner side, and the inner end of the screw connects with the out end of the elastomer.
[0017] In one preferred embodiment of the present invention, the adjusting board has six lock holes.
[0018] In one preferred embodiment of the present invention, the base has a groove for containing the insulation board when the insulation board is in the lowest position.
[0019] In one preferred embodiment of the present invention, the adjusting unit comprising:
a connecting penetration hole having at least a transverse recess portion in the inner side; a push button, its end being through the penetration hole from the out side into inner side; an elastomer connecting with the inner side of the push button, it sheaths the push button; and a block with a transverse protrusion, the head of the block connects to the end of the push button; normally the transverse protrusion of the block inserted in the transverse recess portion of the penetration hole by the action of the elastomer; if the push button is pressed, the push button will push the block back transversely, then the transverse protrusion of the push button disengaged from the transverse recess portion of the penetration portion.
[0024] In one preferred embodiment of the present invention, the base pivotally connected with the insulation board via a sleeve axis, the angle adjusting unit comprising at least:
a slider connecting slidingly with the sleeve on the shaft direction, and the side of the slider has a position protrusion; a slot arranged in the base corresponding to the position protrusion and the position protrusion can slide along the axis direction of the slot; an arc limit groove arranged on the insulation board corresponding to the position protrusion and the position protrusion can rotate limitedly in the groove; a position opening in the sleeve corresponding to the slot; and a button on the insulation board for pushing the slider from the position between the insulation board and the base to the pivotal connection portion of the base.
[0030] Because the insulation board and the base formed pivoted relationship, and the angle adjusting unit can adjust the angle between the insulation board and the base, the present invention obviated the disadvantages in the existed arts and has the advantages as follows: firstly, the insulation board can be adjusted into a preferred angle for the users to lay the iron, so the holder has more convenient operation ability; secondly, it improves the appearance of the product; thirdly, it can be conveniently stored up in packing to reduce the packing materials. The insulation board can be revolved freely from 0 degree to 90 degrees, the screw can adjust the elasticity of the elastomer and adjust the force for revolving the insulation board, thus can meet the different demands of different users.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Exemplary embodiments of the invention will be explained in more detail below with reference to the drawings, in which:
[0032] FIG. 1 is a top view of the iron holder in embodiment 1.
[0033] FIG. 2 is a side sectional view of the iron holder in embodiment 1.
[0034] FIG. 3 is a top view of the iron holder in embodiment 2.
[0035] FIG. 4 is a side sectional view of the iron holder in embodiment 2.
[0036] FIG. 5 is a partial enlarged view of the iron holder in embodiment 2.
[0037] FIG. 6 is a sectional view of A-A of FIG. 4 .
[0038] FIG. 7 is an exploded view of the coupler of the iron holder in embodiment 3.
[0039] FIG. 8 illustrates the iron holder in A 1 angle position in embodiment 3.
[0040] FIG. 9 illustrates the iron holder in A 2 angle position in embodiment 3.
[0041] FIG. 10 is an exploded view of the coupler of the iron holder in embodiment 5.
[0042] FIG. 11 is a sectional view of FIG. 10 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Embodiment 1
[0043] Referring to FIG. 1 and FIG. 2 , they show the top and sectional views of the iron holder in this embodiment respectively. An iron holder comprises a base 100 , an insulation board 200 and an angle adjusting unit 300 .
[0044] The top of the base 100 has a groove 120 , the left side and right side of the lower portion of the insulation board 200 have a pivoted portion extending outwardly respectively, the pivoted portion pivotally connected to the base 100 to form a pivoted connection relationship between the insulation board 200 and the base 100 . And the insulation board 200 will be positioned in the groove 120 when the insulation board 200 is in the lowest position.
[0045] The angle adjusting unit 300 comprises a step seat 310 , a sliding device 320 and a sliding track 330 . The sliding track 330 is fixed in the left side of the insulation board 200 . The lower portion of the sliding device 320 has an abut portion 321 extending downwardly below the insulation board 200 , and the sliding device 320 is slidingly connected on the sliding track 330 to form a sliding connection relationship between them, when appropriate, a lock unit for locking or releasing the sliding device 320 relative to the sliding track 330 can be arranged between the sliding device 320 and the sliding track 330 . The step stool 310 is fixed on the base 100 , and the step stool 310 forms four steps facing upward.
[0046] A user can slide the sliding device 320 relative to the slide track 330 , then put the abut portion 321 of the sliding device 320 against at least a step of the step stool 310 . The higher step the abut portion 321 is abut against, the bigger the angle between the insulation board 200 and base 100 is formed.
Embodiment 2
[0047] Referring to FIG. 3 to FIG. 5 , they show the top and sectional views of the iron holder in this embodiment. An iron holder comprises a base 100 , an insulation board 200 and an angle adjusting unit 300 .
[0048] The top of the base 100 has a groove 120 , the groove 120 has two inserting slots 121 in the front portion, and the base 100 has two couplers 122 . The lower portion of the insulation board 200 has two lugs 210 , each lug 210 has a revolving seat 211 . The two lugs 210 of the insulation board 200 are inserted into the two slots 121 respectively, thus the revolving seat of the insulation board 200 is pivotally connected to the coupler of the base 100 to form a revolving connection relationship between the insulation 200 and the base 100 . The insulation board 200 will be positioned in the groove 120 when the insulation board 200 is in the lowest position.
[0049] The angle adjusting unit 300 comprises an adjusting board 340 , a position sleeve 350 , an elastomer 360 , a ball 370 and an adjusting screw 380 . The adjusting board 340 fixed on the base 100 , and there are six lock holes 341 on the adjusting board 340 , these lock holes 340 arranged in an arc whose center is located on the pivotal shaft between the insulation board 200 and the base 100 , herein the diameter of each lock hole 341 is smaller than the diameter of the ball 370 . The position sleeve 350 is fixed on the lug of the insulation board 200 ; the adjusting screw 380 extends through the lug from outer into inner side; the elastomer 360 mounted in the position sleeve 350 , and its outer side connects with the inner side of the screw 380 , its inner side connects with the ball 370 to let the inner side of the ball 370 be positioned in one of the lock holes 341 .
[0050] In use, the user can revolve the insulation board 200 relative to the base 100 , thus the adjusting board 340 presses the elastomer 360 and drives the sleeve 350 revolved, after reaching a desired angle, aligning the ball 370 to one of the hole 341 , then the ball 370 will be inserted into the lock holes 341 by the action of the elastomer 360 to lock the angle between the insulation board 200 and the base 100 . The higher the position of the lock hole 341 , the bigger the angle formed between the insulation board 200 and the base 100 . In this embodiment, the angle θ between the insulation board 200 and the base 100 may be from 0 degree to 90 degrees.
[0051] The users can adjust the screw 380 to adjust the elasticity of the elastomer 360 to adjust the needed force of revolving the insulation board 200 .
Embodiment 3
[0052] An iron holder comprises a base 100 , an insulation board 200 and an angle adjusting unit 300 . the lower portion of the insulation board 200 has two lugs 210 , the base 100 has a coupler 110 .
[0053] Referring to FIG. 7 , the coupler 110 has a fixing portion 111 , a folding portion 112 and a connecting portion 113 , the fixing portion 111 and the folding portion 112 is incorporated with the connecting portion 113 , the fixing portions 111 are fixed on the left surface and right surface of the base 100 respectively, the folding portion 112 is between the fixing portion 111 and the connecting portion 113 , the outer side of the connecting 113 inwardly recessed to form an annular holding hole 114 , and there is a limit block 115 in the annular holding hole 114 .
[0054] The two lugs 210 abut against the coupler 110 in the outer side of the base 100 to form revolving relationship, herein at least an angle adjusting unit 300 is arranged between a lug 210 and its corresponding coupler 110 . The angle adjusting unit 300 comprises a push button 510 , an elastomer 520 , a block (or a push block) 530 and a penetration hole 540 .
[0055] The lug 210 of the insulation board 200 has a step-shaped penetration hole 540 with smaller size inside and larger size outside, the smaller-sized portion of the penetration hole 540 has a transverse inward recess portion.
[0056] The push button 510 is step-shaped and is corresponding to the shape of the penetration hole 540 . The push button 510 is inserted in the penetration hole 540 from the outer side to the inner side, the smaller-sized shaft of the push button 510 is corresponds to the smaller-sized portion of the penetration hole 540 , and the larger-sized shaft of the push button 510 corresponds to the larger-sized portion of the penetration hole 540 .
[0057] The tail of the block 530 is in annular shape, and there is a transverse protrusion 531 extending upwardly on the block 530 . The head of the block 530 connected to the tail of the smaller-sized shaft of the push button 510 . The tail of the block 530 can be mounted revolvably in the annular hole 114 of the coupler 110 , and the transverse protrusion 531 is cooperated with the block 115 of the annular hole 114 to form a revolvable connection relationship and the utmost revolveing angle is A 1 .
[0058] The elastomer 520 sheathed on the smaller-sized shaft of the push button 510 , one end of the elastomer 520 connected to the annular surface of the larger-sized shaft of the push button 510 , another end connected to the coupler 110 , in the action of the elastomer, the push button 510 is pressed so that its head extends out of the outer surface of the lug 210 , the transverse protrusion 531 inserted in the inward recess of the lug 210 to form a synchronized-revolve relationship between the push button 530 and lug 210 . Herein one end of the transverse inward recess of the lug 210 connecting to the inner side of the lug 210 , another end is closed; the transverse length of the inward recess is equal to the maximum moving distance of the push button 510 so that when the push button 310 be pressed entirely, the head of the block 530 is equal to the corresponding surface of the coupler 110 .
[0059] When the insulation board 200 is in covering status, the transverse protrusion 531 will insert into the transverse inward recess of the lug 210 by the action of the elastomer 520 , thus the slide 530 and the lug 210 formed synchronous revolving relationship, if the users raise the insulation board 200 , the lug 210 and the slide 530 will be revolved relative to the coupler 110 and the base 100 , when the transverse protrusion 531 of the slide 330 turned into the limit block 115 of the coupler 110 , the revolving movement of the slide 530 will be stopped, i.e. this is the utmost revolving angle for A 1 , referring to FIG. 8 , it illustrates the A 1 angle between the insulation 200 and the base 100 .
[0060] When the push button 510 be pushed, the slide 530 will move back until the head surface of the slide 530 is equal to the corresponding surface of the coupler 110 , then the transverse protrusion 531 of the slide 530 deviated from the transverse inward recess of the lug 210 , thus the slide 530 and the lug 210 formed free revolving relationship, i.e. the lug 210 can revolve relative to the slide 530 , coupler 110 and base 100 , revolve the insulation board 200 till to the angle A 2 (reffering to FIG. 9 ), A 2 is larger than A 1 .
[0061] If the insulation board 200 needed to be closed, the user only needs to revolve the insulation board directly when revolve to the A 1 angle By the action of the elastomer 360 , the transverse protrusion 531 of the slide 530 will insert into the transverse inward recess of the lug 210 , thus the slide 530 formed synchronous revolving relationship with the lug 210 again.
Embodiment 4
[0062] The difference of this embodiment to the embodiment 3 is that: the smaller-sized portion of the penetration hole 540 has multiple inward recesses, when the push button 510 be pushed, the slide piece 530 will be moved back until the head surface of the slide piece 530 is equal to the corresponding surface of the coupler 110 , then the transverse protrusion 531 of the slide piece 530 deviated from one of the transverse inward recesses of the lug 210 , thus the slide piece 530 and the lug 210 formed free revolving relationship, i.e. the lug 210 can revolve relative to the slide piece 530 , coupler 110 and base 100 , revolve the insulation board 200 till the transverse protrusion 531 of the slide piece 530 inserts into another transverse inward recess of the lug 210 again. By abovementioned method the transverse protrusion 331 of the slide piece 530 can be inserted into anyone transverse inward recess of the lug 210 , thus the angle between the base 100 and the insulation board 200 can be adjusted.
Embodiment 5
[0063] Referring to FIG. 10 and FIG. 11 , it shows the exploded view and sectional view of the coupler of the iron holder in embodiment 5 respectively. An iron holder comprises a base 100 , an insulation board 200 and an angle adjusting unit 300 . The rear portion of the side of the base 100 pivotally connected with the connecting portion 220 of the insulation board 200 according to an axis of sleeve 400 via a coupler 130 to form revolvable connection. The angle adjusting unit 300 comprises at least a slide piece 550 , a position groove 560 , an arc groove 570 , a position opening 580 and a push button 590 .
[0064] The slide piece 550 connected to the sleeve 400 along the axis direction, the wall of the slide piece 550 has a position protrusion 551 , the position groove 560 corresponding to the position protrusion 551 is arranged in the coupler 130 of the base 100 , and is for the position protrusion 551 sliding along the axis direction. There is an arc groove 570 corresponding to the position protrusion 551 in the connection portion 220 of the insulation board 200 , it is used for the position protrusion 551 revolve limitedly, the said sleeve 400 has an position opening 580 corresponding to the position groove 560 .
[0065] When the slide piece 550 sliding along the axis direction in the sleeve 400 , the position protrusion 551 will slide along the said position groove 560 and the position opening 580 , so that the slide piece 550 can slide relative to the sleeve 400 and connection portion 220 , but can not revolve relative to the sleeve 400 and connection portion 220 , and the sleeve 400 can not revolve relative to connection portion 220 . And the sleeve 400 can be positioned relative to the connection portion 220 by being locked from the lower portion of the connection portion 210 with a screw and by the cut surface 410 of the sleeve 400 , thus the sleeve 400 can not revolve or slide relative to connection portion 220 . When the slide piece 550 is between the connection portion 110 and the connection portion 220 , the position protrusion 551 will partially insert into the arc groove 570 , thus the revolving of the insulation board 200 relative to the sleeve 400 will be limited to the arc groove 570 , in this embodiment, the angle of the arc groove 570 is A 1 . When the slide piece 550 slides into the connection portion 110 totally, the position protrusion 551 is inserted into the position groove 570 totally and will not limit the insulation board 200 , so in this status, the insulation board 200 will revolve freely relative to the sleeve 400 to the utmost position A 2 .
[0066] The push button 590 arranged in the connection portion 220 of the insulation board 200 , the push button 590 can push the slide piece 550 from the position between the coupler 130 of the insulation board 200 and the connection portion 220 of the base 100 into the coupler 130 of the base 100 . The sleeve 400 inserts into the coupler 130 of the base 100 from the outside opposite to the base 100 of the connection portion 220 of the insulation board 200 , and the sleeve 400 has a flange 420 to prevent from exceeding insertion. The push button 590 includes a head 591 and a smaller-sized shaft 592 , the shaft 592 inserts into the sleeve 400 , and there is a restoration spring 593 arranged between the head 591 and the outer side of the sleeve 400 , the slide piece 550 fixed into the inner side of the shaft 592 via a screw. When the push button 590 is pressed, the slide piece 550 will totally insert into the connection portion 110 of the base 100 ; when the push button 590 be released, the slide piece 550 will be repositioned in the position between the coupler 130 of the base 100 and the connection portion 220 of the insulation board 200 by the action of the restoration spring 593 , i.e. it can achieve the switch of the two status by the push button 590 . In addition, a groove 600 formed in the outside opposite to the base 100 of the connection portion 220 of the insulation board 200 , the flange 420 of the sleeve 400 , the head 591 of the push button 590 and the spring 593 between them are all in the groove 600 and protected by the groove 600 .
[0067] Because many varying and differing embodiments may be made within the scope of the inventive concept herein taught and because many modifications may be made in the embodiment herein detailed in accordance with the descriptive requirement of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense.
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An iron holder comprises a base and an insulation board for supporting the iron, the base forming a revolvable relationship with the insulation board, and there is an angle adjusting unit is arranged between the insulation board and the base for adjusting the revolving angle of the insulation board revolving relative to the base. Because the insulation board and the base forms a pivoted relationship, and the angle adjusting unit can adjust the angle between the insulation board and the base, the insulation board can be adjusted into a preferred angle for the users to lay the iron; and the iron holder can be conveniently packed to reduce packing materials.
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BACKGROUND OF THE INVENTION
This invention relates to ABA triblock copolymers wherein the A segments are polyolefin and the B segments are polycarbonate.
Polycarbonate polymers are well known, commercially available materials having a variety of applications. Such carbonate polymers may be prepared by reacting a polyhydroxy compound, such as 2,2-bis(4-hydroxy phenol)-propane, with a carbonate precursor, such as phosgene, in the presence of an acid binding agent. Generally speaking, the polycarbonate resins have excellent physical properties, including tensile and impact strength, heat resistance and dimensional stability, are usable over wide temperature limits and have good creep resistance. However, the polycarbonates are expensive, difficult to process from a melt because of high viscosities at temperatures slightly above the melting point and exhibit severe environmental stress grazing and cracking.
In general, polycarbonates are incompatible with other polymers, particularly polymers derived from ethylenically unsaturated monomers, thereby inhibiting the use of other polymeric materials in order to modify polycarbonate compositions or to use polycarbonates as modifiers for other polymer compositions.
SUMMARY OF THE INVENTION
In accordance with the present invention, there are provided new polymeric compositions comprising polyolefin-polycarbonate-polyolefin ABA type triblock copolymers prepared by reacting a monohydroxyl terminated polyolefin with a carbonate precursor and subsequently with bisphenol A. The triblock copolymers of the invention improve the properties of polycarbonate-polyolefin blends.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the preferred embodiment, each A segment of the triblock copolymers comprises a polyolefin having a molecular weight in the range from 300 to 50,000 and the B segment comprises a polycarbonate having a molecular weight in the range of 5,000 to 30,000. The polycarbonate segment can be formed from a single polyhydroxy compound, such as polyethylene glycol or bis(4-hydroxy phenyl) propane or a mixture of two or more such polyhydroxy compounds. In the latter case, it is preferable that one of the mixture of polyhydroxy compounds is bis(4-hydroxy phenyl) propane.
In the ABA type block copolymers of this invention, each of the A units or segments comprise a polyolefin joined to the polycarbonate B segments. Thus, it is a characteristic feature of the present invention that the polyolefin contain a single reactive group and that the polycarbonate contain two groups which are reactive with the reactive moiety of the polyolefin. Preferably, the reactive moiety of the polyolefin will be a hydroxy group with the reactive functionality of the polycarbonate being obtained from a carbonate precursor compound such as a diacyl halide, a diisocyanate, a bis(haloaryl) sulfone, a carbonyl halide or bis-haloformate with carbonyl halides and bis-haloformates, particularly carbonyl halides, being preferred. The polycarbonate is derived from polyhydric alcohols or phenols, particularly dihydric alcohols or phenols, with dihydric phenols being particularly preferred.
In forming the polycarbonate B segment, there can be employed substantially any dihydroxy compounds, including their polymeric forms. Examples include the lower alkylene glycols having from 2 to 8 carbon atoms, the dihydroxy terminated polyoxyalkylene ethers having an average number of repeating units of 2 to 10 and the alkylene groups having from 2 to 8 carbon atoms, dihydric phenols of the benzene series, such as hydroquinone, resorcinol, etc., biphenols of the benzene series, e.g., dihydroxy biphenols, or bisphenols of the benzene series which are either bis(hydroxy phenyl) alkenes wherein the alkene moiety has from 1 to 8 carbon atoms or bis(hydroxy phenyl) oxides or ethers, or the above compounds which contain either a phenylene or biphenylene group wherein from 1 up to the total number of halogens on the aryl rings are replaced by alkyl groups having from 1 to 8 carbon atoms or halogen groups.
Specific examples of dihydric alcohols are alkylene glycols, such as ethylene glycol, 1,2- and 1,3-propane diol, the various isomeric butane diols, the various isomeric hexane diols, including the cyclohexane diols or dihydroxy cyclohexanes, the isomeric octane diols, the poly(oxyalkylene) glycols, such as triethylene glycol, tetraethylene glycol and the like.
Examples of phenols of the benzene series include biphenols, bisphenols and the halo and alkyl substituted derivatives thereof, hydroquinone, resorcinol, catechol, 1,2-dihydroxy-4-chlorobenzene, 1,4-dihydroxy-2chlorobenzene, 1,2-dihydroxy-4-bromobenzene, 2,5-dihydroxy3-chlorotoluene, 2,4'-dihydroxy diphenyl, 3,3',5,5'-tetrachloro-4,4'-dihydroxy diphenyl, 4,4'-dihydroxy diphenyl ether, bis(2-hydroxy phenyl) methane, 1,2-bis(4-hydroxy phenyl) methane and 1,1-bis(4-hydroxy phenyl) propane, 2,6-dihydroxy naphthalene, bis-(4-hydroxy phenyl) sulfone, 2,4-dihydroxy diphenyl sulfone, 5'-chloro-2,4'-dihydroxy diphenyl sulfone, 4,4'-dihydroxy diphenyl ether, 4,4'-dihydroxy-3,3'-dichloro diphenyl ether and 4,4'-dihydroxy-2,5-dihydroxy diphenyl ether. Currently, the preferred dihydroxy compound for use in preparing the B segment polycarbonate is 4,4-bis(hydroxy phenyl)propane, also known as bisphenol A.
The polyolefin A segments are formed from substantially any polymer, copolymer or interpolymer of alkenes having from 2 to 8 carbon atoms with the proviso that such polymers have a single terminal moiety which is reactive with the polycarbonate precursor material, such as a carbonyl halide, bis-haloformate or bis(carbonate ester). Particularly preferred are monohydroxy functional homopolymers and copolymers of ethylene. The monohydroxyfunctional polyolefins can be prepared by the catalyzed polymerization of olefins, such as ethylene, followed by hydrolysis of the aluminum-terminated polymer.
Carbonate precursor compounds suitable for use in making the triblock copolymers of this invention include diacyl halides of both aliphatic and aromatic dicarboxylic acids, diisocyanate, bis(haloaryl) sulfones, carbonyl halides, carbonyl haloformates and carbonate esters. The carbonyl halides which may be employed are carbonyl bromide, carbonyl chloride and mixtures thereof. Typical of the carbonate esters which may be employed are diphenyl carbonate, di-(halophenyl) carbonates such as di-(chloro phenyl) carbonate, di-(bromophenyl) carbonate, di-(trichlorophenyl) carbonate, di-(tribromophenyl) carbonate, etc., di-(alkylphenyl) carbonates such as di-(tolyl) carbonate, etc., di-(naphthyl) carbonate, di-(chloronaphthyl) carbonate, phenyl tolyl carbonate, chlorophenyl chloronaphthyl carbonate, or mixtures thereof. The suitable haloformates which ma be used include bis-haloformates of dihydric phenols and bis-chloroformates of dihydric alcohols such as ethylene glycol, neopentyl glycol, polyethylene glycol and the like. While other carbonate precursors will occur to those skilled in the art, carbonyl chloride, also known as phosgene, is preferred.
The triblock copolymers of this invention can be produced by conventional solution or interfacial processes known in the art for the manufacture of polycarbonates. The solution process involves reacting, for example, the monohydroxy polyolefin and carbonate precursor such as phosgene in an appropriate solvent such as methylene chloride and contacting the phosgenated-polyolefin with the dihydric phenol in the presenc of additional phosgene. The reaction mixture may be a single organic phase employing a compatible solvent such as a halohydrocarbon, e.g., trichloromethane and utilizing a base such as pyridine or triethylamine to accept the by-product hydrogen chloride. Alternatively, interfacial polymerization techniques may be employed wherein the reaction media is composed of an organic phase and an alkaline aqueous phase. A phase transfer catalyst, that is, an acid acceptor such as triethylamine or sodium hydroxide, may be used to accept the by-product hydrogen chloride from the condensation in the organic phase and to transfer the hydrogen chloride to the alkaline aqueous phase where it is neutralized and the catalyst is regenerated to its unprotonated form to accept additional hydrogen chloride.
The solution and interfacial polymerization techniques known in the art for the manufacture of carbonates can be applied equally in the practice of the instant invention, as more fully set forth in the examples.
Any conventional organic solvent that will solvate the product polymer may be used in the process of the instant invention, so long as the solvent is chemically unreactive in the polycarbonate polymerization. A preferred group of solvents is the chlorinated aliphatic hydrocarbons of 1-4 carbons such as dichloromethane, chloroform, carbon tetrachloride, dichloroethane, trichloroethane, trichloroethylene, tritetrachloroethylene and mixtures thereof. Another desirable class of solvents is the optionally halogenated aromatic hydrocarbons such as monochlorobenzene, dichlorobenzene and mixtures thereof. Preferred solvents are the chloromethanes and especially dichloromethanes. The solvents used in a solution polymerization process are preferably water free so as to avoid side reactions.
The interfacial process utilizes an organic phase and an aqueous phase. In carrying out the interfacial process, it is important that the organic solvent chosen be immiscible with water. The quantity of organic solvent and the concentration of the reactants in the solvent are not critical except that sufficient solvent should be present to dissolve the product polymer and the organic carbonate precursors such as phosgene should be present in an amount sufficient to form the polycarbonates of the present invention. An amount of organic solvent sufficient to form a product polymer solution of about 20 weight percent polymer is generally the minimum amount of solvent. The organic phase carbonate precursor such as phosgene generally should be present in stoichiometric amounts with respect to the amount of hydroxyl functionality present in both the monohydroxy polyether and the dihydric phenol.
The aqueous phase is normally basic to the extent of a pH of at leas about 8 and preferably at least about 9 prior to reaction. During reaction, the pH may vary within the range of about 7 to 12, but preferably is kept above 7 by the addition of base such as sodium hydroxide when needed.
The dihydric carbonate forming reactants, in an interfacial polymerization reaction, are provided in the aqueous phase and when neutralized with the base are referred to the organic phase as bisphenolates. These reactants are normally formed by dissolving the bisphenols in water with an inorganic base, such as an alkali or alkaline earth hydroxide, preferably an alkaline metal hydroxide, and most preferably, sodium hydroxide. The concentrations of the bisphenolates in the aqueous phase are not critical except that the aqueous phase bisphenolate should be present in an amount sufficient to form the triblock copolymers of the present invention. The aqueous phase bisphenolates generally should be present in stoicheometric amounts with respect to the phosgenated polyether and the added carbonate precursor such as phosgene. Other materials which do not adversely affect the polymerization reaction may be present in the aqueous phase in addition to the bisphenolates and excess base, such as antioxidants, foam depressants and catalysts.
A suitable acid acceptor may be either an organic or an inorganic acid acceptor. A suitable organic acid acceptor is a tertiary amine and includes such materials as pyridine, triethyl amine, dimethyl aniline, tributyl amine and the like. The inorganic acid acceptor may be a hydroxy, a carbonate, a bicarbonate or a phosphate of an alkali or alkali earth metal, such as sodium hydroxide. A currently preferred acid acceptor is sodium hydroxide.
The carbonate catalysts which are employed herein can be any of the suitable catalysts that aid the polymerization of dihydroxy compounds with carbonate precursors such as phosgene. Suitable catalysts include tertiary amines such as, for example, triethyl amine, tripropyl amine, N,N-methyl aniline, quaternary ammonium compounds such as tetraethylammonium bromide, cetyl triethylammonium bromide, tetra-n-heptaammonium iodide, tetra-n-propylammonium bromide, tetramethylammonium chloride, tetramethylammonium hydroxide, tetra-n-butylammonium iodide, benzyl trimethylammonium chloride and quaternary phosphonium compounds such as n-butyl triphenyl phosphonium bromide and methyl triphenyl phosphonium bromide.
It is, of course, possible to employ two or more different dihydric phenols or a copolymer of a dihydric phenol with a glycol or with hydroxy or acid terminated polyester, or with a dibasic acid to provide a carbonate copolymer or interpolymer as the B segment of the triblock copolymers of this invention. Also employed in the practice of this invention may be blends of any of the above materials to provide the carbonate polymer segment.
The process for making the polycarbonates, whether by solution polymerization or by interfacial polymerization, may be carried out at ambient temperatures, such as typical room temperature condition, i.e., 23° to 25° C. Higher and lower temperatures may be employed, taking into consideration the problems of stabilizing an interfacial polymerization at temperatures above or below ambient temperatures. The solution process allows the use of a wide temperature range, no particular temperature being absolutely critical to the practice of the process of the invention. Pressure is not critical so superatmospheric or subatmospheric pressures can be used as well as atmospheric pressure. Reaction time can vary from minutes to as long as several hours.
The example which follows is intended solely to illustrate this invention and is not intended in any way to limit the scope and intent of this invention.
EXAMPLE 1
Preparation of Polyethylene-Polycarbonate-Polyethylene ABA Triblock Copolymer
Seventy grams of a monohydroxyl terminated polyethylene having an average degree of polymerization of (Henkle Corporation Primarol , 1915) was dissolved in 750 cc of methylene chloride. Twenty-five grams of phosgene was added followed by 2 cc of triethylamine. This solution was added at a rate 20 cc per minute to a 4 liter resin kettle containing 275 grams of bisphenol A, 1500 cc of water, 1500 cc of methlyene chloride and 50 grams sodium hydroxide. During the addition of the polyethylene solution, phosgene was added at a rate of 3 grams per minute. Fifty percent aqueous sodium hydroxide solution was added as required to control the pH of the polymerization mixture at 11. After the polyethylene solution and 125 grams of phosgene had been added, the pH of the mixture was decreased to 8 by the addition of more phosgene. The brine layer was separated and the polymer solution was added to two times its volume of acetone. The polymer which precipitated was removed by filtration. Analysis of the polymer by size exclusion chromatography showed it to have a weight average molecular weight of 15670 and a number average molecular weight of 6779. DSC analysis showed the polymer to have a lower glass transition temperature than an unmodified polycarbonate resin of the same molecular weight.
It is understood that the above is merely a preferred embodiment and that various changes and alterations can be made without departing from the spirit and broader aspects of the invention.
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New polymeric compositions comprising polyolefin-polycarbonate-polyolefin triblock copolymers and a method of preparation comprising reacting a monohydroxy polyolefin in an organic solvent with a carbonate precursor such as phosgene, adding the resultant mixture to bisphenol A, water, an organic solvent and an acid acceptor such as sodium hydroxide, controlling the pH of the polymerizing mixture at 11 and, after the polymerization is complete, decreasing the pH to 8 and recovering the product.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the retracting of flats from the flat bars of carding machines and specifically to an apparatus for retracting the flats from the flat bars of a carding machine.
2. Description of the Prior Art
Old, worn or damaged flats of carding machines have customarily been manually removed or retracted, respectively, from their respective cast iron flat bars. To this end use has been made of pliers, custom made or special, respectively, tools by means of which the metal clamps holding the flats and their respective bars have been detached and the flats pushed or pulled, respectively, off their respective flat bars. Such procedure involves however the risk of accidents and is time and energy consuming. Further, it has been attempted to retract the flats by aid of special tools including hooks and wedges. In addition to above mentioned risks of accident and excessive time consumption latter attempt has led often-times to damaging, breaking and destructing of the cast iron flat bars.
SUMMARY OF THE INVENTION
Hence, it is a general object of the present invention to provide an apparatus for retracting flats from flat bars of a carding machine which does not give rise to accidents and breakage of the flat bars and which allows the flats to be retracted within a significally shorter time.
A further object is to provide an apparatus comprising a supporting means for flat bars and a flat retracting wedge means operable longitudinally of said supporting means for an automatic severing of said flats from said flat bars.
Another object is the provision of an apparatus comprising a flat retracting wedge by means of which the flat and its metal clamps can be removed automatically and cleanly from the flat bar in one operating step, without damaging the flat bar. According to a preferred embodiment the retracting wedge is alternatively operable in opposite directions of the flat bar and is provided with knife edges whereby a knife edge each faces in either of said directions.
Preferably the retracting wedge is mounted to a spindle nut which is arranged on a motor driven screw spindle and is guided axially displaceable and non-rotatable thereon. However, any other suitable kind of translatory drive for such retracting wedge can be utilized, such as e.g. a driven feed chain arrangement into which the retracting wedge is coupled.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be more fully understood by reference to the following detailed description thereof, when read in conjunction with the attached drawings, wherein:
FIG. 1 is a side view of an embodiment of the apparatus for retracting flats constructed according to the present invention;
FIG. 2 is a view of a section of the apparatus shown in FIG. 1 along line II--II thereof;
FIG. 3 is a diagrammatic section through a spindle nut and a ball spindle in accordance with a first embodiment of the present invention;
FIG. 4 is a diagrammatic section through a spindle nut and a spindle in form of a worm gear in accordance with a second embodiment of the present invention;
FIG. 5 is a simplified side view, similar to FIG. 1, of a further embodiment of the present invention;
FIG. 6 is a side view of a flat retracting wedge according to an embodiment of the present invention; and
FIG. 7 is a top view of the flat retracting wedge shown in FIG. 6.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Describing now the drawings, and considering initially the exemplary embodiment shown in FIGS. 1 and 2, it will be understood that the same comprises a base plate 59 which supports a base frame 7 made of L-shaped profile irons. The base frame 7 is covered by a steel plate 20 which is welded thereto. This steel plate 20 carries at both its ends an upright supporting column 6. These columns 6 support a horizontal hollow beam 8 with a rectangular square section. This hollow beam 8 carries in turn on both its sides an upright standing guide plate 12, the beam 8 and plates 12 defining a guideway. The supporting columns 6 support, furthermore, a screw spindle 3 which is driven by a motor 4 by means of a toothed belt 5 engaging on one side a sprocket 21 mounted to the driving shaft 23 of motor 4 and engaging on the other side a sprocket 22 coupled rigidly to screw spindle 3. The screw spindle 3 engages threadingly a spindle nut 2. This spindle nut 2 is rigidly connected to a carriage 14. (See FIG. 2.) Carriage 14 is provided with rollers 24 which are supported and guided in the guide plates 12. Accordingly, carriage 14 is movable longitudinally of and supported by the hollow beam 8 and guided therealong by the guide plates 12.
Mentioned spindle nut 2 carries a retracting wedge 1 which will be described more in detail further below. The beam 8 carries, furthermore, two limit switches 13,13' limiting the extent of travel of the spindle nut 2 along the spindle 3. The limit switches 13,13' are operated by a plate 25 defined by one leg of an angle piece 26 secured to the spindle nut 2. Due to the guidance provided by the beam 8 with a square cross-section and by the guide plates 12 a lateral displacement of the retracting wedge 1 is positively prevented.
In the embodiment shown in FIG. 1, of which a detail is shown in FIG. 4, the screw spindle 3 is a threaded spindle meshing with the accordingly designed spindle nut 2 having an inner thread 27.
According to a further embodiment, see FIG. 3, the spindle nut 2 is provided with bearing balls 28 arranged in an endless channel 29 formed therein, whereby the screw spindle 3 is provided with a recess 30 extending in a screwlike fashion therealong. This arrangement reduces the friction forces between spindle nut 2 and spindle 3.
In accordance with a further embodiment a feed chain arrangement for the carriage 14 is provided in place of the spindle nut 2 and spindle 3, such as shown in FIG. 5. Thereby, carriage 14 is mounted to an endless chain 31 supported and guided at one end by an idler sprocket 32 and at the other end by a driving sprocket 33, (corresponding operationally to sprocket 22 of FIG. 1), which in turn is driven from motor 4 by conventional means.
Attention is now drawn again to FIG. 1. The base frame 7 supports two supporting pedestals 17, 18 for the flat bar 10. In order to allow the handling of flat bars 10 of various design the supporting height of the two pedestals 17, 18 is adjustable. To this end the pedestals 17,18 are provided with elevating screws 17',18'. These elevating screws 17',18' can be operated by knurled nuts 34,35. By rotating the knurled nuts 34,35 the supporting height of the pedestals 17,18 can be altered individually.
Furthermore, the supporting pedestal 18 shown at the right side of base frame 7 is adjustable in a direction parallel to the threaded spindle 3, such to accommodate flat bars of various lengths. Accordingly, the base frame 7 is provided with two grooves extending parallel to the spindle 3 and supporting pedestal 18 comprises corresponding mounting elements. This construction is well known in the art and thus not particularly shown. In FIG. 1 there is shown however a locking lever arm 36 with which pedestal 18 is to be locked or unlocked, respectively, in mentioned grooves.
The two supporting pedestals 17,18 are intended solely for supporting a flat bar 10. Such flat bar 10 is held or locked, respectively, in place by means of two pneumatically operated clamping devices 15, such as shown in FIG. 1 and 2.
These clamping devices comprise a fixed clamping member 37 rigidly connected to the base frame 7. A movable clamping member 38 is pivotally mounted to the fixed clamping member 37 by the agency of a pivot pin 39. The upper flat engaging end of the fixed clamping member 37 carries a flat engaging bar 40 and corresponding movable clamping member 38 carries a corresponding flat engaging bar 41, the bars 40,41 being constructed from a relatively soft material to avoid damaging of the flat bar clamped therebetween.
The lower end of the movable clamping member 38 is hingedly connected to the piston rod 42 of a compressed air cylinder 16. The compressed air cylinder 16 of either clamping device 15 communicates by means of an air hose 43 (see FIG. 1) with a control- or actuation valve 9, respectively, which may be operated by the hand or the foot of an operating person. The control valve 9 communicates by means of a pressurized air supply hose 44 to a source of pressurized air (not shown).
An embodiment of the retracting wedge 1 is shown in FIGS. 6 and 7. This wedge is a massive body having two through holes 45,46 with a recess 47,48 for receiving a hollow screw with head by the agency of which the wedge 1 is mounted to the bottom side of carriage 14.
The wedge 1 features seen in plan view a hexagonal shape including a front knife or separating edge 1a and a rear knife or separating edge 1b. As shown, each knife edge 1a, 1b is provided with two knife edge sections 49,50 extending at an angle relative to each other thus forming together a tip 51. According to FIG. 6 and 7 the knife edges 1a, 1b are defined by the bottom surface of wedge 1 and first slanted wedge surfaces 53,54. These first wedge surfaces 53,54 are followed by stronger sloping guide surfaces 55,56 for guiding the severed flat 11 (FIG. 1) upon its detachment from the flat bar 10 as will be explained further below. Thus, the wedge 1 is not only intended for severing the flat 11 from the flat bar 10 but also for guiding the detached parts to avoid any entanglements.
The operation of the flat retracting apparatus is as follows. Firstly, the supporting height for the respective flats to be handled is adjusted by means of operating the knurled nuts 34 of the flat supporting pedestals 17,18. Thereafter the distance between the flat supporting pedestals 17,18 is adjusted in accordance with the length of the flats to be handled in that locking lever arm 36 of pedestal 18 is operated and pedestal 18 adjusted longitudinally of the flat retracting apparatus. Thereafter pedestal 18 is locked in place by operating locking lever arm 36.
It shall be assumed that the retracting wedge 1 is in its right side end position, i.e. adjacent the limit switch 13' mounted below motor 4.
By depressing the operating lever 57 of the control valve 9 the compressed air cylinders 16 are put in operation such that the movable clamping member 38 pivots around pivot pin 39. Accordingly, the clamping bar 41 of the movable clamping member 38 moves away from the clamping bar 40 of the fixed clamping member 37. The flat bar 10, from which the flat 11 is to be removed, can now be inserted therebetween and upon release of the operating lever 57 of the control valve 9 the flat bar 10 is firmly gripped by and held in the clamping devices 15. Thereafter the "ON" button 58 of the control panel 19 is pushed. (61 designates the "OFF" button and 60 designates the emergency stop button.) Accordingly, motor 4 is set in motion and begins to drive spindle 3 (or chain 31 of the embodiment of FIG. 5). Wedge 1 begins to move to the left.
Because the position, i.e. the height of the upper surface of the flat bar 10 has been exactly adjusted by the supporting pedestals 17,18 the vertical clearance between the bottom surface 52 of the retracting wedge 1 and the upper surface of the flat bar 10 is extremely small such that the leading tip 51 of the wedge 1 will penetrate between the upper surface of the flat bar 10 and the flat 11 proper and a lifting off of the center area of the flat 11 will be initiated. Immediately thereafter the leading knife edge sections 49,50 penetrating obviously also between the flat bar 10 and the flat 11 engage the two metal clamping webs 62 with which the flat 11 is clamped to the clamp bar 10 and pry the two clamping webs 62 laterally away from the flat bar 10 and flat 11.
The flexible flat 11 thus severed from the flat bar 10 is guided by the leading first wedge surfaces 53,54 and thereafter by the leading guide surfaces 55,56 of the retracting wedge 1 such that it is looped back on itself in a manner shown in FIG. 1.
The retracting wedge 1 keeps on moving to the left until the flat 11 and the clamp 62 are completely severed from the flat bar 10 whereby no manual work must be performed and until it strikes the limit switch 13 thus stopping motor 4.
Whilst the retracting wedge 1 remains in its left side end position the flat bar 10 freed of its flat 11 is removed from the apparatus by pneumatically operating the clamping devices 15 and a new flat bar 10 is inserted into the supports 17,18.
Upon pressing the "ON" button 58 the retracting wedge 1 moves from the left to the right and performs the severing of the new flat 11 from the new flat bar 10 in the opposite direction.
Because no manual labour must be performed for the severing of the flats 11 and because the wedge 1 operates in both directions a time and cost saving as well as safe operation of retracting the flats from the flat bars can be performed.
Since many modifications, variations and changes in detail may be made to the described embodiments, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense and may be otherwise variously embodied and practised within the scope of the following claims.
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An apparatus for the retraction of worn flats from the cast iron flat bars of a carding machine. A retracting wedge is mounted on a spindle nut which is threadingly mounted on a threaded spindle and movable longitudinally thereof. The apparatus is provided further with supports and clamping devices for a flat bar, which supports and clamping device are arranged such that the flat bar mounted thereon extends parallel to mentioned spindle. Upon rotating the spindle the retracting wedge moves longitudinally along the flat bar whereby its knife edges separate the worn flat from the flat bar. The retracting wedge is operable in both longitudinal directions of the threaded spindle.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of copending application Ser. No. 907,667 filed May 19, 1978 for Heat Extractor now U.S. Pat. No. 4,340,572.
BACKGROUND OF THE INVENTION
Certain features of said previous application shown and described, but not claimed therein, are shown and described and claimed in the present application, and other features of the previous application shown, described and claimed therein are shown and described, but not claimed, in the present application. Other features are shown, described and claimed for the first time herein.
1. Field of the Invention
The present invention pertains to the efficient utilization of fuel. Even more specifically, the invention relates to the efficient utilization of fuel such as oil fuel or gas fuel burning in a furnace, usually a domestic furnace, although not necessarily so. The present invention differs from that of the initially filed application which related to the burning of fuel, including coal, wherein the flue gas stream included particulate material. Pursuant to the present invention, there is little or no particulate material in the flue gas, and the particulate material that is present principally takes the form of soot. Even this only is present when oil is burning and is almost entirely absent when gas is burning. A gas flame is very clean and creates essentially no particulate loading. An oil flame may, and frequently does, have some toxic material in its products of combustion and, as a rule, a gas flame has no toxic fumes in its products of combustion. The combusted gas stream issuing from a furnace that is burning gas does not require cleaning, and the combusted gas stream that is fed to a smokestack from a burner that is operating with a properly balanced oil burner does not, as a rule, require very much cleaning. The special field of the instant invention is particularly concerned with the recovery of heat from the stack gas of domestic furnaces and, in the process, reducing the temperature of the stack gas to, or close to, ambient temperature.
More particularly, the present invention pertains to a heat recovery system in which stack gases from an oil- or gas-fired domestic furnace are diverted in their passage to a chimney and routed through a heat recovery unit where the heat from the waste gases is recovered and used, for example, to heat tap water which subsequently can be employed for domestic hot water or as a hot air preheater. The present invention has several other features too numerous to describe at this point but which will be pointed out as the description proceeds.
2. Description of the Prior Art
The recovery of low level, previously wasted heat from sources such as flue gas has received attention in recent years because of the energy crisis. The cost of conventional fuels such as oil, coal, and especially natural gas, has escalated to the point where it is now profitable to install ancillary heat recovery units to recover previously wasted heat contained in system effluents such as flue gas. The problem of efficiently and usably recovering such heat is compounded by the fact that it is available only at a relatively low temperature level and, in the case of flue gas, the sensible and latent heat contained in the gas must be recovered from a large quantity of gas having a low heat content. Flue gas produced by burning sulfur-containing fuels is of an extremely corrosive nature, especially when the flue gas is scrubbed by aqueous media which generates sulfurous and sulfuric acids in situ.
Heat recovery schemes of various types are shown in U.S. Pat. Nos. 1,986,529; 2,878,099; 3,169,575; 3,439,724; 1,083,885 and 4,129,179.
SUMMARY OF THE INVENTION
1. Purposes of the Invention
It is an object of the present invention to provide a method and apparatus for the efficient and economical recovery of heat.
It is another object of the present invention to recover heat from low temperature sources in an improved manner.
It is a further object of the invention to increase the thermal efficiency of domestic heating apparatus to 95%.
It is another object of the invention to recover heat from fossil fuel combustion waste gas streams economically and providing 95% or greater utilization of the heating value without the deterioration of the heat transfer system by the products of combustion.
It is a further object of the invention to efficiently recover waste heat in a domestic furnace.
It is a further object of the invention to provide a high heat transfer and low mass transfer device and method for the direct contact transfer of heat from a gas to a liquid medium.
It is a still further object of the invention to recover usable heat from a waste gas stream.
It is yet another object of the invention to recover previously wasted heat from process gas streams.
It is another object of the invention to lower fuel consumption in facilities which generate a hot waste gas stream.
It is a further object of the invention to aid in alleviating the energy crisis facing the nation.
It is still another object of the invention to raise the overall thermal efficiency of installations which generate low level heat, that is to say, low to moderate temperature gas streams.
It is yet another object of the invention to provide a method and apparatus for recovering usable heat from a waste gas stream which can be of original equipment manufacture or retrofitted to any existing heating installation.
It is a further object of the invention to recover heat previously lost by atmospheric discharge of flue gas through a chimney stack.
It is still another object of the invention to heat process water, preheat boiler water makeup, heat spaces and provide moderate temperature heat for other applications using previously wasted heat which is recovered in an efficient and economical manner.
It is a further object of the invention to economically and thermally match heat transfer systems to provide comfort heating by the combustion of fossil fuels and their most efficient utilization.
It is a further object of the invention to economically and thermally match heat transfer systems to recover heat from waste gas streams from fossil fuel combustion to provide comfort heating or other domestic use.
It is another object of the invention to provide a method and apparatus which will create an automatic draft effect for flue gas to be fed from a smokestack through a contact unit.
It is another object of the invention to provide a method and apparatus which will automatically provide a lower pressure path when the same is operational with gases which are transferring heat to a process fluid and yet which, when this alternate is not functioning, will automatically fail-safe to a chimney path.
It is another object of the invention to provide a method and apparatus in which a pump is employed to force heated water through a heat exchange unit while the water is being heated by heat from the flue gas, the pump being turned on by a burner control, but turned off by a fan control so that the pump is deactivated only at the last moment and pumps until the water moved thereby is almost cold.
These and other objects and advantages of the present invention will become evident from the description which follows.
2. Brief Description of the Invention
In the present invention, the method of recovering usable heat from a gas stream includes providing an external sump in which water is accumulated. The water is pumped from the sump to a heat exchanger located in an entrance box connecting returning air from the heated space to the furnace or other heating mechanism so that if the water is warm it will preliminarily heat this return air.
Water is pumped from the heat exchanger to a water jet in a hood above the sump. This jet constitutes a spray providing good water contact between water droplets and the hot exhaust gases so that the hot exhaust gases cool down and the water is heated and falls warm into the sump. The spray also exerts an accelerating force on the exhaust gases, creating a draft or suction which induces the flow of gases through the diversion smoke pipe leading from the chimney to the space above the sump.
A second jet in the diversion smoke pipe is fed by the pump to provide the induced draft whereby to move the hot exhaust gases and to heat the water which has its temperature raised considerably.
The water is pumped back out of the sump to the heat exchanger and to the jets, continuing in a recirculating path and further raising the temperature of the heat exchanger and therefore of the heated return air. This continues as long as the pump is running. Ultimately, the pump stops, being turned off when the fan on the furnace blower is turned off; that is to say, a common control turns them both off. By the time that the fan turns off, the hot water in the sump has cooled considerably so that most of the heat in the sump has been dissipated by heating the return air and maximum use has been made of this hot water, thereby increasing efficiency of the system.
The system has certain advantages; thus, the system fails-safe. For example, the two Venturi effects provided by the jets successively reduce the pressure in the diversion smoke pipe. If either of these fail, the low pressure in the diversion smoke pipe, which during normal operation of the system is below chimney pressure, rises to a pressure above the pressure in the chimney so that the flow of the exhaust gases now takes place through the old chimney instead of through the flue gas exit. It is pointed out that, due to the heat extracted by the sump, the flue gases leave through the flue gas exit at a temperature of about 90° to 100° F. in contrast to a temperature of about 400° to 700° F. at which it would normally exit through the old chimney, and thus, the temperature to which it will return if there is a blockage preventing exit from the flue gas exit.
BRIEF DESCRIPTION OF THE DRAWING
The sole FIGURE is a perspective view of an apparatus for carrying out the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now in detail to the sole FIGURE, the reference numeral 10 denotes a system incorporating the invention. Said system has either been retrofitted or built to include original equipment so that it can function pursuant to the present invention. Regardless of whether it is retrofitted or is equipment of an O.E.M., the system 10 includes certain basics plus certain auxiliaries pursuant to the instant invention. The basics include a furnace 12 connected to a chimney (not shown). It should be mentioned that the chimney is part of the original equipment. Even if the furnace is being installed new, a chimney will be built to go along with it. It is "part of the package". The chimney exits at a high point in the building as is conventional and, also as is conventional, usually will be made of brick or is lined with clay tile inside a brick flue, and will draw a substantial draft. The draft is far too much for the furnace needs, in view of the fact that the furnace is essentially fuel efficient and operates on a low air-to-fuel ratio.
A flue pipe 16 connects the combustion chamber 18 of the furnace to the chimney through one branch of a T-fitting 20. A standard fuel burner (not shown) is located in the combustion chamber. This either will be a gas burner or an oil burner, depending on the fuel to be burned, and will be tuned for maximum burner efficiency.
Air is supplied from the room in which the furnace is located, e.g. a cellar. In order to reduce the amount of draft at the furnace, it is customary to provide the casing of the furnace with a shuttered opening, that is to say, an opening having a damper 24 therein known as a diverter.
Internally the furnace includes a furnace heat exchanger 26.
Assuming that the furnace is a hot air furnace, return air is fed from the various rooms through sundry collector ducts (not shown) to a return duct 28 that leads to a collector box 30 from which the air is introduced into the furnace heat exchanger. A preheater heat exchanger 32 is located in the collector box for the purpose of warming air passing through said box on its way to the furnace intake via the furnace blower 22.
The furnace blower is controlled by an electrical system (not shown) which is controlled thermostatically by air temperature as, for example, in one of the ducts. A conventional thermostat (not shown) is employed to start the furnace. When the temperature of the thermostat drops below a predetermined setting, the furnace burner turns on. When it rises above a certain setting, the furnace burner shuts off.
For recovery of heat from the combusted exhaust gases, the combusted gases are diverted from the chimney. For this purpose, there is provided a diversion smoke pipe 34 connected to a second branch of the T-fitting 20 and running to an elbow 36. Preferably, the elbow is connected to the diversion smoke pipe so that it is readily replaceable because this elbow may be subjected to highly corrosive materials. The metal is essentially impervious. However, the liquid is corrosive and in time there may be need for replacement.
Preferably, the elbow 36 is made of stainless steel because it is constantly being sprayed with water from a jet 44 located in the center of the bend of the elbow on the outer side thereof and is fed with acidic water under pressure from a pump 46. The jet is directed toward the run 38. The jet is an expanding conical jet in the form of a cone of fine beads of water the configuration of which is indicated by dotted lines in the sole FIGURE of the drawing. The jet strikes the hot flue gases passing through the diversion smoke pipe leading from the out-of-use chimney, these gases being absorbed and dissolved in the water and some of the gases forming sulfurous and sulfuric acids which are corrosive. It is because these acids are corrosive that the pipe preferably is made of a material highly resistant to such corrosion, and it is for the same reason that the elbow and pipe may need to be replaced.
It also should be mentioned that the water jet has a Venturi effect. It introduces a draft in the elbow and run of pipe as well as in the diversion smoke pipe which reduces gas pressure in the diversion smoke pipe and pulls exhaust gases from the old chimney route into the diversion smoke pipe.
To assist this diversion action, a second water jet is provided, this latter jet being located in the hood 40. The second jet is denoted by the reference numeral 48 and it, too, is indicated by dotted lines in the drawing. It, too, creates a fine conical spreading spray but it is confined to the hood and is directed downwardly into the bottom of the hood and into the broad base of the contact section 42.
The contact section will be seen to be comprised of three essential parts, namely, the hood 40, a sump 50 covered by a lid 52, and a vent 54 extending from the lid 52 to an exit point at the side of the house considerably below the chimney exit.
The second jet 48, as noted above, further pulls exhaust gases along the diversion smoke pipe. It also further reduces the temperature of the exhaust gases until, finally, the exhaust gases, by the time they reach the exit from the vent 54, are at a temperature of about 90° to 100° F. In other words, they are quite cool as they exhaust from the vent out the side of the house.
The water for the two jets 36 and 48 is supplied by the pump 46. The outlet from the pump passes through a conduit 56 through a T 58 to another conduit 60 which leads to the jet 36. From the T a branch conduit 62 leads to an inlet for the preheater heat exchanger 32 the outlet from which passes through a conduit 64 that leads to the jet 48.
Cold water is supplied to the sump 50 through a supply pipe 66 entering the sump through a conventional float control valve (not shown) located inside the sump. This valve controls the level of water in the sump. When the level reaches a predetermined setting, it is cut off by closing of the valve through raising of the float. If there is too much water present, it runs out through an overflow 68 leading to a drain.
There are several interesting features to the system just described. For one thing, it is a fail-safe. Thus, if one or both of the jets fail, for instance by failure of the pump, the pressure within the diversion smoke pipe automatically rises to above the pressure prevailing in the old chimney which has been left in the system and which then starts to function so that it replaces the vent 54. Such replacement takes place automatically because the pressure in the diversion smoke pipe then exceeds the pressure in the chimney. The difference between the two pressures, when the diversion smoke pipe is functioning, is caused by the operation of two Venturi effects brought about by the jets 36, 48.
Another interesting effect of the present furnace is that, because it operates so efficiently, it draws in very little air from its surroundings and, hence, wastes but little heat. Unlike many hot air furnace installations, it does not suck in appreciable amounts of warm room air and allow it to escape up the chimney, i.e. its intake of room air is negligible because of the low chimney temperature so that there is essentially no fuel lost in heating up such air. That would represent an inefficient operation.
A further interesting observation to be noted is the omission of a vent damper which is conventionally found in many oil- or gas-fired furnaces. The present furnace has no vent damper. The damper can be eliminated because the instant furnace does not employ a hot stack, i.e., a chimney, so there is no need to relieve a substantial draft created by it.
It thus will be seen that there is provided a device which achieves the various objects of the invention and which is well adapted to meet the conditions of practical use.
As various possible embodiments might be made of the above invention, and as various changes might be made in the embodiment above set forth, it is to be understood that all matter herein described or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.
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A heat extractor system for a furnace, said furnace including a burner with a chimney that is connected but is normally not in operation. Instead, the furnace is connected to a vent in parallel with the chimney through a draft-inducing arrangement including a water spray in which water is heated and circulated to a point where the heat from the water is utilized. Due to the parallel arrangement of the vent and chimney, if the vent fails to operate, it will function in a fail-safe manner, with the combusted gases from the burner leaving through the chimney.
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TECHNICAL FIELD
This invention relates to a method and a device for detecting the presence of enzyme inhibitors in a fluid medium such as air or water. An aspect of this invention related to the detection of nerve agents (such as Tabun, Sarin, Soman, VX, etc.), various other toxic agents (such as cyanide), environmental pollutants, and other substances capable of inhibiting the enzymatic activity of enzymes such as the cholinesterases, hexokinase, and the like. Still another aspect of this invention relates to the collection and specific identification of such substances in the atmosphere or other areas of the environment such as water supplies. A still further aspect of the invention relates to instrumentation for implementing the aforementioned methods including point source alarms, dosage monitors, and detection/identification systems.
DESCRIPTION OF THE PRIOR ART
It is well known that enzymes such as the cholinesterases are useful in methods and devices for detecting the presence of nerve agents, pesticides, and other toxic substances. The cholinesterases and similar enzymes are inhibited by these substances; hence tests for enzyme activity (or the lack of enzyme activity) can reveal the presence of the toxic substance. For example, a layer of a cholinesterase can be exposed to a sample of surface water (from a lake, stream, or other body of water), or an aqueous solution through which air has been bubbled, and the activity of the thus-exposed cholinesterase can be measured chemically, biochemically, or with an electrical or electronic instrument. A lack of activity indicates that the cholinesterase has been inhibited by a substance in the sample of air or water to which the enzyme layer was exposed.
Typically, the concentration of toxic substances or agents in the air or water supplies is small, but even very small concentrations can be brought within the range of sensitivity of prior art methods. One known means for insuring high sensitivity involves collecting trace quantities of the agent upon or in a sensitive collection medium thereby increasing the concentration of agent for detection or monitoring purposes. Various adsorbents (e.g., "TENAX," "PORAPAK Q," and activated charcoal) collect agents satisfactorily when sampling clean air. However, when these adsorbents are used in an outdoor environment, they collect other airborne substances which may mask the presence of specific agents.
To improve both sensitivity and specificity of detection, immobilized cholinesterase has been used to collect as well as detect agents such as dimethyl-2, 2-dichlorovinyl phosphate (DDVP) at concentrations as low as 0.4 mg/m 3 when the sampled air volume is 2 liters. See A. W. Barendsz, Intern. J. Environ. Anal. Chem. 6:89 (1979), wherein there is disclosed a detection tube containing an indicator layer and butyrylcholinesterase immobilized in a gelatine preparation. The sealed glass ends of the detection tube can be broken off and a volume of air (e.g., 2000 cm 3 ) pumped through the tube. Observation of a strong blue color change indicates no change in enzyme activity, i.e., that no agent was collected--or that the amount of agent collected was below the lowest level of sensitivity of the test method. But if the air sample has inhibited the butyrylcholinesterase due to collection of enzyme inhibitors in the gelatine preparation, the deep blue hydrolysis product will not be observed in the indicator layer.
The foregoing prior art method is believed to be specific for cholinesterase inhibitors (anticholinesterases) and some very closely related compounds--a fairly narrow class of agents. However, it is believed to be difficult to ascertain by this method which of the anticholinesterases has been detected. That is, it is particularly desirable to have a relatively simple method and device which is specific as to the class or classes agents which it collects and concentrates and which is capable of being specific in its detection or monitoring responses, even within the bounds of the class which has been collected. Such a method or device would have two levels of selectivity: it would screen out all compounds except certain enzyme inhibitors or substrates in the collection stage, and it would provide further specificity in the detection or monitoring stage, thereby identifying the agent which has been collected.
SUMMARY OF THE INVENTION
It has now been found that analytical techniques based upon the emission and subsequent measurement or detection of wave energy (e.g., infrared radiation) can be used to detect the presence of enzyme inhibitors such as the anticholinesterases, and, if desired, to identify the specific inhibitor which has been detected. The adaptation of these analytical techniques to the field of detecting and/or monitoring and/or identifying the inhibitor is based in part upon the discovery that one or more readily detected or measured characteristics (e.g., the infrared absorption) of the enzyme (e.g., a cholinesterase, hexokinase, or other enzyme sensitive to toxic agents or the like) are significantly altered after the enzyme has been used to collect the agent to be detected.
Although this invention is not bound by any theory, it is believed that the agents of concern in the context of this invention form a third substance (which can be referred to as EnzInhib), distinct from both the enzyme and the agent, which has its own identifiable characteristics, e.g., a distinctive infrared adsorption spectrum whether the enzyme is in solution or in a dry state when exposed to the inhibitor. It is by no means universally accepted in the art of analytical chemistry that alterations in the structure of both the enzyme and the inhibitor occur when dry enzyme and inhibitor come together or that the two form a complex with a new chemical bond. Studies done in connection with this invention suggest that such structural alterations probably do occur, however. Additional data, although not as extensive, suggest that the complex is inhibited enzyme. Prior art workers have studied the infrared spectra of various uninhibited enzymes and various substrates or inhibitors, but spectral data on solubilized enzyme-inhibitor combinations appear to be relatively scarce. Spectra of dry enzymes, without or without inhibitor, have apparently not been reported. It has now been found that, using the uncomplexed or uninhibited enzyme spectrum as basis for comparison, dramatic spectral changes can occur after collection of the inhibitor with the enzyme, particularly when the inhibitor is a chemical warfare agent or an organophosphorous pesticide. This phenomenon can be qualitatively detected and--to some extent--quantitatively measured with known infrared spectroscopic techniques. When comparing absorption spectra ("inhibited" vs. "uninhibited" enzyme), it has beed found that absorption peaks can be shifted, reduced in intensity, or even substantially eliminated. Furthermore, new absorption peaks may appear in the "inhibited" spectrum which were not present in the "uninhibited" spectrum.
Again, this invention is not bound by any theory, but the foregoing spectra comparisons are believed to support the concept that the inhibitor (e.g., a nerve agent) gets tied into the enzyme structure in some manner, resulting in losses or changes in chemical substituents or functionality of the inhibitor and/or the enzyme. Theoretically, then, the complex EnzInhib is a unique chemical species, differing identifiably from both of its parent compounds or precursors. Even if this theory is not correct, the aforementioned changes in the spectra are sufficiently dramatic to insure the practicality of this invention. Not only do these spectral changes reveal that an inhibitor has been collected by the enzyme, they also tend to identify the specific inhibitor, since different inhibitors appear to cause different spectral shifts with respect to the same enzyme. Mixtures of inhibitors can, if desired, be sorted out and separately identified.
Briefly, then, the method of this invention, which enables one to detect the presence of one or more given enzyme inhibitors in a fluid medium, comprises the steps of:
(a) collecting a portion of the inhibitor in the fluid medium by bringing the fluid medium into contact with substantially uncomplexed or uninhibited enzyme (the uncomplexed enzyme being preferably in a dry, immobilized state), thereby forming an enzyme-inhibitor combination, and
(b) detecting any wave-energy interaction characteristic of the enzyme-inhibitor combination at a given wavelength which is different from the wave-energy interaction characteristic of the substantially uncomplexed or uninhibited enzyme at that same wavelength.
Preferably, the wave energy is infrared energy, and the most conveniently detected interaction with this energy is absorption or transmission, which can be measured with conventional infrared spectrometers or with multiple internal reflection (MIR) infrared spectroscopy. The fluid medium can be air, water, solvents, carrier gases, etc. and the results obtained with the method can be annunciated with an alarm sound or light, a digital readout, a print-out, a continuous plot on graph paper, an analog signal on an electronic display, or other electrical or electronic or acoustic or hard-copy forms of display or annunciation. Controlled studies can generate the baseline data for comparing the infrared absorption characteristics of the enzyme-inhibitor combination with the substantially free or uninhibited or uncomplexed enzyme and also suggest specific wavelengths or frequencies which will provide a particularly definitive determination of the presence of a given inhibitor or agent.
Devices useful in this invention can either be fully integrated (with collection or sampling means and sample identification or detection equipment all combined in one unit) or can consist essentially of sample identification equipment constructed and arranged to receive a sample collected with a separate unit such as an exposure badge or water-sampling kit.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic representation of an infrared identification device of this invention.
FIG. 2 is a modified form of the device of FIG. 1 with means to permit analysis of liquid samples.
DETAILED DESCRIPTION
While this invention can be used to detect the presence of pollutants (herbicides, pesticides, etc.) and a wide variety of non-military toxic substances through selection of appropriate enzyme collectors, the following description will, for the sake of brevity, focus on chemical warfare agents such as GB (Sarin), GD (Soman), VX, L, BZ, Tabun, mustard gases, and organophosphorus compounds which complex with cholinesterases. The principles of this invention are easily adapted to industrial and other non-military applications. Known enzymes can collect or complex with pollutants or toxic substances having no substantial military use.
In detecting or monitoring for the presence of nerve agents, the normally preferred class of enzymes is the cholinesterases. The toxicity of nerve agents stems from their ability to irreversibly inhibit this type of enzyme, which is necessary for the proper functioning of the nervous system. Once the agent has inhibited the enzyme, it rapidly undergoes hydrolysis, a process known as "aging," which makes reactivation of the enzyme impossible; the enzyme-agent complex is chemically the same compound after aging whether the agent (inhibitor or anticholinesterase) was GA, GB, GD, or VX. It might be expected, therefore, that identification of the inhibitor would not be possible. It has been found, however, that such identification can be possible when airborne anticholinesterases are collected with dry, immobilized cholinesterase. Apparently, the "aging" process is substantially slowed so that an identifiable moiety of the anticholinesterase maintains its unique composition or structure indefinitely when kept relatively dry. Accordingly, from the standpoint of accuracy of identification, dry cholinesterase is the preferred collecting matrix. Cholinesterase is readily immobilized by fairly simple techniques, e.g., adsorption on filter paper. Gels have also been used for immobilization. Immobilization is not absolutely essential for sampling air, however. For example, dry crystalline cholinesterase can be packed in a tube with fibrous plugs at each end, and air can be pumped through the tube.
If a high degree of specificity is desired for identification of water-borne agents, the enzyme can be entrapped or convalently bound to or absorbed on surfaces to be used to collect nerve agents in water. In the context of this invention, it has been determined that immobilization by covalent binding of cholinesterase tends to slow the "aging" process significantly, and some specificity of identification is possible even in water solution. Chymotrypsin, another enzyme which is inhibited by nerve agents, is reported to be resistant to "aging" and thus presents an alternative to cholinesterase for identification of water-borne agents.
There is a controversy in the literature as to whether vesicants such as mustard gas are cholinesterase inhibitors. In an embodiment of the enzyme collection/infrared spectra comparison technique of this invention (using crystalline acetyl cholinesterase from eels) only minor differences in the spectra were observed. Accordingly, better detection of mustard gas can be obtained with a different enzyme or enzyme preparation. On the other hand, eel, bovine, and horse serum acetyl cholinesterase were all found not only to be effective in detecting nerve agents (GB, GD, etc.) an organophosphorous agents (including "Malathion," "Fonofos," and "Dichlorvos") but also in distinguishing these various agents from each other. Devices for the detection of nerve agents and blistering agents may have mixtures of enzymes or separate ports or windows, i.e., a window for each enzyme. In the case of a detection or monitoring device exposed to both nerve agents and organophosphorous pesticides, separate enzyme collectors are ordinarily not necessary, since the characteristic shifts or new peaks or reduced intensity peaks in the cholinesterase-nerve agent spectra are somewhat different in frequency and generally non-interfering with respect to the characteristic bands of the cholinesterase pesticide spectra. This lack of interference between two closely related classes of cholinesterase inhibitors is considered a highly advantageous feature of this invention.
Presently available data also indicate that uncontrolled exposure to the atmosphere in an urban environment (which presumably contains a variety of airborne pollutants) does not interfere with nerve agent detection and identification, even if no attempt is made to flush off the nonspecifically adsorbed pollutants. In short, the present invention appears to have a capability for detecting or monitoring or identifying specific individual agents, specific classes of agents, or selected groups of individual agents or classes of agents. Given the teachings of this invention, it is within the skill of the art to select the particular enzyme or groups of enzymes to be used as collectors (e.g., one or more cholinesterases, chymotrypsin, hexokinase, an combinations of these enzymes).
Commercially available crystalline acetyl cholinesterases (AChE) perform well in detectors and monitors made according to this invention, as do the so-called pseudo-cholinesterases (BuChE) obtainable from horse serum or human serum.
Acetyl cholinesterase occurs as a membrane-bound enzyme and is obtained in commercial quantities from electric eels or bovine erythrocytes. The base line spectra (uninhibited or uncomplexed enzyme spectra) of, for example, eel, bovine, and horse serum cholinesterases differ markedly from each other, but each base line shows significant shifts or changes after collection of a nerve agent or organophosphorous pesticide. Indeed, the differences between the cholinesterases in base line spectral data can be put to good use; BuChE may be the enzyme of choice for one agent, and AChE for another.
DETECTION, MONITORING, AND IDENTIFICATION DEVICES
For convenience of description, it will be assumed that the devices discussed below are designed to detect and/or monitor and/or identify nerve agents or organophosphorous pesticides. It will also be assumed that detection (e.g., determining the presence or absence of an agent in a fluid sample), monitoring (e.g., use of real-time monitors for demilitarization plants, personnel exposure badges, etc.), and identification (determining which particular nerve agent or pesticide has been detected or monitored) will all be accomplished through collection by an enzyme (preferably a cholinesterase) and infrared analysis of the resulting enzyme-agent or enzyme-pesticide complex. Because of the relatively well-defined widths and locations of many of the infrared absorption bands of interest, the infrared analysis of the Enz-Inhib complex may be confined to a single wavelength or wave number, narrow band of wavenumbers, or a few wavelengths or bands of wavenumbers. For example, if the agent to be detected is GB, and the GB is collected and concentrated on a layer of immobilized bovine erythrocyte acetyl cholinesterase (AChE), a reasonably sharp absorption peak for the AChE-GB complex should be observed at about 13.8 micrometers, i.e. 725 reciprocal centimeters (cm -1 ), which peak is substantially nonexistent in the uninhibited bovine erythrocyte AChE spectrum.
Thus, to analyze samples for AChE-GB, where the AChE is from bovine erythrocytes, the infrared source can be optically narrowed to 700-750 cm -1 , and the determination of percent transmission of the focused 700-750 cm -1 beam can be made with respect to an attenuated reference adjusted to the equivalent of about 65% transmission. The reference will be less transmissive than an uninhibited bovine AChE sample; hence an AChE sample which has collected no GB will be "seen" as lacking an absorption band at the selected range of wavelengths. An absorption peak at approximately the same wavenumber i.e., 725 cm -1 appears to indicate the AChE-GD complex as well as AChE-GB. In cases where both agents may be expected to be present, a second wavenumber, e.g., 950 cm -1 , may also be monitored. There is strong absorption in uncomplexed enzyme and in AChE-GB at this wavelength, but a substantial decrease in absorption for the AChE-GD complex. Thus an increase in absorption at 725 cm -1 with no change at 950 cm -1 would be "seen" as AChE-GB, while an increase at 725 cm -1 and a decrease at 950 cm -1 would be "seen" as AChE-GD. Substantially similar arrangements can be made for detecting AChE-GD and AChE-GB when the acetyl cholinesterase is obtained from electric eel sources.
In the case of Malathion, the BuChE-Malathion spectrum has a characteristic absorption peak at about 1000 cm -1 (about 10 micrometers) which does not appear in the uninhibited BuChE spectrum. Thus, Malathion can be detected, monitored, and identified in a manner analogous to the nerve agents.
In any case, the output of the spectrophotometric cell can be converted to either a digital or analog signal which can be compared in numerical value or in intensity to a reference signal. The differential output from the comparison means can be fed to a digital display, alarm means, print-out device, or the like. The area of a peak can be integrated by computer and compared to the area of reference peaks by known techniques.
As noted previously, immobilized "dry" enzymes are particularly preferred for collecting and concentrating the agents to be detected and/or identified. The "dry" enzymes are not necessarily bone dry; oftentimes, perfect dryness is impractical because the preferred enzymes are hygroscopic proteins. However, it is neither necessary nor desirable for macroscopic amounts of water to be present, particularly when the fluid samples to be analyzed for agents are gaseous (e.g. air). When aqueous samples are analyzed, wetting of the enzyme can be and preferably is minimized, as explained in the discussion regarding FIG. 2 of the drawing. Typical dry enzymes used in detection elements of this invention have at least the appearance of substantially dry crystals, and the mechanism by which the crystalline enzyme interacts with fluid-borne agents (e.g. in air samples) is not fully understood.
By means of multiple internal reflection (MIR) infrared spectrophotometry, absorption spectra can be obtained for both dry, uncomplexed enzyme and the dry complex Enz-Inhib. In one embodiment of this invention, reliable model spectra--or portions of spectra--are obtained in advance and stored (e.g. in digital form) in a computer memory to provide a basis for comparison and/or to provide an internal standard or baseline. If desired, a model spectrum can be obtained at a given time (e.g. in the morning) from the dry immobilized cholinesterase layer on a dosimeter badge. When stored in a computer memory, this model can then be compared to the vary same cholinesterase layer after several hours of exposure, e.g. in the early evening of the same day that the "model" was obtained.
Reference or model spectra or baselines for comparison can also be obtained simultaneously with analysis of an exposed dosimeter or air sample by techniques such as beam splitting (using a commom broad- or narrow-spectrum infrared energy source), attenutation of reference beams, passing the reference beam through an uncomplexed dry enzyme "blank", and the like. When air is being sampled directly (e.g. with a real-time air monitor or alarm device), an air pump is normally used so that the volume of air passing over the detection element (which can contain a layer of dry, immobilized enzyme) in an eight-hour period will be very large. If the infrared energy source is omnidirectional and broad in its spectrum (e.g. a heated black body), specific bands can be selected with a prism or grating, as is known in the art. It is also known in the art that suitably "pumped" crystals (e.g. lasers) can produce narrow-spectrum or even monochromatic infrared radiation, thereby greatly simplifying the optics of the detection system, since in most cases one or two or three very narrow bands will be sufficient for both detection and identification of various agents. As noted previously, as few as two infrared bands can be sufficient to distinguish closely related agents which might otherwise interfere with each other in a single-wavelength analysis. Quantitative measurements (e.g. % absorption) can add the further dimension of roughly estimating a cumulative dose or determining when a dose has gone beyond a previous peak level.
This invention contemplates several different types of infrared analysis devices, the three general types described below being illustrative.
(a) A dosimeter badge "reader", which has an MIR (multiple internal reflection) crystal and a simple computer capable of storing the readings. (The badge includes a layer of dry enzyme immobilized on a flat surface which can be pressed against the MIR crystal.) The computer stores the model spectrum data, typically complete spectra or at least several preselected wavelengths. The stored daily readings can be calibrated against the model data; hence daily and cumulative exposure can be determined for at least one or two and preferably several agents.
(b) A real-time alarm, in which the enzyme for collecting the agent is in an element of the detection device itself, albeit a replaceable element, e.g. a coating on a replaceable transmission window or MIR crystal. Typically the alarm is designed to be triggered by only one or two agents, and a very few narrow bands or even a single band of infrared energy would be sufficient to detect a dangerous rise in nerve agent concentration in the atmosphere. (Sampled ambient air may be heated, cooled, dried, filtered, or the like to optimize sensitivity, and an air pump can be used to provide a large sample.) When the ambient concentration of nerve agent is zero or at a known level, the alarm device can be "zeroed" at the pre-selected wavelength or wavelengths, so that any decrease in percent absorption at a critical wavelength will activate the alarm. A computer, if included in this device at all, could be of the simplest type, e.g. a microprocessor chip.
(c) A detection/identification instrument, which would also include dry enzyme as an element, but with computer capabilities to identify and quantitate agents. An air pump would again be desirable for large air samples.
Turning now to the Drawing, wherein like numerals denote like parts in both Figures, detection device 10 of FIG. 1 includes three monochromatic infrared light sources 11, 12 and 13, which can beam essentially a single wavelength of infrared light through a transparent window 25 and into a multiple internal reflection (MIR) crystal 15. In the embodiment of the detection device shown in FIG. 1, only one of the three infrared energy sources is in use, i.e. source 11, but the three sources 11, 12 and 13 can be used either simultaneously or seriatim, as desired. Another characteristic of the device shown in FIG. 1 is that dry, immobilized enzyme (e.g. AChE or BuChE), has been formed into an immobilized dry layer 17 on a surface of MIR crystal 15. Thus, layer 17 is an element of the device of FIG. 1. If layer 17 becomes unduly "aged" or degraded, it can be replaced with a new layer. (In a dosimeter reader of this invention, the dry enzyme would not be a element of the device but would be instead an element of, for example, a dosimeter badge, not shown, which can be pressed against an MIR crystal.) Absent the enzyme layer 17, the beam 31 from energy source 11 would simply pass through crystal 15 with little or no absorption taking place, and the beam as it exits from the crystal and passes through transparent window 25 would be of approximately the same intensity as the beam entering the crystal. But the enzyme layer 17, after multiple internal reflection, absorbs at least some infrared energy resulting in a more atenuated beam 33 exiting from sample compartment 21 and being measured for percent absorption in spectrophotometric measurement means 35.
Sample compartment 21 is provided with an air pump 19, so that the flow of air over enzyme layer 17 will be voluminous in a given period of time, say, eight hours. The air flow exits through exit port 29.
The device shown in FIG. 1 has both a detection and identification capability. The monochromatic energy sources 11, 12 and 13 provide coherent beams of energy of, for example, 750, 950, and 1650 cm -1 . Computer 37 has stored in its memory the percent absorption for a suitable enzyme (e.g. a cholinesterase) at 1650 cm -1 , a peak in the infrared spectrum of the enzyme which does not change, even if the enzyme has complexed with a nerve agent or an organophosphorus compound. Accordingly, the computer 37 can compare the output of the spectrophotometric measuring means 35 (shown in the Figure to be measuring the percent absorption of beam 31 having a wavelength of, for example, 750 cm -1 ) with the 1650 cm -1 peak stored in its memory and determine whether or not there has been any change in percent absorption at the wave length of beam 31, using the stored information as a type of baseline. The output 39 from the computer 37 can be, for example, a digital readout which can be understood by the trained operator of device 10. Typically, the operator can thereby learn not only of the existence of the agent in the air sample but also of the identity of the agent. If there is the possibility of more than one agent producing the readout observed by the operator, a second wavelength provided by monochromatic energy source 12 can be consulted for further identification purposes. Alternatively, output 39 from computer 37 can simply operate an alarm when the transmission of beam 31 through crystal 15 falls below a certain level.
The device shown in FIG. 2 works in a manner exactly analogous to the device of FIG. 1 except that means have been provided to analyze liquid samples. The liquid sample is pumped through the upper portion of sample compartment 21 and out through exit port 29 much as in the device of FIG. 1, except that a selectively permeable membrane 51 has been provided to permit the agent to pass through membrane 51 and complex with enzyme layer 17 without permitting any significant amount of water to create problems for the infrared analysis. Thus the beam 31 impinging upon crystal 15 would not penetrate to the water flow and would be relatively uneffected by moisture present in the system.
In both FIGS. 1 and 2, the reference peak stored in the memory of computer 37 is a quantified portion of a model spectrum (hence a model percent transmission) of a model sample of the type of enzyme used in layer 17, the model portion of the spectrum having been measured under conditions substantially identical to the conditions under which devices 10 and 20 operate, and in a more complicated version of the devices 10 and 20 (not shown in the Drawing), the entire spectrum of layer 17 can be analyzed and compared to a complete model spectrum or curve stored in the memory of computer 37. In any event, the operation of devices 10 and 20 is premised upon the computer storage of a model percent transmission of a model sample of the enzyme in an uncomplexed state, which model percent transmission was measured under the aforementioned conditions.
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The disclosed methods and devices for detecting or monitoring or identifying substances (such as chemical warfare agents) and residual environmental pollutants (such as pesticides) utilize the discovery that spectra (e.g. infrared absorption spectra) of an uninhibited enzyme (e.g., a cholinesterase) can differ from spectra of the same enzyme which has been complexed with the agent pollutant. For example, the infrared spectrum of uninhibited butyrylcholinesterase (BuChE) lacks a distinct absorption peak found at about 1000 cm -1 in the BuChE-Malathion spectrum. The enzyme is used to collect and concentrate the agent or pollutant, and the resulting complexed enzyme can then be analyzed (e.g., by infrared spectroscopy) and its spectrum compared to an uninhibited enzyme spectrum.
Relatively simple devices can carry out the collection and detection or monitoring or identification steps of this invention, given appropriate models of complexed and uncomplexed enzyme specta upon which to base the design of the devices.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the US National Stage of International Application No. PCT/EP2010/067990, filed Nov. 23, 2010 and claims the benefit thereof. The International Application claims the benefits of German application No. 10 2010 008 811.0 DE filed Feb. 22, 2010 and German application No. 10 2010 023 542.3 DE filed Jun. 11, 2010. All of the applications are incorporated by reference herein in their entirety.
FIELD OF INVENTION
[0002] The invention relates to a plant for obtaining in-situ a carbonaceous substance from an underground deposit while reducing the viscosity thereof. Such an apparatus is used in particular for extracting bitumen or extra-heavy oil from a reservoir under a capping, such as that found in incidences of oil shale and/or oil sand in Canada, for example.
BACKGROUND OF INVENTION
[0003] In order to allow the extraction of extra-heavy oils or bitumen from the known incidences of oil sand or oil shale, their flowability must be significantly increased. This can be achieved by increasing the temperature of the incidence (reservoir). The increase in flowability can be achieved either by introducing solvents or thinners and/or by heating or fusion of the extra-heavy oil or bitumen, for which purpose heating is effected by means of pipe systems that are introduced through boreholes.
[0004] The most widespread and commonly used in-situ method for extraction bitumen or extra-heavy oil is the SAGD (Steam Assisted Gravity Drainage) method. In this case, steam (to which solvents may be added) is forced under high pressure through a pipe which runs horizontally within the layer. The heated fused bitumen or extra-heavy oil, once separated from the sand or rock, seeps down to a second pipe which is laid approximately 5 m deeper and via which the extraction of the liquefied bitumen or extra-heavy oil takes place, wherein the distance between injector and production pipe is dependent on the reservoir geometry.
[0005] The steam has to perform several tasks concurrently in this case, specifically the introduction of heat energy for the liquefaction, the separation from the sand, and the build-up of pressure in the reservoir, in order firstly to render the reservoir geo-mechanically permeable for bitumen transport (permeability), and secondly to allow the extraction of the bitumen without additional pumps.
[0006] The SAGD method starts by introducing steam through both pipes for e.g. three months, in order firstly to liquefy the bitumen in the space between the pipes as quickly as possible. This is followed by the introduction of steam through the upper pipe only, and the extraction through the lower pipe can commence.
[0007] The German patent application DE 10 2007 008 292 A1 already specifies that the SAGD method normally used for this purpose can be complemented by an inductive heating apparatus. Furthermore, the German patent application DE 10 2007 036 832 A1 describes an apparatus in which provision is made for parallel arrangements of inductors or electrodes, which are connected above ground to a converter.
[0008] The earlier German patent applications DE 10 2007 008 292 A1 and DE 10 2007 036 832 A1 therefore propose inductive heating of the deposit in addition to the introduction of steam. If applicable, resistive heating between two electrodes can also be effected in this case.
[0009] In the cited earlier patent applications, individual inductor pairs comprising forward and return conductors, or groups of inductor pairs in various geometric configurations, are subjected to current in order to heat the reservoir inductively. In this case, a constant distance between the inductors is assumed within the reservoir, resulting in a constant heating power along the inductors in the case of homogenous electrical conductivity distribution. In the description, the forward and return conductors are guided in close spatial proximity in the sections in which the capping is breached, in order to minimize the losses there.
[0010] As described in the earlier applications, variation of the heating power along the inductors can be effected specifically by sectional injection of electrolytes, thereby changing the impedance. This requires corresponding electrolyte injection apparatus, whose installation can be resource-intensive and costly.
SUMMARY OF INVENTION
[0011] Taking this as its starting point, the invention addresses the problem of further optimizing the above-described entity for inductive heating.
[0012] The problem is solved according to the invention by the features in the independent patent claims. Advantageous developments and embodiments of the invention are specified in the subclaims.
[0013] According to the invention, an apparatus is provided for extracting a substance containing hydrocarbons, in particular bitumen or extra-heavy oil, from a reservoir, wherein the reservoir can be subjected to thermal energy in order to reduce the viscosity of said substance, for which purpose at least one conductor loop for inductively applying current is provided as an electric/electromagnetic heater of the reservoir, wherein a pressurization means, in particular a pump, is provided for the purpose of injecting a liquid into the reservoir in liquid form, wherein a processing entity extracts the liquid that is to be injected from a reservoir liquid that is taken from the reservoir or from a medium that is taken from the reservoir, e.g. saline water, groundwater or a water-oil mixture, these including in each case enriched solids such as clay, lime and sand in particular.
[0014] In this case, the processing entity is provided in particular to ensure that an operating pump is protected and that there are no obstacles or blockages, particularly in relation to holes and slots in an injection pipe, when introducing the liquid that is to be injected.
[0015] The supply of the liquid—in liquid form and not as steam—is preferably effected via a liquid-carrying conduit, wherein a conductor—an inductor—of the conductor loop is surrounded by a liquid-carrying conduit in at least one section.
[0016] In this case, “inductive application of current” is understood to be in particular the application of a current source or voltage source to the conductor loop, thereby allowing an inductive supply of energy into the reservoir.
[0017] The pressurization means is provided for the purpose of introducing the liquid into the liquid-carrying conduit at high pressure.
[0018] The extraction of the liquid from the reservoir liquid or the medium is effected in particular by means of chemical and/or mechanical and/or thermal treatment of the reservoir liquid or medium. The processing entity preferably contains—as a conclusive list—merely an oil/gas separation entity, a sand removal entity and a desalination entity, in particular merely an oil/gas separation entity and a sand removal entity. These entities are preferably connected one behind the other in series.
[0019] The invention therefore relates to “in-situ” extraction, i.e. the extraction of the substance containing hydrocarbons directly from the reservoir in which this substance is enriched, without working the reservoir in the open. A reservoir is understood preferably to be an oil sand deposit that is situated underground.
[0020] The invention relates to the introduction of a liquid in liquid form, wherein the liquid does not have to be supplied entirely from outside, but is extracted in a largely closed circuit from the reservoir itself.
[0021] The invention does not discuss the introduction of steam into the reservoir. In particular, no provision is made for introducing steam via the liquid-carrying conduit that surrounds the conductor. A combination which additionally features the SAGD method can be advantageous, however, e.g. if supplementary steam is introduced via a further pipe or a further tube.
[0022] A section of the conductor is understood to be a partial length of the conductor. Assuming that the conductor is essentially a twisted cable which is encased by a pipe-shaped sleeve, a section of the conductor is understood to be a partial length along the extent of the cable and the sleeve.
[0023] A conductor is understood in particular to be a serial resonance circuit or part thereof, which is provided in a cable-type structure with external insulation. According to the invention, this is surrounded by a liquid-carrying conduit.
[0024] The liquid-carrying conduit is understood to be an extended hollow body, e.g. a pipe or a tube, through which liquid can be transported.
[0025] As a result of providing a liquid-carrying conduit, a liquid can be carried along the conductor and into the reservoir. Depending on the embodiment of the liquid-carrying conduit, the following advantages can be derived:
[0026] i) Increased electrical conductivity in the reservoir due to the introduction of liquid into the reservoir.
[0027] One of the problems that occurs in the context of electromagnetic heating by means of inductors in many deposits is specifically that the electrical conductivity in the deposit can be relatively low, such that the resulting thermal power that is introduced into the deposit may be inadequate, or even that high energy losses occur in the immediate environment of the deposit due to the significant penetration depths of the magnetic fields. An increase in the electrical input power, which would significantly compromise the profitability and the environmental friendliness of the process, can therefore be avoided according to the invention.
[0028] ii) Increased displacement of the substance containing hydrocarbons, e.g. the oil, due to the introduction of liquid into the reservoir.
[0029] A further problem that occurs in the context of electromagnetic inductive heating is specifically the incomplete or inadequate displacement of the oil from the deposit during the extraction, wherein this can adversely affect the extraction rate or even bring the extraction to a standstill. Using the SAGD method according to the prior art, the oil displacement occurs as a result of the expansion of the steam chamber in the deposit. Without the additional introduction of steam, a steam chamber is not necessarily present when the inventive electromagnetic inductive heating is used, and therefore oil displacement due to a steam chamber cannot take place. This could only be achieved by introducing a very high electrical power via the inductors, though this should preferably be avoided.
[0030] iii) Cooling of the conductor by virtue of the liquid being carried directly alongside or in the vicinity of the conductor, in order to counteract any heating of the conductor due to the heated environment of the conductor and/or to absorb any heat that has already accumulated in the conductor. Furthermore, it can be advantageous that the environment of the conductor can also be cooled in order to prevent boiling water in the reservoir from coming into direct contact with the conductor or its casing, wherein it should nonetheless be noted that boiling of water in the reservoir is generally advantageous in order to achieve a displacement of oil, for example.
[0031] As a result of cooling the conductor, the electrical conductivity in the immediate environment of the conductor can be reduced and therefore the geometry-related high heating power density can be reduced directly at the conductor. It is thus possible to achieve a more homogeneous heating power density in the reservoir.
[0032] The cooling is particularly advantageous at greater deposit depths, e.g. more than 130 m, because overheating of the inductor could otherwise occur, e.g. at temperatures of approximately 200° C. or more. In particular, plastic insulation of the inductor could not lastingly withstand such a high temperature. It should be noted here that the boiling temperature of water in the reservoir at a depth of 130 m or more can be approximately 200° C.
[0033] The heat of the conductor includes heat resulting from ohmic losses in the conductor, but the heat from the reservoir, which the conductor would absorb from the reservoir without corresponding cooling from the environment, can be more significant.
[0034] The pipe wall heat is advantageously carried away as a result of the liquid being in contact with a pipe wall, which itself is in contact with the reservoir.
[0035] Further Joulean losses in the conductor can dissipate into the liquid via the outer insulation of the conductor, wherein said outer insulation is in contact with the liquid and the liquid is carried in an outer pipe.
[0036] In the following, the features for cooling the conductor are explained first. The inventive idea here is based essentially on a liquid-carrying conduit comprising a closed liquid circuit, wherein cool liquid flows along the conductor within the liquid-carrying conduit, is heated up in the reservoir, and is then carried out of the reservoir again. The additional inventive idea is then explained on the basis of the above, wherein in addition to or as an alternative to the cooling, the liquid is fed via the liquid-carrying conduit into the reservoir, where it is distributed in the ground in order to achieve further effects, e.g. improving the conductivity in the reservoir.
[0037] 1) Cooling the conductor:
[0038] In a preferred embodiment, the liquid-carrying conduit and the conductor can be so arranged relative to each other that a liquid in the liquid-carrying conduit has a cooling effect on the conductor. In this case, it is irrelevant whether this is waste heat from the conductor itself or heat that acts on the conductor from the outside, i.e. from the reservoir that has been heated up by the conductive conductor. The cooling effect can be boosted by moving the liquid, in particular along the conductor while recirculating or exchanging the liquid, since this allows warm liquid to be carried away and cool liquid to flow in.
[0039] In a further advantageous embodiment, the liquid-carrying conduit can be part of a largely closed liquid circuit, wherein provision is made for a heat exchange means, in particular at the surface and not within the reservoir, in order to cool down a liquid that has been heated up within the liquid-carrying conduit.
[0040] By means of a further advantageous embodiment, the recooling of the liquid can be done by means of pipes that lead through a colder region of the reservoir, i.e. the liquid is not brought to the surface but merely circulates deep underground. In this case, provision is preferably made for installing a pump deep underground. In this case, the heating power that has been electrically introduced is advantageously not removed from the reservoir but is merely distributed differently.
[0041] The liquid-carrying conduit can advantageously be embodied as a tube and/or pipe, wherein the conductor is arranged within the tube or the pipe, in particular such that a liquid flows around the conductor when said liquid is supplied. Optimal transfer of heat from the conductor to the liquid can be ensured thus.
[0042] In particular, the tube and/or the pipe can be arranged approximately coaxially—centered—relative to the conductor, wherein provision is made in particular for at least one ridge within the tube or the pipe for holding or positioning the conductor or for stabilizing the position of the conductor within the tube or the pipe. Further ridges can be provided in an axial direction of the tube/pipe, in order to secure the position of the conductor. Alternatively, a ridge can also feature an axial elongation, which even extends along the entire length of the tube/pipe in a specific embodiment.
[0043] Alternatively, the conductor can also be so arranged as to move freely within the tube or the pipe, i.e. the conductor is not centered in the tube or in the pipe and holding means are not provided.
[0044] In a further embodiment, the liquid-carrying conduit can be embodied as a multiplicity of tubes and/or pipes. Moreover, a multiplicity of capillaries and/or a porous material can be provided for the purpose of transporting the liquid in the liquid-carrying conduit. These variants are preferably arranged such that the conductor is surrounded by the multiplicity of tubes and/or pipes and/or capillaries and/or the porous material, wherein the multiplicity of tubes and/or pipes and/or capillaries and/or the porous material and the conductor are preferably arranged within a shared tubular outer sleeve. In particular, these cited means for carrying the liquid are all parallel to each other or twisted.
[0045] These embodiments can be understood to mean that the liquid does not flow directly around the conductor, but that tubes/pipes are externally attached to the conductor.
[0046] For the sake of completeness, it should be noted that a reverse approach is also conceivable here, whereby a conductor can be composed of a multiplicity of part-conductors and these part-conductors can be arranged around the liquid-carrying conduit.
[0047] In a development of the previous embodiments, the liquid-carrying conduit can be designed in the form of a multiplicity of tubes and/or pipes, such that provision is made for at least one first tube and/or pipe in which the liquid flows in an opposite direction to a flow direction of the liquid in a second tube and/or pipe, of which there is at least one. In this way, it is possible to form a closed circuit, for example. Alternatively, liquid could also be pumped into the liquid-carrying conduit from two locations above ground, wherein only a subset of the available tubes or pipes are replenished at each of the two locations. By virtue of a contra-rotating movement of liquid, a more homogeneous temperature is advantageously achieved along the conductor.
[0048] In a development of the invention, thermal insulation means can be arranged between the liquid-carrying conduit and the reservoir, in particular between the liquid-carrying conduit and the outer sleeve, wherein the thermal insulation means are designed in particular as a hollow space which is filled with air or gas or which encloses a vacuum. The thermal insulation of the liquid-carrying conduit relative to the reservoir is particularly advantageous in this case, since only the smallest possible portion of the inductively introduced heating power is then carried away again by the liquid cooling in the case of a suitable embodiment.
[0049] Provision can also be made for a pressurization means for increasing the pressure of a liquid or for circulating the liquid, in particular a pump, such that movement of the liquid in the liquid-carrying conduit is achieved by means of the pressurization means. A cooling circuit can be operated in this way.
[0050] Natural circulation possibly including a boiling process (e.g. thermosiphon) can also be provided as an alternative to the active pump.
[0051] Further elements of the overall system in addition to the liquid-carrying conduit and the pump can be in particular a container for the liquid, a heat exchanger and further overground or underground hydraulic connections. In this case, the container can be embodied for use at atmospheric pressure or as a pressure tank. Provision can also be made for a manostat, by means of which the liquid is maintained at higher pressure as a coolant and circulates at high pressure in order to prevent boiling as a result of a high power input. The overall system preferably features a return conduit for carrying the liquid to the surface.
[0052] In a particularly advantageous embodiment of the invention, the liquid-carrying conduit features a perforation such that when a liquid is supplied the liquid can pass into the reservoir from the liquid-carrying conduit, and the perforation in turn features holes which can be so configured in terms of shape and/or size and/or distribution that when a liquid is supplied at a predefined pressure the conductor is adequately cooled over the entire length of the conductor loop section that is surrounded by the liquid-carrying conduit.
[0053] In particular, this can be achieved by ensuring that the liquid-carrying conduit is continuously filled with sufficient liquid over its length and/or that liquid which has been heated by the conductor is conveyed out of the liquid-carrying conduit through the holes. Alternatively or additionally, a required quantity of low-temperature cooling liquid can subsequently flow through the liquid-carrying conduit.
[0054] The above cited effect is preferably produced when the pressure that is applied by means of the supply to the liquid in the liquid-carrying conduit is adapted to a predefined perforation in such a way that a discharge of the liquid through the perforation is ensured over an extended period of application.
[0055] The above described arrangements are particularly advantageous in that an environment in the reservoir is thermally insulated by virtue of the liquid that is carried through the liquid-carrying conduit and/or in that the conductor is cooled by the liquid that is carried through the liquid-carrying conduit.
[0056] Water can be provided as a liquid for cooling, in particular water that has been desalinated and/or decalcified and/or contains a frost protection means, e.g. glycol. Saltwater, oil, emulsions or solutions can also be provided.
[0057] The basic form of the liquid can preferably be an extracted liquid that can be separated from the desired extraction material that is extracted from the reservoir.
[0058] With regard to the cooling, it can be stated in summary that by virtue of the inventive arrangement, overheating of the inductor (which also represents a risk at greater depths) can be avoided and/or the service life can be extended in comparison with an uncooled inductor. The arrangement makes it possible to achieve higher and more cost-effective power densities.
[0059] The provision of a perforation in order thereby to achieve an injection of the (coolant) liquid into the reservoir is also advantageous because the heat that is carried away from the conductor remains in the reservoir and is not removed from the reservoir as in the case of a closed cooling circuit with recooling at the surface. The injection of the liquid into the reservoir is now described in greater detail below.
[0060] 2) Feeding liquid into the reservoir:
[0061] Excepting the fact that the following does not relate to a closed liquid circuit and that liquid in the reservoir is intentionally “lost”, the above cited features can also be implemented in an identical or similar manner when feeding the liquid into the reservoir. The resulting advantages (e.g. the improved cooling) are still produced correspondingly.
[0062] In an advantageous embodiment of the invention, the liquid-carrying conduit can be perforated such that, when a liquid is supplied, the liquid penetrates or is introduced into the reservoir from the liquid-carrying conduit. Perforation is understood to signify e.g. holes or slots that are located in a liquid-carrying conduit, such that liquid can escape from the interior of the liquid-carrying conduit outwards into the environment of the holes or slots. In addition to the cited holes and slots, the liquid-carrying conduit can also consist at least partly of porous material or capillaries, such that the liquid can be discharged into the environment via these means.
[0063] In this case, the introduction of the liquid into the reservoir can increase the electrical conductivity of the reservoir and/or the pressure in the reservoir.
[0064] As mentioned above, a pressurization means, in particular a pump, can be provided for the purpose of increasing the pressure of a liquid or circulating the liquid, such that a liquid can be introduced into the liquid-carrying conduit at a higher pressure using the pressurization means. In particular, the pump should be capable of generating so much pressure that a predefined quantity of liquid penetrates into the reservoir via the perforation. A “higher pressure” therefore means that an environmental pressure in the reservoir is to be overcome. The hydrostatic pressure in the reservoir must be exceeded in the environment of the perforation in order that the liquid can emerge, wherein this can be achieved at a pressure of e.g. 10,000 hPa (10 bar) to 50,000 hPa (50 bar).
[0065] The perforation can preferably be embodied and/or means can preferably be provided such that any ingress of solids and/or sand from the reservoir is largely prevented. For example, the term “gravel pack” is used to refer to such means.
[0066] In a particularly advantageous embodiment of the invention, the perforation features holes which can be so configured in terms of shape and/or size and/or distribution that when a liquid is supplied at a predefined pressure the liquid is discharged in a distributed manner along a length of the liquid-carrying conduit through the perforation into an environment of the conductor loop in the reservoir, such that the electrical conductivity of the reservoir is changed and/or the pressure in the reservoir is increased. In particular, the liquid can be controlled in such a way that the electrical conductivity within the reservoir is predominantly increased over the extent thereof, and/or that the electrical conductivity in the reservoir is lowered in the immediate environment of the conductor.
[0067] The perforation should preferably be designed such that the entire length of the liquid-carrying conduit, with the exception of the supply from the surface to the target region in the reservoir, discharges the same quantity of liquid in each section.
[0068] The pressure increase in the reservoir is particularly advantageous in that the substance containing hydrocarbons is consequently displaced more effectively in the reservoir, and/or an underpressure in the reservoir (due to the extraction of the substance) is consequently avoided.
[0069] The above cited effects, increasing the conductivity and increasing the pressure, are preferably produced when the pressure that is applied by means of the supply to the liquid in the liquid-carrying conduit is adapted to a predefined perforation in such a way that a discharge of the liquid through the perforation is ensured over an extended period of application.
[0070] Suitable liquids to be supplied include in particular water or an organic or inorganic solution as an electrolyte, in particular also for the purpose of increasing the conductivity.
[0071] The liquid can preferably comprise at least one of the following components: salts, weak acids, weak bases, CO 2 , polymers or solvents containing in particular alcanes such as methane, propane, butane, for example.
[0072] In order to further increase the pressure in the reservoir, a valve in an extraction pipe for removing the liquefied substance containing hydrocarbons from the reservoir can be closed, and subsequently opened as a function of a predefined time period being completed or a predefined pressure within the reservoir being reached. The pressure can therefore be increased during said time period because no material leaves the reservoir and additional liquid is introduced.
[0073] In particular, closing the liquid circuit is not necessary if a perforation is present in the liquid-carrying conduit. For example, two discrete liquid-carrying conduits can be provided for the conductor loop, one for each half of the conductor loop, wherein both of the liquid-carrying conduits terminate in the reservoir without the liquid being pumped back to the surface.
[0074] The composition of the liquid that is fed into the reservoir in liquid form has already been explained above. It is particularly advantageous here if the liquid is at least partially or even wholly extracted from the extracted mixture of water-oil and bitumen. To this end, the desired substance to be extracted should be separated from the extracted mixture of water-oil and bitumen, and the aqueous residue then processed or processed. This can nonetheless be effected far more easily than the injection of steam.
[0075] The mixture of water-oil and bitumen that is extracted can first undergo separation of oil and/or gas from the liquid can take place first. This results in a residual liquid—also called produced water—which still contains oil fractions, suspended matter and sand, and a multiplicity of chemical elements or compounds. However, removal of the remaining oil fraction or even of many chemical elements can now be omitted, since the residual liquid that is fed back into the reservoir only contains substances that were previously already present in the reservoir and flushed out during the extraction. It is also possible to dispense with the generation of feed-water quality, since the liquid is re-injected in almost its original form and therefore resource-intensive treatment of the liquid is unnecessary.
[0076] The fact that the residual liquid is according to the invention introduced into the reservoir in liquid form and not in a gaseous state is another reason why further reprocessing of the residual liquid is unnecessary. Extraction of feed water for steam generators would require an expensive apparatus and significant energy consumption, however.
[0077] Processing of the residual liquid should mainly include sand separation, since this can lead to blocking and sanding up of the liquid-carrying conduit when the residual liquid is fed back into the reservoir. This would hamper continuous operation.
[0078] In an advantageous embodiment, desalination of the residual liquid can also be performed after the sand removal, in order to prevent an excessive salt concentration in the reservoir as a result of continuous introduction of the processed residual liquid.
[0079] As a result of introducing the residual liquid after desalination and sand removal, the viscosity within the reservoir can be reduced, i.e. the flow properties of bitumen can be improved. It also results in an increase in the stability of the reservoir.
[0080] In addition to the cited components, a heat exchanger can also be provided for the purpose of bringing the processed residual liquid up to a higher temperature, in order thereby to prevent unwanted cooling of the reservoir and a resulting pressure drop or increase in viscosity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0081] The present invention and its developments are explained in greater detail below in the context of an exemplary embodiment and with reference to figures providing schematic illustrations, in which:
[0082] FIG. 1 shows an apparatus in which an inductor is cooled;
[0083] FIG. 2 shows a perspective illustration of a cooled inductor;
[0084] FIGS. 3 , 4 , 5 , 6 show cross sections of various inductors with a liquid-carrying conduit;
[0085] FIG. 7 shows a perforated liquid-carrying conduit;
[0086] FIG. 8 shows an apparatus for injecting a liquid into the reservoir;
[0087] FIG. 9 shows an apparatus for processing and injecting an extracted production flow.
DETAILED DESCRIPTION OF INVENTION
[0088] Corresponding parts in the figures are denoted by the same reference signs in each case. Parts that are not explained in greater detail are known generally from the prior art.
[0089] FIG. 1 shows a schematic illustration of an apparatus for obtaining in-situ a substance containing hydrocarbons from an underground deposit 6 (reservoir) while reducing the viscosity thereof, provision being made for cooling of inductors 10 . Such an apparatus can be e.g. an apparatus for obtaining bitumen from an incidence of oil sand. The deposit 6 can be in particular an incidence of oil sand or oil shale from which bitumen or other heavy oils can be obtained.
[0090] Also illustrated is a pipe 9 for introducing steam, wherein said pipe 9 is essentially arranged between parallel sections of an inductor 10 within the reservoir 6 and is supplied via a steam generator 8 . The steam is forced into the reservoir 6 by means of nozzles (not shown) that are distributed along the length of the pipe.
[0091] The illustration does not include a production pipeline via which the substance extracted from the deposit 6 is collected and transported out of the deposit 6 to the surface 5 .
[0092] The apparatus for obtaining in-situ a substance containing hydrocarbons additionally features an inductor 10 that runs in boreholes within the deposit 6 . The inductor 10 or sections thereof constitute the conductor as described in the invention. A closed conductor loop is formed, consisting of the two (forward and return) conductors of the inductor 10 , these extending horizontally in the deposit, and of conductor pieces 11 that effect little or no heating and run above ground or from the surface 5 into the deposit 6 in order to provide the power connection for the inductor 10 . Both loop ends of the conductor loop are arranged above ground in the figure, for example. On the right-hand side of the figure, the loop is simply closed; see conductor piece 11 in the figure. On the left-hand side is an electricity supply 1 including any electrical entities such as voltage converters and generators that are required, and being used to apply the required current and the required voltage to the conductor loop, such that the inductors 10 are used as conductors for an electric/electromagnetic heater for generating heat in the deposit 6 .
[0093] The inductors 10 act as an inductive electrical heater in relation to at least parts of the deposit 6 . Due to the conductivity of at least parts of the deposit 6 , the latter can be heated largely concentrically around the two preferably parallel sections of the inductor 10 .
[0094] The heating power of the conductor loop can be significantly reduced by means of suitable routing in regions where it runs outside of the actual deposit 6 , e.g. in the conductor pieces 11 . In this way, the heating power can be introduced into defined regions of the deposit 6 . In particular, the inductor 10 can comprise rod-shaped metallic conductors or twisted metallic cables that are made of a particularly conductive metal and form a resonance circuit.
[0095] According to the figure, a cooling circuit for cooling the inductor 10 is provided in addition to the electrical circuit. The cooling circuit comprises a liquid-carrying conduit 12 that almost completely encases the length of the conductor loop as per the figure. Only the inductor 10 requires a casing. A casing is not necessary outside of the deposit 6 , though it may be advantageous since the liquid-carrying conduit 12 can then be installed jointly with the conductor loop, thereby allowing a simpler installation.
[0096] According to the figure, those sections of the cooling circuit which are not explicitly provided for the purpose of cooling are marked as liquid entry/exit lines 13 . According to the figure, the liquid circuit on the left-hand side is simply closed to form a ring, such that the liquid that is carried through a first liquid-carrying conduit 12 along a first section of the inductor 10 is carried back through a second liquid-carrying conduit 12 along a second section of the inductor 10 . The aboveground components for providing the liquid are shown on the right-hand side of the figure. Said components comprise a container 3 , in which the liquid 14 used for cooling is located. A pump 2 is also provided, for the purpose of pumping the liquid 14 into the cooling circuit and ensuring the flow speed. Provision is further made for a recooling unit 4 , by means of which the heated cooling liquid can be cooled down.
[0097] There are many conceivable variants with regard to the arrangement of the inductor and the cooling circuit. A further recooling unit could also be present on the left-hand side of the figure, for example. Furthermore, a plurality of cooling circuits could be present. Forward and return transport of the liquid could take place along a single section of the inductor 10 and not along the whole loop.
[0098] The liquid-carrying conduit 12 in the figure is designed as a coaxial casing of the inductor 10 , such that the inductor 10 —or a casing of the inductor 10 —is as far as possible fully surrounded by a cooling liquid during operation.
[0099] During live operation, the apparatus can therefore be operated such that when current is applied to the inductor 10 , thereby heating the environment of the inductor 10 in the deposit 6 , a cooling liquid is continuously carried through the liquid-carrying conduit 12 and along the inductor 10 . The inductor 10 heats the ground in the environment of the inductor 10 , whereby the heated ground itself becomes a thermal source. The inductor 10 must be protected against high temperatures. This is done by means of the cooling liquid in the liquid-carrying conduit 12 providing the external cooling of the inductor 10 as described above, whereby the inductor 10 is thermally insulated and the temperature absorbed by the inductor 10 is carried away again, such that the inductor 10 does not heat up, or at least only heats up slightly or to a small extent.
[0100] In order to improve this effect, the liquid-carrying conduit 12 can be additionally encased by a thermal insulator.
[0101] It is thus possible in particular to prevent any boiling of water directly against the inductor 10 in the deposit 6 , which would have a negative effect on an uncooled protective casing of the inductor 10 since the protective casing is provided for electrical insulation of the inductor 10 and normally consists of plastic, but a long-term increase in temperature could degrade the plastic. It should nonetheless be noted here again that boiling of liquid in the reservoir is entirely advantageous per se.
[0102] The inductor 10 is ideally integrated in the liquid-carrying conduit 12 and can be installed as a single unit. Various embodiments of such combined conductors and cooling elements are explained in the following.
[0103] FIG. 2 schematically shows a section of an inductor 10 with a surrounding a cooling element in a perspective illustration. An inductor 10 that is centrally arranged in a tubular casing 15 of the liquid-carrying conduit 12 is surrounded by a liquid-carrying conduit 12 . The positioning of the inductor 10 can be determined solely by the flowing liquid in the liquid-carrying conduit 12 . Centering is not provided according to FIG. 2 . To a large extent, the inductor 10 can therefore move freely in the liquid-carrying conduit 12 and could e.g. come to rest on the inner side of the liquid casing due to its weight. However, various embodiments are proposed below for specific positioning or holding in the liquid-carrying conduit 12 .
[0104] The diameter of the inductor 10 can preferably be 30-100 mm. The annular gap width of the inductor 10 is preferably 5-50 mm and the mass flow of the cooling medium within the liquid-carrying conduit 12 is preferably 5-100 l/min.
[0105] Cross sections of cooled conductors are illustrated schematically in the following. The cross section represents a plane of section as indicated by A-A in FIG. 1 .
[0106] According to FIG. 3 , a support of the inductor 10 takes the form of e.g. star-shaped spacers or ridges 16 , wherein two to five spacers are preferably used. However, a solution using only one ridge 16 is also conceivable. The ridges 16 are preferably attached to the inner wall of the casing 15 and are connected at the center by means of stabilizers 17 or attached directly to the outer sleeve of the inductor 10 . The inductor 10 is located coaxially at the center of the casing 15 of the liquid-carrying conduit 12 and is either installed as a unit with the casing 15 and the ridges 16 or is drawn through subsequently.
[0107] The liquid-carrying conduit 12 is created by the hollow spaces within the casing 15 .
[0108] In the case of ridges 16 that are embodied along the entire length, a plurality of chambers are formed at the same time between the ridges 16 , wherein the cooling liquid can flow in different directions through said chambers.
[0109] The width of the ridges 16 can be in the range of 5-30 mm, for example, such that the pressure losses of the cooling medium in the liquid-carrying conduit 12 do not become excessive.
[0110] As shown in FIG. 4 , a plurality of tubes or pipes 12 A, 12 B, . . . , 12 F are provided as a liquid-carrying conduit 12 in the annular gap (i.e. within an outer sleeve 20 ) around the inductor 10 . In this case, bidirectional transport of the cooling medium in the tubes/pipes is conceivable. In addition, a thermal insulator 18 between the tubes/pipes and the outer sleeve 20 can also be used, either as part of the outer sleeve 20 or as a separate element. This is also understood to mean that these intermediate spaces can remain empty, i.e. air or a specific gas or a vacuum can be used for thermal insulation.
[0111] The thickness of a thermal insulating layer can preferably be between 3 and 50 mm.
[0112] In FIG. 5 , the cooling medium is carried via capillaries 19 as a liquid-carrying conduit 12 . Alternatively, a porous material can be used for this purpose. In particular, these variants have the advantage that the liquid flow within the liquid-carrying conduit 12 can be controlled more effectively and the position of the inductor 10 relative to the liquid-carrying conduit 12 can be predetermined exactly. This can be advantageous since the induced field does not have the same strength on all sides of the inductor 10 , depending on the alignment of the two inductors 10 relative to each other.
[0113] For the sake of completeness, FIG. 6 illustrates a further variant of the liquid cooling, in which a central tube or pipe carrying the cooling medium as a liquid-carrying conduit 12 is surrounded by the part-conductors 10 A, 10 B, . . . , 10 F. The part-conductors 10 A, 10 B, . . . , 10 F together represent the inductor 10 in this case. In this embodiment, the tube diameter or pipe diameter of the liquid-carrying conduit 12 can preferably be between 10 and 100 mm and the mass flow of the cooling medium can be between 5 and 100 l/min. The inductor 10 can consist of e.g. 10-2000 part-conductors, whose total cross-sectional area is typically 10-2000 mm 2 .
[0114] While mere transportation of cooling liquid is described above, this is combined in the following with a means of discharging liquid into the deposit 6 along the length of the liquid-carrying conduit 12 .
[0115] FIG. 7 schematically shows a section of an inductor 10 with a surrounding cooling element in a perspective illustration, wherein a liquid-carrying conduit 12 is designed to be perforated such that liquid can escape, wherein the liquid can actually escape in liquid form or possibly also as gas, e.g. steam.
[0116] In a similar manner to FIG. 2 , an inductor 10 that is centrally arranged in a tubular casing 15 is surrounded by a liquid-carrying conduit 12 . Unlike the embodiment in FIG. 2 , the liquid-carrying conduit 12 or the casing 15 features a perforation 12 consisting of a multiplicity of holes and outlets, through which the transported liquid can penetrate from the interior to the exterior. The size, position and frequency of the holes must be adapted to the desired conditions in this case, and should not be interpreted restrictively from the illustration in FIG. 7 , in particular such that e.g. 30-300 l/min can escape along the entire length of the liquid-carrying conduit 12 .
[0117] The holes of the perforation 21 can be arranged symmetrically around the overall circumference of the casing 15 in this case. However, an unequal distribution can also be advantageous. The distribution and/or the embodiment of the holes can also change over the length of the liquid-carrying conduit 12 , in particular since the pressure within the liquid-carrying conduit 12 can change as a result of the escaping liquid.
[0118] In this case, liquid escaping into the deposit 6 in the environment of the inductor 10 is advantageous to the extent that an electrolyte can be injected into the reservoir in this way, thereby allowing the electrical conductivity in the deposit 6 to increase and producing a higher pressure within the deposit 6 . Both effects allow an increase in the extraction quota and/or the extraction speed of the substance containing hydrocarbons that is to be extracted. Further explanations relating to this are given with reference to FIG. 8 .
[0119] The layout of FIG. 8 corresponds essentially to that of FIG. 1 . Provision is made for a conductor loop that is operated by an electricity supply 1 . Sections functioning as electrodes are highlighted as inductors 10 . These are the sections that run horizontally in parallel in the deposit 6 .
[0120] Also present is a container 3 for providing a liquid 14 that is intended as a cooling liquid. This liquid 14 is introduced by means of the pump 2 into a liquid system consisting of the liquid entry lines 13 and the liquid-carrying conduit 12 . The liquid-carrying conduit 12 is again intended to represent the sections running horizontally and in parallel in the deposit 6 . The liquid entry lines 13 comprise the tube/pipe system above the ground 5 and the connection to the horizontal liquid-carrying conduit 12 .
[0121] Unlike FIG. 1 , the supply in the present example is effected from the left-hand side of the drawing, though a supply from the right-hand side as in FIG. 1 is also possible. A more significant difference relative to FIG. 1 is however that in the horizontal underground section the liquid-carrying conduit 12 has a perforation 21 via which liquid 22 escapes as indicated by arrows. Moreover, the liquid-carrying conduit 12 in the present example already terminates underground. A seal 23 of the liquid-carrying conduit 12 is provided for this purpose, wherein said seal can likewise feature a perforation.
[0122] Contrary to the present embodiment, it is however also conceivable for the liquid-carrying conduit 12 to be routed back to the surface for a remaining liquid residue. Alternatively, it is possible for the liquid-carrying conduit 12 to be routed back to the surface, but for no liquid to reach the surface 5 due to the pressure ratios. The last section of the liquid-carrying conduit 12 would therefore contain no liquid.
[0123] Liquid is introduced into the cooling system during operation by means of a pump 2 or an apparatus functioning in a similar manner. The pressure remains largely unchanged as far as the liquid-carrying conduit 12 , since no liquid outlet is provided until the start of the liquid-carrying conduit 12 . When the supplied liquid reaches the section featuring the inventive liquid-carrying conduit 12 , a portion of the liquid is introduced into the deposit 6 via the perforation 21 . A further portion of the liquid flows further along the liquid-carrying conduit 12 , wherein liquid is continuously discharged via the perforation 21 . An outflow of the liquid is therefore produced as a result of the escaping liquid 22 . The loss of liquid is replaced via the pump 2 by top-up liquid.
[0124] A number of effects are therefore produced: firstly the liquid flows along the inductor 10 and can carry heat away. Secondly the liquid flows into the deposit 6 in the vicinity of the inductors 10 , whereby the pressure in the deposit 6 can be increased or a pressure that is falling off due to the extracted of the substance containing hydrocarbons can be equalized, and the electrical conductivity in the deposit 6 can be increased in the vicinity of the inductors 10 in particular, which in turn increases the efficiency of the inductors 10 . The cited effects are mutually influential, since the discharge of the heated liquid into the environment of the inductor 10 causes cool liquid to subsequently flow along the inductor 10 within the liquid-carrying conduit 12 , thereby maintaining the cooling or thermally insulating effect.
[0125] The seal 23 , the dimensions of the liquid-carrying conduit 12 , the embodiment of the perforation 21 and the pressure that is applied to the liquid via the pump 2 should preferably be adapted to each other, giving particular consideration to the available rock information and the depth of the deposit, such that to a large extent the cited effects occur and/or liquid 22 escapes evenly into the deposit 6 over the entire length of the horizontally oriented inductor 10 .
[0126] The pressure is dependent on the depth of the deposit, i.e. on the distance of the horizontally laid inductors 10 from the surface 5 . The pressure should be greater than the hydrostatic pressure of the corresponding water column and lies in the range between 10,000 hPa (10 bar) and 50 , 000 hPa (50 bar), for example.
[0127] Pressure relief in the deposit 6 is effected by opening the production pipe(s) (not shown) at such time as the pressure on a capping above the deposit 6 becomes excessive. However, it can be advantageous to keep the production pipes closed for as long as possible in order to achieve a high pressure.
[0128] The function of the escaping liquid 22 is therefore both to increase or maintain the pressure in the deposit 6 and to displace (flush out) the substance that is to be extracted, thereby also preventing underpressure in the deposit 6 .
[0129] In particular, the liquid can be an electrolyte such as water or an aqueous solution, e.g. mixed with other constituents. In particular, the electrolyte, displacer or solvent can comprise organic or inorganic liquids, gases in a different state of aggregation, or combinations thereof, in particular water (preferably production water that has been separated from heavy oil), saltwater, weak acids, weak bases, other solvents such as methane, propane, butane, CO 2 , or mixtures thereof.
[0130] The cross sections shown in the FIGS. 2 to 5 are also applicable in the case of a liquid-carrying conduit 12 from which liquid 22 escapes.
[0131] According to the embodiment in FIG. 2 , the inductor 10 can be located in a perforated injector pipe/tube in which no provision is made for centering the inductor 10 . The diameter of the inductor 10 is preferably 30-100 mm. The annular gap width is preferably 5-50 mm and the mass flow of the cooling medium is preferably 30-300 l/min.
[0132] According to FIG. 3 , the inductor 10 is located in a perforated injector pipe/tube, wherein support for the inductor 10 is provided by star-shaped spacers. The diameter of the inductor 10 is preferably 30-100 mm. The annular gap width is preferably 5-50 mm and the mass flow of the cooling medium is preferably 30-300 l/min.
[0133] According to FIG. 4 , one or more perforated injector pipes/tubes are attached to the inductor 10 . The direct contact between the inductor 10 and the reservoir is provided. Omission of the contact can even be advantageous, since the heat transfer from the surrounding hot reservoir back onto the inductor 10 is reduced. The diameter of the inductor 10 is preferably 30-100 mm. The diameter of the adjacent pipes is preferably 5-50 mm and the mass flow of the cooling medium is preferably 30-300 l/min.
[0134] In the case of the embodiment described in FIG. 8 , it is advantageous in particular that more cost-effective and higher power densities can be achieved. It is possible at the same time to prevent overheating of the inductor 10 (which also represents a risk at greater depths) and to achieve additional displacement of the substance that is to be extracted from the deposit. Moreover, deposits having limited electrical conductivity can only be inductively heated as a result of this liquid being fed into the deposit.
[0135] In contrast with FIG. 8 , the apparatus in a further implementation variant can be embodied such that only partial regions of the inductor 10 are located in an injector pipe/tube. Moreover, the discharge holes of the perforation 21 can be distributed unevenly or provision can be made for sections in which there is no perforation 21 .
[0136] With regard to the embodiments cited above, it is again noted that no provision is primarily made for supplying steam which is generated above ground, but that provision is made for supplying liquids. Even a supplementary input of steam is preferably omitted.
[0137] In the case of the foregoing embodiments, further details have not been provided in respect of possible sources of the liquid that is to be introduced into the liquid-carrying conduit. With reference to FIG. 9 , it is now explained that this liquid can be wholly or partly extracted from the production flow.
[0138] FIG. 9 schematically shows a cutaway of a deposit 6 , wherein said deposit 6 is disposed below the surface of the earth 5 and contains a region 7 that features an incidence of oil. A conductor loop is provided as in the previous embodiments, wherein only one inductor 10 of the conductor loop is illustrated in FIG. 9 .
[0139] In addition, the inductor 10 is encased at least partially by a liquid-carrying conduit 12 . The conductor loop is operated by an electricity supply 1 as in the previous embodiments.
[0140] Although this is not illustrated in the FIGS. 1 and 8 , a production pipe 39 for transporting away the substance to be extracted is provided in the ground in all embodiments of the invention. The production pipe 39 allows a production flow 30 in the form of a liquid-solid-gas mixture (i.e. a phase mixture) to be transported to the surface 5 for processing.
[0141] The substance to be extracted is firstly separated from the liquid-solid-gas mixture by means of an oil/gas separator 31 . Separated oil 32 resulting therefrom is indicated in the figure as an arrow, as is a separated gas 33 that is alternatively or additionally produced. There remains a residual liquid 34 (produced water) of the separated production flow 30 , which residual liquid 34 then undergoes further processing so that it can subsequently be injected into the deposit 6 in liquid form.
[0142] As a first processing step, the residual liquid 34 is supplied to a sand removal entity 35 , in which sand and other solids are removed. This processing step results in a sand-free residual liquid 36 .
[0143] As a result of removing the sand, the remaining sand-free residual liquid 36 already has a consistency that is suitable for re-injecting in liquid form. By virtue of the sand-free residual liquid 35 , a pipe that is used for re-injection can obviously be operated over the long-term without becoming blocked or sanded up.
[0144] A further processing step takes place according to FIG. 9 . The sand-free residual liquid 36 is supplied to a desalination entity 37 , which reduces the salt content of the sand-free residual liquid 36 . This can be achieved by adding specific chemicals. A salt content corresponding to a natural salt content within the deposit 6 is ideally achieved in the resulting processed liquid 38 by virtue of the desalination entity 37 .
[0145] Further processing steps can be omitted, since provision is inventively made for introducing a liquid (in liquid form and not as a gas) into the deposit 6 and along the inductor 10 by means of the liquid-carrying conduit 12 . The processing can therefore be restricted to sand removal and desalination.
[0146] The liquid 38 thus processed can then be supplied into the cooling circuit as per FIG. 1 or supplied to the liquid injection facility as per FIG. 8 . A further alternative variant is explained below with reference to FIG. 9 .
[0147] According to FIG. 9 , the processed liquid 38 is supplied to a pump 2 and forced under pressure into the liquid entry line 13 , which subsequently merges into the liquid-carrying conduit 12 . The inductor 10 is again guided within the liquid entry line 13 and the liquid-carrying conduit 12 . The previously described embodiments of the inductor within a liquid-carrying conduit remain valid, in particular the embodiments according to the FIGS. 2 to 4 . For example, FIG. 9 illustrates an embodiment in which the inductor 10 is held by means of ridges 16 that are sectionally present within the liquid-carrying conduit or entry line.
[0148] The processed liquid 38 is therefore introduced deep into the deposit 6 inside a tube or pipe along the inductor 10 within the liquid entry line 13 and the liquid-carrying conduit 12 . In order that the liquid 38 can then be injected into the soil of the deposit 6 over a greater length, the liquid-carrying conduit 12 is slotted such that the liquid 38 can penetrate via slots 40 from the liquid-carrying conduit 12 into the subsoil.
[0149] The penetrating liquid can vaporize there over time due to the heating effect of the inductor 10 .
[0150] According to FIG. 9 , the length of the liquid-carrying conduit 12 is limited and terminates, while the inductor 10 continues horizontally onwards. The length of the slotted liquid-carrying conduit 12 , the frequency and the size of the slots 40 , and the quantity of the liquid 38 that is forced in should be coordinated with each other in this case.
[0151] In an alternative embodiment, the liquid-carrying conduit 12 can be provided essentially along the entire active length of the inductor 10 as in FIG. 8 , in order to ensure more extensive distribution of the injected liquid.
[0152] The approach explained with reference to FIG. 9 is advantageous in that the required water processing is less resource-intensive than it is for the steam-based method, since the injection water does not have to be vaporized above ground.
[0153] Water that has been heated via continuous heat exchangers (not shown in FIG. 9 ) can also be used for the injection, in order to avoid unwanted cooling of the deposit and hence a drop in pressure or an increase in viscosity in the deposit.
[0154] It is also advantageous that the entity for temperature maintenance and therefore also for pressure management in the reservoir is easy to adjust.
[0155] Further advantages of the above described combination of the medium-frequency inductive method for heating the reservoir with the simplified method for water processing and water re-injection are considered to include, for example, the fact that process engineering overheads required to establish the overall water processing plant are reduced, in particular for the feed water processing, and that waste water is avoided or reduced.
[0156] In comparison with the generation of steam for injection into the reservoir, a clear energy saving is achieved as a result of avoiding the heat losses that are produced during the steam generation.
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An apparatus is provided for delivering a substance containing hydrocarbons from a reservoir. The reservoir can be subjected to thermal energy in order to reduce the viscosity of the substance. The apparatus includes at least one conductor loop for inductively applying current for electric/electromagnetic heating of the reservoir, and a pressurization device for injecting a liquid into the reservoir in liquid form. A preparation entity extracts the liquid that is to be injected from a reservoir liquid that is taken from the reservoir or from a medium that is taken from the reservoir.
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RELATED APPLICATIONS
This application is partly related to subject matter disclosed copending patent application Ser. No. 583,773, filed of even date.
BACKGROUND OF THE INVENTION
As related in the copending application, it is often necessary to retrieve a fish from a well during drilling, completion, or workover activities. Many items are equipped with a standard API fishing neck, but this is not always the case. The present invention is an apparatus which retrieves those items which must be hollow, such as tubing. The present invention particularly finds application in retrieval of hollow members. It works with the apparatus in the related disclosure to provide a tool which enables retrieval of practically all types and shapes of fishes.
The present disclosure is to be contrasted with the related application. The present invention utilizes a similar cam and cam follower mechanism. It is able to be latched to on the interior of a fish and released readily. Connection with the fish and release therefrom are easily achieved by repetitive jarring motions which are accomplished without breaking any parts such as shear disks, shear pins, and so on. Engagement and disengagement of the tool with the fish is achieved with a minimum of effort.
The present invention is particularly able to be run on a wireline or can be connected at the bottom of a tubing string to enable fluid flow through the tubing string to wash through the tool to wash away sand or other debris which may block its use. When it is run on a wireline, the wireline can be readily manipulated to provide consecutive jarring motions through the use of mechanical or oil jars which impart the necessary jarring motion to the tool to cause it to engage or disengage. Engagement is achieved when a serrated set of fingers are expanded interiorally of a tubular member and brought into gripping contact with the inner surface, thereby enabling the tool to raise the fish. If the fish is stuck, a subsequent jarring action of the tool causes release and enables the tool to be retrieved. When this occurs, a heavier gauge cable and tool can be subsequently run and exposed to greater stress and strain.
SUMMARY OF THE INVENTION
The present invention is a spear-type retrieval tool for engaging a fish in a well. It incorporates an elongate body with a tubular sleeve thereabout. The sleeve is slidably mounted on he body and is urged downwardly by a compressed coil spring. Axial movement of the sleeve is controlled by a cam and cam follower mechanism. They preferably comprise a set of internally protruding pins carried on the sleeve which engage a shaped groove cut in the exterior of a tubular member. The tubular member is a portion of the elongate body captured between a pair of thrust washers so it is free to rotate. It moves relatively axially controlled by the cam followers which are the protruding pins. The lower end of the tubular body terminates in an elongate tapered plug which is positioned opposite to the tips of the several collet fingers appended to the lower end of the tubular sleeve. The collet fingers are equipped with teeth or serrations on the exterior surface. Since they are positioned opposite the tapered plug, they are forced outwardly against the fish to take a bite and retrieve the fish. The tubular sleeve has a protruding shoulder on the exterior which catches against the top end of the fish, thereby securing the tool at a position where a jarring operation will rotate the tubular member supporting the groove and thereby enable the cam and cam follower to relatively move the body and tubular member, shifting the lower end of the collet fingers relative to the tapered plug. This achieves the engaging and disengaging operation.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a lengthwise sectional view along a diameter of the fishing spear of the present invention showing details of construction including the cam and cam follower mechanism which enables it to shift axially in retrieving a fish;
FIG. 2 discloses the groove arrangement on the exterior of the tubular member showing the exterior surface in planar presentation and illustrating the path followed by a protruding pin captured in the groove; and,
FIG. 3 is a view through the lower portions of the tool showing the collet fingers engaged with the fish.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In FIG. 1, a fishing spear 10 incorporates the advantages of the present invention. A tubular body 11 has a threaded female connection 12 at the upper end to enable it to be connected to a rope socket or to a tubing string. A rope socket is threaded at 12 to enable it to be run on a wireline. Wireline operation is normally more convenient, and this is the customary or intended use of the tool. However, when the spear 10 is to be run in a well where washing action is required to remove sand and debris, a tubing string is connected to the tool to enable washing fluid to be pumped through the tubing string and through the spear 10 to achieve washing or jetting action. The body 11 has an axial passage 13 to receive a washing fluid therethrough. It extends all the way to the bottom of the tool, as will be described.
The body 11 has a downwardly facing shoulder 14 which receives a coil spring 15 therein. For large spring forces, a stack of Bellville springs may be used. The coil spring 15 creates an axial force bearing on a slidably mounted tubular member 16. It is forced downwardly under movement controlled by a cam and cam follower mechanism to be described. The coil spring 15 bears against the upper shoulder 17 of the tubular body 16. A downwardly facing shoulder 18 cooperates with an upwardly facing shoulder 19 on the slidable sleeve 16 to limit upward travel of the sleeve 16. The shoulder 18 is formed on the exterior of a relatively narrow neck 20 which extends below the body 11. The neck 20 is fairly long and extends into the sleeve 16 as illustrated.
The elongate body is continued by threading a lower hollow member 23 into the lower end of the neck 20. A threaded connection is achieved at 24. The body 23 has the same external diameter as the neck 20 below the shoulder 18. It provides a continuation of the axial passage 13. The tubular body 23 has a reduced diameter at its upper end to enable it to receive a thrust washer 26 against a shoulder. The thrust washer is adjacent to a cam body 27. The cam body is just below a similar thrust washer 28. The components 26, 27 and 28 are telescoped on the tubular body 23 which is threaded to the threads 24. This captures the components on the relatively small neck appended to the upper end of the tubular body 23. The thrust washers and cam body are sized to have an external diameter which is equal to that of the neck 20 below the shoulder 18 and equal to the diameter of the tubular body 23. The thrust washers 26 and 28 capture the cam body 27 but do not hold it so snugly that it is prevented from rotating. It rotates on axial movement under control determined by a set of internally protruding pins 30 in the sleeve 16. The pins 30 have a length enabling them to extend into a groove cut in the exterior of the cam body 27. The shape of the groove is shown in FIG. 2.
The tubular member 23 has an internally threaded countersunk opening 32 at its lower end for receiving an elongate tapered plug 33. The passage which extends through the tubular body 23 also extends through the plug 33 and to an outlet 34 at the lower end. The plug 33 has an external surface 36 which is elongate and tapered. The surface 36 works with a set of collet fingers as will be described.
The tubular sleeve 16 is threadedly connected to a ring 38. The ring 38 supports a set of collet fingers 40. The collet fingers are defined by elongate grooves cut in the stock which extend upward to the ring 38. The grooves control the spacing of the fingers. Typically four fingers will suffice, although the numbers can be varied. The collet fingers are flexible to deflect outwardly under urging of the tapered plug 33. The collet fingers all terminate in a set of external serrations 41. The serrations take a bite in the fish shown in dotted line at 44. When they are forced against the fish, they grip it sufficiently to enable its retrieval. The serrations 41 face upwardly in that they define a sharp shoulder which faces upwardly of the fish.
The ring 38 threads to the tubular member 16 as previously noted. A protruding washer 45 is captured at the threaded connection. It extends outwardly by a distance sufficient to enable it to contact or find the top end of a fish. The protruding washer rests or supports the tool against the fish so that a portion of the tool is held stationary relative to the fish while another portion of the tool reciprocates in setting the tool to the engaged position. An O-ring 46 provides a seal against the intrusion of well fluids in the relatively small space between the tubular sleeve 15 and the elongate body.
FIG. 3 should be contrasted with FIG. 1. FIG. 1 shows the apparatus in the disengaged position relative to the fish 44. In FIG. 3, the tapered plug 33 has been pulled upwardly relatively to the collet fingers 40. This axial movement of the plug forces the tapered plug 43 against the back side of the serrated collet fingers 40. The lower tips of the fingers 40 have a conforming back surface 48 which slides along the face of the tapered plug 33. The relative axial movement forces the tips of the collet fingers radially outwardly. This forces the serrations 41 into firm contact with the fish, thereby engaging the fish for retrieval. Retrieval is achieved by axially pulling on the spear 10 to retrieve the fish. The illustrated positions of FIGS. 3 and 1 disclose the engaged and disengaged positions. For a better understanding of its operation, the cam and cam follower mechanism which includes the pin 30 and cam body 27 will be described. The referenced disclosure utilizes the same cam and cam body arrangement inverted in comparison with the present disclosure. The cam and cam body mechanism provides controlled axial movement between two positions which differ axially and enable the tool to operate from an engaged to disengaged to engaged position repetitively.
In FIG. 2, a groove 50 extends to the lower end of the cam body 27. The groove 50 enables the cam body to be assembled and to capture the protruding pin 30 therein. At the time of assembly the thrust washer 26 is placed on the lower tubular body 23. The cam body 27 is dropped into the tubular sleeve 16 until it lands on the pins 30. It is rotated until the pins 30 find the grooves 50. The groove 50 is duplicated at 180° points about the body 27 so that it matches the position of the pins. A different number of pins could be used, but this is not necessary. The groove 50 is slightly larger in width than the diameter of the pin 30. This enables the pin 30 to move without binding. When received in he groove 50, the pin 30 defines a first position. The cam body and groove is so constructed to controllably move the pin between first and second stable positions. It is not necessary to achieve any other stable position. Movement of only one pin will be described although two pins are normally used. The preferred embodiment incorporates a pair of pins which are diametrically opposite one another as shown in FIG. 1. Inasmuch as each pin cooperates with a portion of the grooves on the exterior of the body 27 which is identically contoured, it is believed unnecessary to describe duplicate motions.
The groove 50 extends toward a facing wall 52 of an angled groove portion. It is opposite the groove and extends angularly relative to the groove 50 and causes the pin 30 to deflect along the illustrated path. The wall 52 and a wall 53 intersect in a curved groove shoulder 54. The shoulder 54 is curved and has a radius which fairly matches and exceeds that of the pin 30. This avoids point contact when the pin 30 moves into the intersection of the shoulders 52 and 53. The curved intersection 54 is located opposite a facing shoulder 55 which is set at an angle to intercept and deflect the moving pin. The shoulder 55 intersects a shoulder 56 at a curved intersection 57. The radius of curvature at 57 is about the same as that at 54.
The arrows 60 and 61 identify relative upward movement of the pin 30. It is one motion which is redirected by the facing shoulder 52. The pin 30 moves along the path indicated by the arrows 60 and 61 when a jarring motion is applied to the spear 10°. The path of the pin 30 continues along the direction indicated by the arrows 62 and 63. This is achieved in one motion but the pin 30 is deflected by the shoulder 55. The motion continues to the curved shoulder 57 where the pin 30 is captured in the second position. The reversal of sliding motion of the sleeve 16 relative to the body is achieved by contact of the shoulders 18 and 19 and not by rebound of the pin 30 in the groove.
The pin remains stable at the second position and remains there until the next operation of the tool. In traveling from the first to the second position, relative axial shifting of the cam body 27 is imparted to the tapered plug 33. This relative motion moves the tapered plug from the engaged to the disengaged position. This deflects the fingers outwardly or inwardly as the case may be to bring them into engagement or disengagement with the fish. Upward movement of the tubular member 16 is limited by the facing shoulders 18 and 19. They preferably engage just prior to travel of the pin 30 into the curved corner 54. This prevents the pin from receiving substantial shearing impact. On the rebound which occurs at the urging of the spring 15, the pin moves away from the curved corner 54 along the arrow 62.
The dotted line position of FIG. 2 represents the second position of the pin. It can rest there indefinitely. However, on subsequent operation, a jarring motion applied to the spear 10 carries the pin 30 from the curved corner 57 toward the oppositely facing shoulder 66. The shoulder 66 intersects the shoulder 67 at a curved or radiused corner 68. The corner 68 diverts and guides the pin in its travel and deflects it toward a facing shoulder 70. The facing shoulder 70 guides the pin back toward the lengthwise groove 50. In the groove 50 the pin is returned to the first position. Movement in the upward direction is achieved by a downward jar applied to the spear 10 while movement in the downward direction is achieved by rebound of the coil spring.
This describes movement of the pin in the cam body between the two positions. This movement enables the sphere to operate successively between engaged and disengaged positions repetitively, without limit.
It should be understood how the cam and cam follower mechanism control upward and downward movement of the relatively slidable parts of the present invention. Many details can be varied. The size and shape of the collet fingers and tapered plug are subject to variation depending on the circumstances of different fishing jobs. Other design details can be varied. The scope of the present invention is determined by the claims which follow.
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A releasable spear adapted to be run on a wireline or a tubing string, as desired, incorporates an elongate body and an external slidable sleeve. The sleeve is forced downwardly by a compressed spring at the top end of the sleeve. The sleeve supports a pair of internal projecting lugs which are received in an external groove formed in a tubular member. The lugs and groove function as a cam and cam follower mechanism controlling upward and downward movement. The body terminates in an elongate tapered plug. The lower end of the sleeve incorporates a set of collet fingers which have external upwardly facing serrations to lock on the interior of a fish. The external sleeve incorporates a protruding shoulder which catches the upper end of the fish. The cam and cam follower mechanism controls axial movement of the elongate tapered plug to force the collet fingers outwardly to engage, or cause them to deflect inwardly to disengage a fish.
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FIELD OF THE INVENTION
[0001] The present invention relates to semiconductor manufacturing of thin substrates or wafers and, more particularly, to the transfer and loading of semiconductor wafers, glass plates and the like into and out of processing chambers.
BACKGROUND OF THE INVENTION
[0002] Semiconductor manufacturing generally requires that a number of different processes be applied to a substrate such as a wafer. Typically, each process is applied to a wafer in a different chamber dedicated to a respective process. Thus the manufacturing process involves not only a sequence of processes carried out in the respective chambers, but also transporting wafers among the processing chambers, and loading and unloading wafers into and out of the processing chambers. Most semiconductor processing is carried out in chambers configured to process one wafer at a time, in a very high vacuum capable environment. Thus, a process to be performed in a particular chamber cannot be carried out while wafers are being loaded into or removed from the processing chamber. Consequently, reducing the time required to load and unload wafers into and out of processing chambers is a significant factor in maximizing manufacturing throughput.
[0003] It is therefore desirable to provide for rapid and reliable transfer of wafers to and from processing chambers. It is also desirable that chamber components which aid in the transfer of wafers be simple and inexpensive to manufacture.
SUMMARY OF THE INVENTION
[0004] According to a first aspect of the invention, a lift pin/actuating assembly includes a lift pin and an actuating mechanism having an actuator configured to generate movement by the lift pin along a first axis, and a translation mechanism coupled to the actuator and configured to translate movement of the actuator along the first axis into movement by the lift pin along a second axis.
[0005] According to a second aspect of the invention, a method of operating a substrate lift pin includes applying vertical actuation to the pin, moving the pin vertically a first distance, contacting a vertical motion stop after moving the first distance, and translating further vertical actuation into horizontal movement of the pin.
[0006] According to a third aspect of the invention, a lift pin/actuating assembly for a semiconductor processing chamber includes a lift pin adapted to hold a semiconductor substrate in the processing chamber. Also included in the lift pin/actuating assembly are a base on which the lift pin is mounted, a first mechanism adapted to raise and lower the base, and a second mechanism adapted to convert vertical motion of the base into pivoting motion of the lift pin.
[0007] According to a fourth aspect of the invention, a method of operating a semiconductor processing chamber includes providing a lift pin, mounting the lift pin so that it extends upwardly into the processing chamber, lowering a base on which the lift pin is mounted, and converting the lowering motion of the base into pivoting motion of the lift pin.
[0008] Other objects, features and advantages of the present invention will become more fully apparent from the following detailed description of the preferred embodiments, the appended claims and the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] [0009]FIG. 1 is a somewhat schematic cross-sectional view of a processing chamber provided in accordance with an aspect of the invention, showing a lift pin in storage position;
[0010] [0010]FIG. 2 is a view similar to FIG. 1, showing the lift pin in a retracted position; and
[0011] FIGS. 3 ( a )- 3 ( l ) are partial cross-sectional views of the processing chamber of FIGS. 1 and 2, showing an exemplary sequence of steps for a substrate exchange procedure.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0012] An embodiment of the invention includes a lift pin/actuating assembly that employs a single actuator and a translation mechanism configured to translate actuation along a first axis into movement along a second axis (“movement along an axis” should be understood to include linear motion in the direction of the axis, or pivotal motion about the axis.) The actuating assembly is configured to allow actuation along the first axis to result in a predetermined range of lift pin movement along the first axis. Beyond the predetermined range of lift pin movement, further actuation along the first axis is translated into movement along the second axis. The translation mechanism may include a motion stop which defines the predetermined range of lift pin movement and a motion translator (e.g., a lever or an appropriately configured link such as a four bar link, etc.).
[0013] An aspect of the invention that employs a vertical motion actuator, a vertical motion stop, and a lever configured to translate vertical linear motion into horizontal pivoting motion is shown and described with reference to FIGS. 1 - 3 ( l ).
[0014] [0014]FIG. 1 is a schematic cross-sectional view of a semiconductor processing chamber 10 provided in accordance with an aspect of the invention. The processing chamber 10 includes an enclosure 12 defined by side wall 14 , chamber floor 16 and chamber top 18 .
[0015] A heated pedestal 20 is mounted in the processing chamber 10 on a shaft 22 . A lift mechanism 24 is associated with the shaft 22 to selectively raise and lower the pedestal 20 . The pedestal 20 is provided to support a wafer in the chamber 10 during processing.
[0016] Conventional lift pins (of which only one pin 26 is shown) are provided to selectively lift a wafer from the pedestal 20 or to deposit a wafer on pedestal 20 . The lift pins are raised and lowered via a lift plate 28 and a lift mechanism 30 .
[0017] Reference numeral 32 represents a robot blade that has entered the processing chamber 10 via a slit valve 34 while carrying a wafer 36 . A so-called “showerhead” 38 is suspended from the chamber top 18 and allows process gas to flow toward the pedestal 20 during processing.
[0018] In accordance with an aspect of the invention, a plurality of lift pins, and associated actuating mechanisms, are provided to define a wafer storage position within the enclosure 12 . For clarity, only one lift pin 40 and its associated actuating mechanism 42 are shown. Note in the exemplary embodiment shown, the actuating mechanism 42 is positioned below the floor 16 of the processing chamber 10 , and the lift pin 40 extends into the enclosure 12 via an opening 43 in the floor 16 . The lift pin 40 has a horizontally extending upper section 44 , on which a wafer is supported during storage. The lift pin 40 may be mounted directly to a lever 48 or may be held in a holder 46 which in turn is mounted on the lever 48 . The lift pin 40 may be fixedly coupled to the lever 48 such that the angle therebetween remains fixed. The lever 48 is mounted by means of a pivot 50 on a moveable base 52 . A lift mechanism or actuator 54 is associated with the base 52 to selectively raise and lower the base 52 .
[0019] A spring 56 is connected between the base 52 and a free end 58 of the lever 48 . The spring 56 biases the free end 58 of the lever 48 in a downward direction (counter-clockwise about the pivot 50 in FIG. 1). A step 60 on the base 52 defines a horizontal position of the lever 48 by limiting the downward motion of the lever 48 relative to the base 52 . A stop 62 is suspended from the chamber floor 16 and is positioned under the free end 58 of the lever 48 . A bellows 64 accommodates translational and angular motion of the lift pin 40 and its holder 46 while preventing particles from the external environment from entering the enclosure 12 via the opening 43 .
[0020] Those who are skilled in the art will appreciate that a controller (not shown) is associated with processing chamber 10 to control operation of lift mechanisms 24 , 30 , 54 , slit valve 34 , and other components of processing chamber 10 which are not shown.
[0021] The inventive lift pin/actuating assembly is shown in its storage position in FIG. 1. Because of the relative positioning of the base 52 and the stop 62 , stop 62 does not come into play when the base is positioned as shown in FIG. 1, and the position of the lever 48 , as biased downwardly by the spring 56 , is determined by the step 60 of the base 52 . Lever 48 is in substantially a horizontal orientation, and lift pin 40 is in substantially a vertical orientation with the upper section 44 of lift pin 40 obstructing a path of travel of pedestal 20 .
[0022] Lift pin 40 is shown in its retracted position in FIG. 2. To move the lift pin 40 from its storage position (FIG. 1) to its retracted position (FIG. 2) the base 52 is moved downwardly from the position shown in FIG. 1. The movement of base 52 in the downward direction is actuated by lifting mechanism 54 . As the base 52 is moved downwardly, the stop 62 comes in contact with the free end 58 of the lever 48 , pushing the free end 58 of the lever 48 upwardly relative to the base 52 , against the biasing force of the spring 56 . The lever 48 , in response to contact with stop 62 , thus pivots on pivot 50 , causing holder 46 and lift pin 40 to be inclined or tilted from the vertical, thereby bringing lift pin 40 to its retracted position shown in FIG. 2. In its retracted position lift pin 40 does not obstruct the path of travel of pedestal 20 .
[0023] It will be recognized from FIGS. 1 and 2 that base 52 may be considered to have two ranges of movement. In a first range of movement at and above its position in FIG. 1, movement of base 52 raises or lowers lift pin 40 without pivoting lift pin 40 (as the lever 58 does not contact the stop 62 ). In a second range of movement between its respective positions in FIGS. 1 and 2, movement of base 52 results in pivoting of lift pin 40 (as the lever 58 contacts the stop 62 and pivots in response to contact therewith).
[0024] With the lift pin actuating mechanism 42 shown in FIGS. 1 and 2, a single lift mechanism or actuator 54 is employed both to translate the lift pin 40 in a vertical direction and to impart angular motion to the lift pin 40 (by means of the interaction between the lever 48 and the stop 62 ). That is, the single lift mechanism 54 both raises and lowers lift pin 40 and pivots lift pin 40 between the storage position and the retracted position. Consequently, the inventive actuating mechanism 42 provides a relatively simple and cost effective arrangement for both raising and pivoting the lift pin 40 .
[0025] FIGS. 3 ( a )- 3 ( l ) illustrate steps performed during an exemplary wafer exchange operation with respect to the processing chamber 10 .
[0026] [0026]FIG. 3( a ) shows a condition that is in effect at a time when processing of wafer 36 is complete. It will be observed that wafer 36 is supported on the pedestal 20 in a processing position near the top of the processing chamber. The lift pin 40 is in its retracted (non-storage) position so that it does not obstruct the path of travel of the pedestal 20 .
[0027] After the condition of FIG. 3( a ), the pedestal 20 is lowered and the lift pin 26 lifts the wafer 36 from the pedestal 20 , to produce the position shown in FIG. 3( b ). The pedestal 20 is now in a loading position.
[0028] Next, the lift pin 40 is actuated, i.e. moved from its retracted position (FIG. 3( b ), FIG. 2) to its storage position (FIG. 3( c ), FIG. 1). The lift pin 40 is no longer inclined, but rather is upright or vertical and hence positioned to support the wafer 36 on the upper section 44 of the lift pin 40 . From the foregoing discussion of FIGS. 1 and 2, it will be recognized that the pivoting of the lift pin 40 from its retracted position to its storage position is accomplished by raising the base 52 so as to free the lever 48 from contact with the stop 62 , thereby leaving lever 48 free to pivot downwardly in response to the biasing force of spring 56 .
[0029] Next, the lift pin 40 is raised (by further raising the base 52 ) so that the lift pin 40 lifts the wafer 36 from the lift pin 26 . The resulting position is shown in FIG. 3( d ). In the condition shown in FIG. 3( d ) the wafer 36 is held in a storage position by the upper section 44 of the lift pin 40 .
[0030] At the next step, robot blade 32 enters the chamber 10 carrying a new wafer 36 ′ which is to be processed in the chamber. The resulting condition is shown in FIG. 3( e ). The lift pin 26 is then raised to lift the wafer 36 ′ from the robot blade 32 (FIG. 3( f )). The robot blade 32 then retracts from the processing chamber 10 , to result in the condition shown in FIG. 3( g ).
[0031] At the next step of the exchange operation, lift pin 26 is lowered to place the new wafer 36 ′ on the pedestal 20 , as shown in FIG. 3( h ). The robot blade 32 then reenters the processing chamber 10 , this time without a wafer being carried on the robot blade 32 . The resulting condition is shown in FIG. 3( i ). Lift pin 40 , which supports the processed wafer 36 , is then lowered (by lowering the base 52 ) to place the wafer 36 on the robot blade 32 (FIG. 3( j )). The robot blade 32 is then retracted from the processing chamber 10 , carrying the processed wafer 36 out of the chamber 10 . The exchange of wafers is now complete, resulting in the condition shown in FIG. 3( k ). Lift pin 40 is then moved from its storage position to its retracted position (FIG. 3( l )), by further lowering the base 52 to cause stop 62 to contact and pivot lever 48 (and the lift pin 40 fixedly coupled thereto), so that the path of travel of the pedestal 20 is no longer obstructed by the lift pin 40 . Accordingly, the pedestal 20 supporting the wafer 36 ′ may be raised to the processing position, which was initially shown in FIG. 3( a ).
[0032] The foregoing description discloses only a preferred embodiment of the invention; modifications of the above disclosed apparatus and method which fall within the scope of the invention will be readily apparent to those of ordinary skill in the art. For example, the invention has been illustrated in the context of a chemical vapor deposition (CVD) chamber. The invention may also be applied in a physical vapor deposition (PVD) chamber, an etching chamber, a photolithography chamber, a loadlock chamber, a degassing chamber, a heating chamber, a cooling chamber or at any location where substrates are exchanged. The invention may also be employed in connection with substrates other than semiconductor wafers (e.g., glass plates and the like).
[0033] It will be understood that the embodiment shown in FIGS. 1 - 3 ( l ) is merely exemplary and that the configuration of the lift pin/actuating assembly may vary and still function in accordance with the invention. For instance, a horizontal actuator may move the lift pin to the retracted position, contact a motion stop and translate further horizontal actuation into vertical motion. Further the specific operation of the assembly may change and still function in accordance with the invention. For example, the position of the stop and the motion translator may be reversed such that the motion translator is raised to contact the stop, rather than lowered to contact the stop, etc.
[0034] Accordingly, while the present invention has been disclosed in connection with the preferred embodiments thereof, it should be understood that other embodiments may fall within the spirit and scope of the invention, as defined by the following claims.
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A set of lift pins defines a storage location for a substrate in a substrate processing chamber. Each lift pin has an actuating mechanism including a translating mechanism that translates vertical actuation into horizontal motion. The actuating mechanism may include a base, a mechanism adapted to raise and lower the base, and a lever pivotally mounted on the base. The lift pin may be fixedly mounted on the lever. A stop may be adjacent the base and adapted to engage the lever to pivot the lever as the base is lowered.
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FIELD OF THE INVENTION
This invention relates to beverage mugs, and more particularly to a domed beverage mug having insulative properties for maintaining the temperature of the liquid contained therein.
BACKGROUND OF THE INVENTION
A heightened awareness of health has recently led people to demand better sanitary conditions for food and beverage than has heretofore been accepted. For example, insects and particulate matter with their inherent potential for carrying especially virulent, transmitted diseases are unwelcomed intrusions into conventional drinking glasses and cups. Today's public increasingly does not tolerate unclean conditions that were once commonplace.
Partially in response to this demand, beverage mugs and lidded beer steins are becoming popular again with the drinking public. These vessels hold large quantities of liquid making them ideally suited for picnics and parties at pools and backyards.
Unfortunately, the very fact that such beverage mugs and beer steins have a greater storage capacity causes a problem: liquid contained in them over a significant length of time tends to reach undesirable, ambient temperature, wherein cold items become warmer and hot items become cooler.
The present invention is a beverage mug that has many improved features, including a domed lid that traverses a wide rotative arc in excess of ninety degrees of rotation between the closed mouth position and the open position.
This wide angle of arc provides the advantage of keeping the lid out of the way during drinking, such that it will not interfere with the drinker's face.
Another improvement of this invention includes an insulative design that maintains the liquid at its proper temperature (hot or cold). The mug includes walls made from thermally insulative materials such as polyethylene and polystyrene. The walls of the mug can also comprise an internal hollow cavity to retard heat transfer through the walls. The internal cavity may contain air, styrene foam, urethane foam, or can be evacuated to provide a thermos effect.
The vessel of the beverage mug has a frustro-conical shape to provide stability against tipping over.
A thumb actuator in the form of an elliptical ball allows for ease of lid movement.
SUMMARY OF THE INVENTION
The invention pertains to a thermally insulated beverage mug for maintaining beverage temperatures. The mug comprises a frustro-conical hollow vessel for receiving and dispensing a beverage through its mouth portion.
A handle is disposed on the side of the vessel and has a horizontal handle arm in its top portion. This horizontal handle arm allows for a hinge mechanism to be strapped on top of the handle.
A domed, articulated lid is disposed on top of said mouth portion of the vessel in a first closed mouth position. The lid is rotatively movable from the first, closed mouth position to a second open mouth position through a rotative arc in excess of 90 degrees, and preferably about 110 degrees.
A right angled hinge connects the domed lid to the horizontal handle arm. The hinge mechanism comprises a vertical hinge arm strapped to the handle and a horizontal hinge arm that is riveted to the lid. The horizontal hinge arm is rotatively pinned to the vertical hinge arm at a hinge fulcrum.
The horizontal hinge arm has a strap abutment that mates and engages with a limit abutment on the vertical hinge arm. The stop and limit abutments have an open angle in excess of 90 degrees from the first, closed mouth position of the lid.
A thumb actuator disposed in a vertical position directly over the vertical hinge arm is integrally attached to the horizontal hinge arm. The thumb actuator has an elliptical ball shape and causes the lid to move through its rotative arc from the first to the second position.
The vessel of the mug can have a hollow space between its inner and outer walls for retarding thermal conductivity through the vessel walls. The hollow space may contain air (a good thermal insulator), styrene foam or urethane foam. The hollow space can be evacuated to provide a thermos effect.
It is an object of this invention to provide an improved beverage mug.
It is another object of the invention to provide an insulated mug for maintaining beverage temperature.
It is another object of the invention to provide a thermal beverage mug having attractively aesthetic characteristics.
It is still another object of the present invention to provide a means for precluding the intrusion of foreign matter into the contained beverage.
It is a further object of this invention to provide a mug with a domed lid that has a wide angle of rotative arc, so that the lid will not interfere with the face of the drinker during the drinking of the beverage.
BRIEF DESCRIPTION OF THE DRAWINGS
A complete understanding of the present invention may be obtained by reference to the accompanying drawings, when taken in conjunction with the detailed description thereof and in which:
FIG. 1 is a perspective view of the beverage mug of the invention, shown with its domed lid in a closed position;
FIG. 2 is a partial perspective view of the beverage mug of FIG. 1, illustrating the domed lid in an open position; and
FIG. 3 is a partial, enlarged, expanded view of the hinge pin section of the hinge mechanism of the beverage mug of FIGS. 1 and 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Generally speaking, the invention features an insulated beverage mug having a domed lid with a wide angle of rotation to prevent interference with the face of the drinker during the drinking of the beverage.
For purposes a brevity, like components will bear the same designation throughout the figures.
Referring now to FIG. 1, the drinking mug 10 of this invention is shown. The mug 10 comprises a frustro-conical container 9 having an outer wall 11 and an inner wall 12 that defines an inner cavity 13 for receiving and dispensing liquids.
A handle 14 is disposed on the side of vessel 9 and is integrally formed therewith.
The vessel 9 and handle 14 can be molded from a solid plastic or a plastic having a hollow space 15 therein.
The hollow space 15 can be filled with air, which is a good thermal insulator, or with a foam material, such as a styrene or urethane foam.
The hollow space 15 can also be evacuated to provide a thermos effect.
The mouth 16 (FIG. 2) of vessel 9 is covered in a closed mouth position (FIG. 1) with a domed lid 17, which is rotated (arrow 18) out of the way in the open mouth position, shown in FIG. 2.
The lid 17 is rotated by means of a hinge mechanism 19.
The hinge mechanism 19 includes a vertical arm 20 that is strapped to a horizontal arm 21 of handle 14 via cylindrical strap member 22.
The vertical hinge arm 20 rotatively supports a horizontal hinge arm 23 attached to dome lid 17 via rivets 24. It should be understood that hinge arm 23 may also be attached to lid 17 by means of screws or any other suitable mechanical or space age adhesive means.
The horizontal hinge arm 23 rotates about the hinge fulcrum 25 provided by hinge pin 26, shown in more detail in FIG. 3.
The horizontal hinge arm 23 terminates in a stop abutment 27 that engages with a limit abutment 28 disposed at the top of vertical hinge arm 20. These abutments 27, 28 limit the rotative arc of travel of lid 17, which is approximately 110 degrees from the closed mouth position of FIG. 1.
It should be understood that other mechanisms known in the art can be used to attach hinge mechanism 19 to mug 10. Such mechanisms may include, but are not necessarily limited to, metal straps, blocks and pins configurations.
The lid 17 is actuated for rotation (arrow 18) by means of a thumb knob 30 that has an elliptical ball shape.
The lid 17 is returned to its closed position, as shown in FIG. 1, by means of upward pressure on elliptical thumb knob 30.
The container 9 can be molded from thermal plastics, such as polyethylene and polystyrene.
A circumferential rim or lip 35 can be molded into wall 11 to support the mug 10, making it less unwieldy during use. The lip 35 is approximately 1/4" wide, 1/16" thick and is rounded for the user's comfort. The preferred position of the lip 35 is approximately 3/4" from the mouth 16.
Having thus described the invention, what is desired to be protected by Letters Patents is presented by the subsequently appended claims.
Since other modifications and changes varied to fit particular operating requirements and environments will be apparent to those skilled in the art, the invention is not considered limited to the example chosen for purposes of disclosure, and covers all changes and modifications which do not constitute departures from the true spirit and scope of this invention.
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The invention features a thermally insulated beverage mug having a hollow internal walled section for retarding thermal conductivity between inner and outer vessel walls. The beverage mug also features a hinge mechanism and domed lid for closing the mouth of the vessel when the vessel is not in use.
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CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is a continuation application of U.S. application Ser. No. 14/186,829, filed Feb. 21, 2014, which is a divisional application of U.S. application Ser. No. 13/144,031 (now U.S. Pat. No. 8,697,740), filed Sep. 23, 2011 as a U.S. National Phase application under 35 U.S.C. §371 of PCT/US2010/020460, filed Jan. 8, 2010, which claims priority from U.S. provisional Application Ser. No. 61/204,886, filed Jan. 12, 2009. The present application claims priority to the foregoing applications.
FIELD OF THE INVENTION
The present invention relates to novel polymorphic forms of a compound of formula A. This compound is useful as a pharmaceutically active ingredient for the treatment of type 2 diabetes and related conditions, such as hyperglycemia, obesity, dyslipidemia, and the metabolic syndrome.
BACKGROUND OF THE INVENTION
Type 2 diabetes remains a serious medical problem. There is an ongoing need for new treatments that are more effective and that have fewer side effects. Glucagon receptor antagonists are important upcoming medications for the treatment of type 2 diabetes and the present compound is particularly useful in this regard.
SUMMARY OF THE INVENTION
The present invention relates to polymorphic forms of a compound of formula A:
The compound is also known as N-(4-{(1S)-1-[(R)-(4-chlorophenyl)(7-fluoro-5-methyl-1H-indol-3-yl)methyl]butyl}benzoyl)-β-alanine. Compound A has been disclosed in a published PCT patent application, WO2008/042223 published on Apr. 10, 2008. Polymorphic forms of the compound that are particularly useful in the preparation of pharmaceutical products are described herein.
The invention also relates to pharmaceutical compositions comprising the polymorphic forms described herein, methods for the preparation thereof and the like
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described in connection with the drawings appended hereto, in which:
FIG. 1 is the X-ray powder diffraction (XRPD) pattern for the free acid hydrate polymorphic Form I of Compound A;
FIG. 2 is the solid-state 19 F CPMAS NMR spectrum of the free acid hydrate polymorphic Form I of Compound A;
FIG. 3 is the 13C solid state NMR of the free acid hydrate polymorphic Form I of Compound A;
FIG. 4 is the X-ray powder diffraction (XRPD) pattern of anhydrous free acid polymorphic Form I of Compound A;
FIG. 5 is the 19F solid state NMR of anhydrous free acid polymorphic Form I of Compound A;
FIG. 6 is the X-ray diffraction pattern of the crystalline anhydrate Form II of Compound A;
FIG. 7 is the Thermogravimetric analysis curve of the crystalline anhydrate From II of Compound A;
FIG. 8 is the Differential Scanning calorimetry curve of the crystalline anhydrate Form II of Compound A;
FIG. 9 is the Solid State C-13 CPMAS NMR spectrum for the crystalline anhydrate Form II of Compound A;
FIG. 10 is the Fluorine-19 Single Pulse Excitation MAS spectrum of Anhydrate II of Compound A.
FIG. 11 is the X-ray Powder Diffraction pattern of the crystalline anhydrate Form III of Compound A;
FIG. 12 is the Thermogravimetric analysis curve of the crystalline anhydrate Form III of Compound A;
FIG. 13 is the Differential Scanning calorimetry curve of the crystalline anhydrate Form III of Compound A;
FIG. 14 is the Solid State C-13 CPMAS NMR spectrum for the crystalline anhydrate Form III of Compound A;
FIG. 15 is the Fluorine-19 Single Pulse Excitation MAS spectrum of crystalline anhydrate Form III of Compound A, and
FIG. 16 is an X Ray Powder Diffraction pattern for comparison purposes of Compound A containing a mixture of amorphous product and polymorphs.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a process for the preparation of crystalline N-(4-{(1S)-1-[(R)-(4-chlorophenyl)(7-fluoro-5-methyl-1H-indol-3-yl)methyl]butyl}benzoyl)-β-alanine of structural formula A:
and specifically polymorphic forms thereof, including solvates.
Crystal forms are convenient for the preparation and isolation of compound A with an upgrade in purity, and represent a convenient scalable way to produce high purity compound A. Crystalline forms were identified including the crystalline free base of Compound A as an alcohol solvate and various crystalline salt forms of Compound A are included as well. These crystalline salts of compound A are novel and have improved physiochemical properties, such as purity, stability and ease of formulation that render them particularly suitable for the manufacture of pharmaceutical dosage forms. Discovery of crystalline forms allowed for the facile purification, isolation, and formulation of compound A.
The abbreviations in the table below have the following meanings:
Me = methyl
Et = ethyl
t-Bu = t-butyl
IPA = isopropyl alcohol
Ac = Acetyl
THF = tetrahydrofuran
DCM = dichloromethane
DIEA = diisopropylethylamine
DMF = dimethylformamide
DPE phos = Bis(2-
diphenylphosphinophenyl)ether
IPAC = isopropylacetate
MTBE = methyl t-butyl ether
BINAP = 2,2′-bis(diphenylphosphino)-
Tol-BINAP = 2,2′-bis(di-p-
1,1′-binaphthyl
tolylphosphino)-1,1′-binaphthyl
One aspect of the invention that is of interest relates to process for synthesizing a compound of formula A:
comprising deprotecting a compound of formula 11a:
wherein P 1 and P 2 represent protecting groups, to produce a compound of formula A.
Another aspect of the invention relates to a process for synthesizing a compound of formula A:
comprising reacting a compound of formula 10a:
wherein P 1 represents a protecting group with a beta alanine ester of the formula
H 2 NCH 2 CH 2 CO 2 P 2
wherein P 2 represents a protecting group, with a peptide coupling agent, to produce a compound of formula 11a:
and deprotecting compound 11a to produce a compound of formula A.
Another aspect of the invention relates to a A process for the synthesis of a compound of formula A:
comprising reacting a compound of the formula 11:
with base to produce a compound of formula A.
Another aspect of the invention relates to a process as described above wherein the base is NaOH.
Another aspect of the invention relates to a process for synthesizing a compound of formula A as shown above.
A compound of formula 10a is reacted with N,N-carbonyldiimidazole (CDI) or another peptide coupling reagent and a beta-alanine ester H 2 NCH 2 CH 2 CO 2 P 2 to produce a compound of formula 11a. P 1 represents a protecting group suitable for protection of the indole nitrogen atom. Representative examples include nosyl, benzyl, tolyl and similar groups, with nosyl being preferred. Suitable protecting groups for the beta alanine ester, P 2 , include small alkyl groups, such as methyl. Thereafter deprotection is undertaken to remove P 1 and P 2 , thus forming a compound of formula A.
A synthetic route for the compound of formula A has been disclosed in WO2008/042223 published on Apr. 10, 2008, hereby incorporated by reference, and is set forth below. In the present invention, seed crystals of compound were generated from lab scale runs and formed before or after chromatographic purification.
Intermediate 1
Racemic 4-[2-(4-chlorophenyl)-1-propylpent-4-en-1-yl]benzoic acid
Step A. tert-Butyl 4-[2-(4-chlorophenyl)-2-oxoethyl]benzoate
A THF solution (200 ml) containing t-butyl 4-bromobenzoate (19.9 g, 77.6 mmol), 4-chloroacetophenone (10 g, 64.7 mmol), Pd 2 dba 3 (1.19 g, 1.29 mmol), BINAP (1.6 g, 2.58 mmol) and NaOtBu (8.7 g, 90.6 mmol) was refluxed under an argon atmosphere for approximately 5 hours. The solution was concentrated and then partitioned between EtOAc and water. The organic phase was washed with water, brine and dried over Na 2 SO 4 . The filtered solution was concentrated and the residue purified by silica gel chromatography using a hexanes/EtOAc gradient to give the title compound. 1 H NMR (500 MHz, CDCl 3 ): δ 7.95 (d, J=8.5 Hz, 2H); 7.93 (d, J=8.7 Hz, 2H); 7.43 (d, J=8.3 Hz, 2H); 7.29 (d, J=8.2 Hz, 2H); 4.30 (s, 2H); 1.58 (s, 9H). LC1 4.01 min. (M-tBu+H)=275
Step B. tert-Butyl 4-[1-(4-chlorobenzoyl)butyl]benzoate
KOtBu (2.55 g, 22.7 mmol) was added to a cooled (ice bath) THF solution (40 ml) containing the intermediate from Step A (5.0 g, 15.15 mmol). After 10 minutes n-propyl iodide (3 ml, 30.3 mmol) was added dropwise. The ice bath was removed and the reaction was monitored by MS-HPLC analysis. The solution was then partitioned (<1 hour) between EtOAc and water. The organic phase was washed with water, brine and dried over Na 2 SO 4 . The filtered solution was concentrated and the residue purified by silica gel chromatography using a hexanes/EtOAc gradient to give the title compound. 1 H NMR (400 MHz, CDCl 3 ): δ 7.90 (d, J=7.8 Hz, 2H); 7.84 (d, J=8.6 Hz, 2H); 7.33 (d, J=8.6 Hz, 2H); 7.31 (d, J=8.3 Hz, 2H); 4.51 (t, J=7.2 Hz, 1H); 2.18-2.08 (m, 1H); 1.84-1.68 (m, 1H); 1.54 (s, 9H); 1.38-1.18 (m, 2H); 0.90 (t, J=7.3 Hz, 3H). LC1 4.43 min. (M-tBu+H)=317
Step C. tert-Butyl 4-{1-[(4-chlorophenyl)(hydroxy)methyl]butyl}benzoate
NaBH 4 (0.5 g, 13.21 mmol) was added in portions to a MeOH solution (40 ml) containing the intermediate from Step B (3.78 g, 10.16 mmol). After stirring for 1 hour the solution was concentrated and the residue partitioned between EtOAc and water. The organic phase was washed with water, brine and dried over Na 2 SO 4 . The filtered solution was concentrated and the residue purified by silica gel chromatography using a hexanes/EtOAc gradient to give the title compound as a >10:1 ratio of diastereomers. 1 H NMR (400 MHz, CDCl 3 ): δ 7.93 (d, J=8.3 Hz, 2H); 7.28 (d, J=8.4 Hz, 2H); 7.23 (d, J=8.4 Hz, 2H); 7.18 (d, J=8.4 Hz, 2H); 4.73 (d, J=7.8 Hz, 1H); 2.89-2.83 (m, 1H); 1.58 (s, 9H); 1.57-1.56 (m, 1H); 1.41-1.33 (m, 1H); 1.09-0.91 (m, 2H); 0.72 (t, J=7.3 Hz, 3H). LC1 4.22 min. (M-tBu-OH+H)=301
Step D. 4-[2-(4-Chlorophenyl)-1-propylpent-4-en-1-yl]benzoic acid
A 1,2-dichloroethane (DCE) (20 ml) solution containing the intermediate from Step C (1.81 g, 4.84 mmol), allyl trimethylsilane (6.2 ml, 38.7 mmol) and boron trifluoride etherate (1.84 ml, 14.5 mmol) was heated at 80° C. for 1.5 hours. The solution was cooled to room temperature and methanol (10 ml) was slowly added. The solution was then concentrated and the residue partitioned between EtOAc and aqueous 1N HCl. The organic phase was washed with water, brine and dried over Na 2 SO 4 . The filtered solution was concentrated to give the title compound (as a ca 3:1 mixture of diastereomers) which was used without further purification. A portion was purified for spectral analysis. Data is for the major diastereomer 1 H NMR (400 MHz, CDCl 3 ): δ 8.07 (d, J=8.3 Hz, 2H); 7.30 (d, J=5.7 Hz, 2H); 7.28 (d, J=5.4 Hz, 2H); 7.08 (d, J=8.3 Hz, 2H); 5.42-5.32 (m, 1H); 4.79-4.66 (m, 2H); 2.83-2.77 (m, 2H); 2.11-2.05 (m, 2H); 1.43-1.29 (m, 2H); 1.00-0.80 (m, 2H); 0.68 (t, J=7.3 Hz, 3H). LC1 4.08 min.
(M+H)=343
NMR experiments (NOE) on advanced compounds (see EXAMPLE 1) derived from INTERMEDIATE 1 established the relative stereochemistry of the minor and major diastereomers of INTERMEDIATE 1 as:
Intermediate 2
4-[(1S,2R)-2-(4-chlorophenyl)-1-propylpent-4-en-1-yl]benzoic acid
Step A. 2-(4-Bromophenyl)-N-[(1R,2R)-2-hydroxy-1-methyl-2-phenylethyl]-N-methylacetamide
Pivaloyl chloride (7.8 ml, 63.3 mmol) was added dropwise to a DCM/THF solution (100 ml/20 ml) containing 4-bromophenylacetic acid (13.59 g, 63.2 mmol). DIEA (11.0 ml, 63.1 mmol) was then added dropwise (exotherm). After stirring at room temperature for 1 hour the solution was poured slowly into a DCM/THF solution (100 ml/20 ml) containing (1R,2R)-(−)-pseudoephedrine (10.5 g, 63.5 mmol) and DIEA (11.0 ml, 63.1 mmol). After stirring overnight at room temperature the solution was concentrated and the residue partitioned between EtOAc and water. The organic phase was washed with aqueous 1N NaOH (2×), aqueous 1N HCl (3×), brine and dried over MgSO 4 . The solution was filtered and concentrated. The oil residue was diluted with 100 ml of toluene and concentrated. The residue was then dissolved in ethyl ether and triturated with hexanes to give the title compound as a white solid. The compound is a 3:1 mixture of amide rotational isomers by proton NMR: 1 H NMR (400 MHz, asterisk denotes minor rotamer, CDCl 3 ): δ 7.42 (d, J=8.3 Hz, 2H); 7.39-7.27 (m, 5H); 7.11*(d, J=8.4 Hz, 2H); 7.04 (d, J=8.3 Hz, 2H); 4.64-4.42 (m, 1H); 4.07-3.94 (m, 1H); 3.82-3.70 (m, 1H); 2.94*(s, 3H); 3.63 (s, 2H); 2.82 (s, 3H); 1.12 (d, J=7.0 Hz, 3H); 0.86*(d, 3H, J=7.0 Hz). LC1 3.23 min. (M+H)=362
Step B. 2-(4-Bromophenyl)-N-[(1R,2R)-2-hydroxy-1-methyl-2-phenylethyl]-N-methylpentanamide
THF (40 ml) was added to dry lithium chloride (8 g, 189 mmol) and diisopropyl amine (9.2 ml, 65.6 mmol) under an argon atmosphere. The suspension was cooled to −78° C. and n-BuLi (1.6M in hexanes, 37.9 ml, 60.6 mmol) was added dropwise. After stirring for 5 minutes the solution was warmed to 0° C. After 5 minutes the solution was cooled to −78° C. and a THF solution (45 ml) containing the intermediate from Step A (10.56 g, 29.15 mmol) was added dropwise. The solution was then stirred at −78° C. for 1 hour and then warmed to 0° C. After 15 minutes n-propyl iodide (4.3 ml, 44.1 mmol) was added dropwise. The solution was stirred at 0° C. for approximately 2 hours. To the reaction mixture was added saturated aqueous NH 4 Cl and EtOAc. The phases were separated and the aqueous phase extracted with EtOAc. The combined organic phases were dried over Na 2 SO 4 , filtered and concentrated. The oil residue was dissolved in ethyl ether/hexanes (4/6) and filtered through a short plug of silica gel. The filtered solution was concentrated to give the title compound. The compound is a 3:1 mixture of amide rotational isomers by proton NMR: 1 H NMR (400 MHz, asterisk denotes minor rotamer, CDCl 3 ): δ 7.42 (d, J=8.4 Hz, 2H); 7.41-7.27 (m, 5H); 7.08 (d, J=8.4 Hz, 2H); 4.56 (q, J=6.7 Hz, 1H); 4.42 (br s 1H); 4.17-4.01*(m, 1H); 3.85*(t, J=7.1 Hz, 1H); 3.55 (t, J=7.2 Hz, 1H); 3.00* (s, 3H); 2.72 (s, 3H); 2.07-1.92 (m, 1H); 1.69-1.58 (m, 1H); 1.33-1.13 (m, 2H); 1.11 (d, J=7.0 Hz, 3H); 0.88 (t, J7.3 Hz, 3H): 0.58* (d, J=6.9 Hz, 3H). LC1 3.76 min. (M+H)=404
Step C. 2-(4-Bromophenyl)-1-(4-chlorophenyl)pentan-1-one
n-Butyl lithium (1.0M in THF, 59 ml, 94.5 mmol) was added dropwise to a −78° C. THF solution (200 ml) containing 4-chloro bromobenzene (22.63 g, 118.2 mmol) under an argon atmosphere. After 10 minutes a THF solution (30 ml) of the intermediate from Step B (15.88 g, 39.4 mmol) was added dropwise. The solution was warmed to 0° C. and stirred for 30 minutes. Diisopropylamine (5.6 ml, 39.4 mmol) was then added dropwise. After 10 minutes the reaction solution was diluted with 200 ml of AcOH/ethyl ether (1/10 by volume). The mixture was partitioned between EtOAc and saturated aqueous NaHCO 3 (foaming). The organic phase was washed with saturated aqueous NaHCO 3 , water, brine and dried over Na 2 SO 4 . The filtered solution was concentrated and the residue purified by silica gel chromatography using hexanes/EtOAc gradient to give the title compound. 1 H NMR (500 MHz, CDCl 3 ): δ 7.86 (d, 2H, J=8.5 Hz); 7.41 (d, 2H, J=8.5 Hz); 7.37 (d, 2H, J=8.5 Hz); 7.15 (d, 2H, J=8.5 Hz); 4.45 (t, J=7.3 Hz, 1H); 2.15-2.07 (m, 1H); 1.81-1.73 (m, 1H); 1.33-1.19 (m, 2H); 0.91 (t, J=7.4 Hz, 3H). LC1 4.25 min. Not ionized
Step D. 2-(4-Bromophenyl)-1-(4-chlorophenyl)pentan-1-ol
Sodium borohydride (917 mg, 24.25 mmol) was added to a MeOH solution (25 ml) containing the intermediate from Step C (6.53 g, 18.66 mol). After stirring for 1 hour at room temperature the solution was concentrated and the residue partitioned between water and EtOAc. The organic phase was washed with water, brine and dried over Na 2 SO 4 . The filtered solution was concentrated to give the title compound as an 8:1 mixture of diastereomers which was used in the next step without further purification. 1 H NMR for major diastereomer (500 MHz, CDCl 3 ): δ 7.44 (d, J=8.1 Hz, 2H); 7.30 (d, J=8.5 Hz, 2H); 7.19 (d, J=8.5 Hz, 2H); 7.07 (d, J=8.1 Hz, 2H); 4.71-4.68 (m, 1H); 2.81-2.74 (m, 1H); 1.56-1.48 (m, 1H); 1.42-1.32 (m, 1H); 1.12-0.95 (m, 2H); 0.75 (t, J=7.3 Hz, 3H). LC1 4.00 min. (M-OH)=335
Step E. 1-Bromo-4-[2-(4-chlorophenyl)-1-propylpent-4-en-1-yl]benzene
The title compound was prepared from the intermediate from Step D using the conditions described in Step D. The title compound is obtained as a 2.1:1 mixture of diastereomers. 1 H NMR for major diastereomer (500 MHz, CDCl 3 ): δ 7.44 (d, J=8.5 Hz, 2H); 7.28 (d, J=8.3 Hz, 2H); 7.05 (d, J=8.2 Hz, 2H); 7.02 (d, J=8.4 Hz, 2H); 5.46-5.35 (m, 1H); 4.82-4.71 (m, 2H); 2.77-2.62 (m, 2H); 2.14-2.02 (m, 2H); 1.35-1.25 (m, 2H); 1.05-0.89 (m, 2H); 0.67 (t, J=7.3 Hz, 3H). LC1 4.66 min. Not ionized
Step F. n-Butyl 4-[2-(4-chlorophenyl)-1-propylpent-4-en-1-yl]benzoate
An n-butanol solution (5 ml) containing the intermediate from Step E (108 mg, 0.286 mmol), DIEA (0.15 ml, 0.86 mmol) and PdCl 2 (PPh 3 ) 2 (376 mg, 0.06 mmol) was heated at 115° C. under a carbon monoxide atmosphere (balloon). After 1 hour the solution was cooled and concentrated. The residue was dissolved in EtOAc and filtered. The residue was used without purification in the next step. A portion was purified for spectral analysis. 1 H NMR for major diastereomer (500 MHz, CDCl 3 ): δ 8.00 (d, J=8.3 Hz, 2H); 7.28 (d, J=8.4 Hz, 2H); 7.23 (d, J 8.3 Hz, 2H): 7.07 (d J=8.4 Hz, 2H); 5.42-5.31 (m, 1H); 4.77-4.66 (m, 2H); 4.33 (t, J=6.6 Hz, 2H); 2.80-2.75 (m, 2H); 2.10-2.06 (m, 2H); 1.81-1.68 (m, 2H); 1.41-1.24 (m, 4H); 0.99 (t, J=7.4 Hz, 3H); 0.98-0.86 (m, 4H); 0.67 (t, J=7.3 Hz, 3H). LC1 4.73 min. (M+H)=399
Step G. 4-[(1S,2R)-2-(4-chlorophenyl)-1-propylpent-4-en-1-yl]benzoic acid
A THF/MeOH/water (8 ml/8 ml/3 ml) solution containing the intermediate from Step F (790 mg, 1.98 mmol) and lithium hydroxide monohydrate (406 mg, 9.90 mmol) was stirred overnight at room temperature. The solution was concentrated and the nonvolatile portion was partitioned between aqueous 2N hydrochloric acid and EtOAc. The organic phase was dried over Na 2 SO 4 , filtered and concentrated to give the title compound. 1 H NMR (500 MHz, DMSO-d 6 ): δ 7.90 (d, J=8.2 Hz, 2H); 7.39 (d, J=8.5 Hz, 2H); 7.36 (d, J=8.5 Hz, 2H); 7.26 (d, J=8.4 Hz, 2H); 5.36-5.26 (m, 1H); 4.71-4.60 (m, 2H); 2.94-2.84 (m, 2H); 2.13-2.07 (m, 1H); 1.95-1.87 (m, 1H); 1.42-1.34 (m, 1H); 1.19-1.11 (m, 1H); 0.85-0.77 (m, 2H); 0.60 (t, J=7.3 Hz, 3H). LC3 2.57 min (M+H) 343
Alternatively, the title compound can be prepared from the intermediate from Step E. A pentane solution of t-BuLi (1.7M, 3.08 ml, 5.23 mmol) was added dropwise to a THF solution (20.1 ml) of the intermediate from Step E (760 mg, 2.01 mmol) cooled to −78° C. After 5 minutes, CO 2 gas was bubbled for a half minute through the solution. The cooling bath was removed and the solution was warmed to room temperature. The solution was then diluted with aqueous 2N HCl and extracted with EtOAc (2×). The combined organic phases were dried over Na 2 SO 4 , filtered and concentrated to give the title compound.
The absolute stereochemistry of the minor and major diastereomers of INTERMEDIATE 2 is shown below. This assignment is based on the known configuration of the n-propyl substituted carbon, which is derived from the (−)-pseudoephedrine, and NMR experiments (NOE). See WO2008/042223.
Intermediate 3
Methyl N-{4-[2-(4-chlorophenyl)-1-propylpent-4-en-1-yl]benzoyl}-β-alaninate
A DMF solution (20 ml) containing INTERMEDIATE 1 (1.66 g, 4.84 mmol), methyl β-alaninate hydrochloride (1.01 g, 7.26 mmol), DIEA (4.3 ml, 24.2 mmol) and BOP (3.21 g, 7.26 mmol) was stirred at room temperature for 1.5 hours. The solution was diluted with EtOAc and washed with water, brine and dried over Na 2 SO 4 . The filtered solution was concentrated and the residue purified by silica gel chromatography using a hexanes/EtOAc gradient to give the title compound. 1 H NMR for the major diastereomer (500 MHz, CDCl 3 ): δ 7.72 (d, J=8.2 Hz, 2H); 7.28 (d, J=8.3 Hz, 2H); 7.22 (d, J=8.2 Hz); 7.07 (d, J=8.4 Hz, 2H); 6.85-6.81 (m, 1H); 5.41-5.31 (m, 1H); 4.77-4.66 (m, 2H); 3.75-3.70 (m, 2H); 3.73 (s, 3H); 2.81-2.72 (m, 2H); 2.67 (t, J=5.9 Hz, 2H); 2.10-2.05 (m, 2H); 1.40-1.29 (m, 2H); 0.98-0.85 (m, 2H); 0.66 (t, J=7.3 Hz, 3H). LC1 4.03 min. (M+H)=428
Intermediate 4
Methyl N-{4-[2-(4-chlorophenyl)-4-oxo-1-propylbutyl]benzoyl}-β-alaninate
Ozone was purged through a chilled (−78° C.) DCM solution (20 ml) containing INTERMEDIATE 3 (1.59 g, 3.72 mmol). The ozone purge was maintained until an excess of ozone was observed (blue color, <10 minutes). The solution was then purged with nitrogen to dissipate the excess ozone. To the solution was added dimethylsulfide (1 ml) followed by triphenylphosphine (977 mg, 3.72 mmol). The solution was warmed to room temperature and stirred for approximately 2 hours. The solution was concentrated and the residue purified by silica gel chromatography using a hexanes/EtOAc gradient to give the title compound. 1 H NMR for the major diastereomer (500 MHz, CDCl 3 ): δ 9.34 (s, 1H); 7.73 (d, J=8.2 Hz, 2H); 7.30 (d, J=8.3 Hz, 2H); 7.23 (d, J=8.0 Hz, 2H); 7.16 (d, J=8.4 Hz, 2H); 6.87-6.83 (broad s, 1H); 3.72 (s, 3H); 3.75-3.71 (m, 2H); 3.36-3.31 (m, 1H); 2.80-2.72 (m, 1H); 2.69-2.63 (m, 2H); 2.61-2.52 (m, 1H); 2.38 (dd, J=3.9, 17.1 Hz, 1H); 1.45-1.28 (m, 2H); 1.06-0.78 (m, 2H); 0.66 (t, J=7.3 Hz, 3H). LC1 3.55 min. (M+H)=430
Example 1
N-(4-{(1S)-1-[(R)-(4-chlorophenyl)(7-fluoro-5-methyl-1H-indol-3-yl)methyl]butyl}benzoyl)-β-alanine
Step A. Methyl N-(4-{(1S)-1-[(R)-(4-chlorophenyl)(7-fluoro-5-methyl-1H-indol-3-yl)methyl]butyl}benzoyl)-β-alaninate (Compound A)
An acetic acid solution (10 ml) of methyl N-{4-[2-(4-chlorophenyl)-4-oxo-1-propylbutyl]benzoyl}-β-alaninate, INTERMEDIATE 4, (757 mg, 1.76 mmol), ZnCl 2 (3.1M in AcOH, 1.7 ml, 5.27 mol) and 2-fluoro-4-methylphenylhydrazine hydrochloride (374 mg, 2.1 mmol) was heated at 80° C. for 45 minutes. The solution was concentrated and the residue partitioned between EtOAc and water. The organic phase was washed with water (2×), brine (2×) and dried over Na 2 SO 4 . The solution was filtered, concentrated and the residue purified by silica gel chromatography using a hexanes/ethyl acetate gradient to give the title compound. Data for the major diastereomer: 1 H NMR (500 MHz, CD3CN): δ 9.11 (s, 1H); 7.54 (d, J=8.2 Hz, 2H); 7.48 (d, J=8.5 Hz, 2H); 7.38 (d, J=8.2 Hz, 2H); 7.30 (d, J=8.4 Hz, 2H); 7.15 (d, J=2.5 Hz, 1H); 7.11 (s, 1H); 7.02-6.97 (m, 1H); 6.59 (d, J=12.3 Hz, 1H); 4.49 (d, J=11.6 Hz, 1H); 3.60 (s, 3H); 3.56-3.48 (m, 3H); 2.52 (t, J=6.8 Hz, 2H); 2.32 (s, 3H); 1.49-1.35 (m, 2H); 1.04-0.90 (m, 2H); 0.69 (t, J=7.4 Hz, 3H). LC1=3.94 min. (M+H)=535. Chiral LC1 (1% to 15% EtOH/heptane over 25 min, 15% EtOH/heptane isocratic >25 min) retention time=28.38 minutes. The material also contains ca 2% by area of the enantiomer. Chiral LC1 (1% to 15% EtOH/heptane over 25 min, 15% EtOH/heptane isocratic >25 min) retention time=26.88 minutes.
Step B. N-(4-{(1S)-1-[(R)-(4-Chlorophenyl)(7-fluoro-5-methyl-1H-indol-3-yl)methyl]butyl}benzoyl)-β-alanine
The isomers obtained in Step A were hydrolyzed using the conditions described in INTERMEDIATE 2, Step G. The crude hydrolysis was purified by HPLC to give the title compounds.
Data for the Minor Diastereomer:
1 H NMR (400 MHz, CD 3 CN): δ 9.39 (s, 1H); 7.56 (d, J=8.0 Hz, 2H); 7.37 (d, J=2.4 Hz, 1H); 7.33 (s, 1H); 7.29 (d, J=8.0 Hz, 2H); 7.20 (d, J=8.4 Hz); 7.07 (broad s, 1H); 7.01 (d, J=8.4 Hz, 2H); 6.72 (d, J=12.4 Hz, 1H); 4.45 (d, J=11.6 Hz); 3.65-3.55 (m, 1H); 3.52 (q, J=6.4 Hz, 2H); 2.55 (t, J=6.8 Hz, 2H); 2.40 (s, 3H); 1.84-1.73 (m, 1H); 1.63-1.52 (m, 1H); 1.10-0.93 (m, 2H); 0.71 (t, J=7.2 Hz, 3H). LC1=3.66 min. (M+H)=521.
Data for the major diastereomer: 1 H NMR (500 MHz, CD 3 CN): δ 9.11 (s, 1H); 7.56 (d, J=8.2 Hz, 2H); 7.49 (d, J=8.4 Hz, 2H); 7.39 (d, J=8.2 Hz, 2H); 7.31 (d, J=8.4 Hz, 2H); 7.16 (d, J=2.4 Hz, 1H); 7.12 (s, 1H); 7.04 (s, 1H); 6.60 (d, J=12.2 Hz, 1H); 4.50 (d, J=11.6 Hz, 1H); 3.58-3.53 (m, 1H); 3.50 (q, J=6.4 Hz, 2H); 2.53 (t, J=6.6 Hz, 2H); 2.33 (s, 3H); 1.51-1.37 (m, 2H); 0.99-0.92 (m, 2H); 0.70 (t, J=7.3 Hz, 3H). LCMS1 3.83 min. (M+H)=521. [α]=−126.6° (589 nm, EtOH)
Alternative synthetic schemes for Compound A are included herein as well.
Example 2
1. Preparation of Compound 1
4-Bromobenzoyl chloride (106.0 kg, 482.9 mol) was dissolved in THF (479 L) and cooled to −5˜0° C. Potassium tert-butoxide (75.8 kg, 675.5 mol) was dissolved in THF (565 L) to give a hazy solution, which was cooled to −5° C. and added over 5 h to the acid chloride solution via an inline filter so that the temperature was maintained below 5° C.
After 30 minutes, the reaction was assayed for completion by HPLC (<2% starting material). In a separate vessel, NaCl (40 kg) was dissolved in water (736 L), then heptane (886 L) charged and the mixture was cooled to −5° C. The reaction mixture was added over 5 h to the aqueous mixture maintaining below 5° C. The reaction vessel was rinsed with heptane (88 L) and combined with the batch. After layer separation, the aqueous was back-extracted with heptane (294 L). The combined organic layer was washed twice with 426 L water until pH 7, and dried over anhydrous MgSO 4 (15.9 kg). The filtrate was concentrated to ˜230 L in vacuum at 30-40° C. Charged THF (609 kg) and concentrated to ˜230 L. This was repeated until water<0.05% water and <12% heptane.
1 H NMR (400 MHz, CDCl 3 ) δ 7.85 (d, J=8.7 Hz, 2H), 7.55 (d, J=8.7 Hz, 2H), 1.60 (s, 3H).
13 C NMR (100 MHz, CDCl 3 ) δ 165.2, 131.7, 131.2, 131.1, 127.6, 81.7, 28.4.
Anal. Calcd for C 11 H 13 BrO 2 : C, 51.38; H, 5.10; Br, 31.08. Found: C, 51.61; H, 5.09; Br, 31.35.
2. Preparation of Compound 3
Sodium tert-butoxide (53.0 kg) in THF (404.6 kg) was de-gassed via three N 2 /vacuum purge cycles and agitated for 15 minutes until the solid was dissolved at 15-20° C. Palladium acetate (454 g), and DPEphos (1081 g) were then charged under nitrogen. The batch was de-gassed again via three N 2 /vacuum purge cycles and aged for 10 minutes.
4-Chlorovalerophenone (2) (79.0 kg; flushed with THF to remove residual MeOH and H 2 O until <0.35% water), tert-butyl bromobenzoate 1 (160.7 kg), and THF (66.0 kg) were then added, and the batch was de-gassed again via three N 2 /vacuum purge cycles. The batch was then heated to 58-64° C. for 8 hours and then checked by HPLC for completion (<2% 3).
After cooling to 15-25° C., the batch was quenched into a 0-5° C. mixture of heptane (730.7 kg) and sodium bicarbonate solution (prepared by dissolving 42.8 kg sodium bicarbonate in 808 L water), keeping at 0-10° C. The reaction vessel was rinsed with heptane (40.5 kg) and combined with the mixture. The mixture was warmed to 15-25° C. and the phases separated.
The aqueous phase was back extracted with heptane (385.0 kg). The combined organics were poured into a pH 8.5 aqueous solution made up with 2-mercaptobenzoic acid (32.0 kg), water (354 kg) and stirred at 25-30° C. for 6-8 h. After layer separation, the organic phase was washed twice with 3% Na 2 CO 3 solution (549 kg each time). Analysis of the organic layer indicated that the residual 2-mercaptobenzoic was <0.05%. The organic was washed twice with water (426 kg each time) until pH 7, and further washed twice with 20% NaCl solution (476 kg each time).
A silica plug was prepared in the filter using 50 kg silica 60 wet with cold heptane and topped with anhydrous Na 2 SO 4 . The organic batch was then filtered through the silica gel, and washed with heptane (79.1 kg).
The combined filtrates were concentrated to 160 L yellow oil under vacuum at batch temperature<40° C. 2-Propanol (930 kg) was added and the mixture was concentrated to 160 L. Added 2-propanol (620.9 kg) and concentrated to 160 L at <40° C. The oil was diluted with 2-propanol (231 kg), and warmed to 45-60° C. After stirring for 15 min, H 2 O (93 kg) was slowly added at 40-60° C. to the slurry, then allowed it to slowly cool to 22° C. The slurry was then cooled to −5-5° C., aged for 2 h, filtered and washed with 50 kg 2:1 2-propanol/water.
The wet cake was dried under vacuum at 38-40° C./22 in. Hg/N 2 for 22 h to yield product 2 as an off-white solid.
1 HNMR (400 MHz, CDCl 3 ) δ 7.92 (m, 2H), 7.87 (m, 2H), 7.36 (m, 2H), 7.33 (m, 2H), 4.54 (t, J=7.2 Hz, 1H), 2.16 (m, 1H), 1.83 (m, 1H), 1.57 (s, 9H), 1.37-1.17 (m, 2H), 0.92 (t, J=7.3 Hz, 3H).
13 C NMR (100 MHz, CDCl 3 ) δ 198.4, 165.6, 144.3, 139.6, 135.2, 131.2, 130.3, 130.2, 129.1, 128.3, 81.2, 53.7, 36.0, 28.4, 20.9, 14.2.
Anal. Calcd for C 22 H 25 ClO 3 : C, 70.86; H, 6.76; Cl, 9.51. Found: C, 70.73; H, 6.98; Cl, 9.21.
HPLC conditions: Zorbax Eclipse XDB-C8, 4.6×150 mm; A: 0.1% H 3 PO 4 aqueous; B: acetonitrile; 70% to 95% B over 15 min, hold 2 min, post time 4 min. 1.0 mL/min, 10 μL, 210 nm, 30° C. column temperature; p-chlorovalerophenone, RT=4.36 min; tert-butyl 4-bromobenzoate, RT=5.56 min; product, RT=9.74 min; product acid, RT=3.26 min.
Note: The catalyst used above can be replaced with BINAP or tol-BINAP.
3. Preparation of Compound 4
Ketone 3 (110 kg) in IPA (682 kg) was charged to the hydrogenation vessel, and the solution was thoroughly de-gassed using N 2 /vacuum purge cycles.
The catalyst solution was prepared in a separate vessel: potassium tert-butoxide (7.0 kg) was dissolved in IPA (66 kg) and thoroughly purged with N 2 . The catalyst Ru[(S)-XYL-SEGPHOS][(S)-DIAPEN] (551 g) was added, the catalyst mixture aged for 1 hour at 25-30° C., whilst purging with N 2 . This catalyst preparation was then added to the ketone IPA solution, taking care to exclude air during this operation, and de-gassing using N 2 /vacuum purge cycles after the addition. The batch was then hydrogenated for 3-5 hours at 20-25° C. using a H 2 pressure of 0.64-0.68 Mpa.
The reaction solution was passed through silica gel column (46.4 kg) two times. The filtrate was concentrated to ˜880 L by distillation at <40° C. The solution was then heated to 55-58° C., and slowly added water (780 kg) over 1.5 h at the same temperatures. After stirring for 1-1.5 h, the mixture was cooled to 20-25° C. over 2-3 h. The slurry was aged for 2-3 h, then cooled to 0-5° C. over 2-3 h. After stirring for 1-2 h, the slurry was filtered, and the cake was washed twice with cold 2:1 IPA:water (230 kg).
The wet cake was dried in 40-45° C. vacuum for 28-30 h, to give the product 4 as an off-white solid.
1 H NMR (400 MHz, CDCl 3 ) δ 7.96 (m, 2H), 7.32 (m, 2H), 7.26 (m, 2H), 7.22 (m, 2H), 4.76 (dd, J=7.7, 2.9 Hz, 1H), 2.89 (ddd, J=11.5, 7.7, 4.2 Hz, 1H), 1.84 (d, J=2.9 Hz, —OH), 1.62 (s, 9H), 1.61 (m, 1H), 1.41 (m, 1H), 1.05 (m, 2H), 0.76 (t, J=7.3 Hz, 3H).
13 C NMR (100 MHz, CDCl 3 ) δ 165.9, 146.3, 141.4, 133.7, 131.0, 129.8, 128.9, 128.7, 128.4, 81.1, 78.01, 54.2, 34.2, 28.4, 20.6, 14.1.
Anal. Calcd for C 22 H 27 ClO 3 : C, 70.48; H, 7.26; Cl, 9.46. Found, C, 70.45; H, 7.40; Cl, 9.24.
Zorbax Eclipse XDB-C8, 4.6×150 mm; A: 0.1% H 3 PO 4 aqueous; B: acetonitrile; 70% to 95% B over 15 min, hold 2 min, post time 4 min. 1.0 mL/min, 10 μL, 210 nm, 30° C. column temperature; Major diastereomer, RT=7.74 min; minor diastereomer, RT=6.89 min; Major diastereomer acid, RT=2.66 min; minor diastereomer acid, RT=2.27 min.
Chiral SFC Method: Chiralpak AD-H (250×4 6 mm), isocratic 15% MeOH/CO 2 , 1.5 mL/min, 200 bar, 35° C., 215 nm, 15 min: desired alcohol, RT=9.8 min; enantiomeric alcohol, RT=10.6 min.; diastereomeric alcohols: 5.2 & 6.3 min.
4. Preparation of Compound 5
Alcohol 4 (90 kg) was slurried in acetonitrile (600 kg) and orthophosphoric acid (85 wt %, 113.6 kg) charged followed by 60 kg acetonitrile for chasing orthophosphoric acid. The slurry was inerted with N 2 and heated to 62-68° C., monitoring hourly for conversion.
After 3.5-4 h, reaction was complete by HPLC. The solution was cooled to 55-65° C. and water (98 kg) charged over 45 minutes to effect crystallization. The mixture was cooled to 45-50° C., and seeded with 430 g compound 5 to effect crystallization if crystallization has not occurred. Once a seedbed was established at 45-50° C., further water (861 kg) was charged, and stirred for 1-2 h at these temperatures. The slurry was cooled slowly to 20-25° C., and then aged for 2-3 h. The product was filtered and washed with 88 kg of 3:1 H 2 O/CH 3 CN.
The wet cake was dried under vacuum at 38-40° C. for 10-16 h to afford product 5 as a yellow solid as a mono-hydrate.
1 H NMR (400 MHz, DMSO-d 6 ) δ 12.71 (br s, —CO 2 H), 7.79 (d, J=8.3 Hz, 2H), 7.29 (d, J=8.4 Hz, 2H), 7.19-7.25 (m, 4H), 5.32 (br s, —OH), 4.76 (d, J=6.3 Hz, 1H), 2.85 (dt, J=10.7, 5.4 Hz, 1H), 1.61 (m, 1H), 1.44 (m, 1H), 1.00 (m, 2H), 0.73 (t, J=7.3 Hz, 3H).
13 C NMR (100 MHz, DMSO-d 6 ) δ 167.4, 147.7, 143.7, 131.0, 129.1, 128.6, 128.4, 128.3, 127.6, 75.1, 52.7, 34.0, 20.0, 13.8.
Anal. Calcd for C 18 H 19 ClO 3 .H 2 O: C, 64.19; H, 6.28; Cl, 10.53. Found: C, 64.43; H, 6.06; Cl, 10.30.
Zorbax Eclipse Plus C18, 4.6×50 mm; A: 0.1% H 3 PO 4 aqueous; B: acetonitrile; 75% to 95% B over 4 min, hold 1 min, post time 2 min. 1.5 mL/min, 3 μL, 210 nm, 22° C. column temperature; starting material, RT=2.49 min; product, RT=0.65 min.
Chiral HPLC Method: ChiralPak IB (250×4.6 mm), 0.1% TFA in heptane, B=0.1% TFA in 50/50 EtOH/MeOH, isocratic 6% B, 1.0 mL/min, 10 μL of 1.5 mg/mL EtOH, 25° C., 254 nm, 30 min: major enantiomer, RT=17.10 min; minor enantiomer, RT=21.22 min.
5. 2-Bromo-6-fluoro-4-methylaniline 7
6-fluoro-4-methylaniline 6 (15 kg) was added to a mixture of MTBE (92 L, 66.6 kg) calcium carbonate (12 kg) and water (135 kg), inerted and cooled to <5° C. Bromine (18.22 kg) was charged, keeping T<10° C. Age for 30 minutes at T<10° C. The batch was warmed to ˜18° C. and allowed to settle.
The lower aqueous layer was cut away and the organics washed with 5% aq sodium metabisulfite (75 L) then water (75 L). The organic phase was solvent-switched to toluene (at <40° C. using vacuum), final volume 45-60 L, then passed through a silica pad (15 kg) in an oyster filter, washing with toluene (60 L, 52 kg). The filtrates were combined and reduced by vacuum distillation (T<40° C.).
6. 7-Fluoro-5-methyl-1H-indole 8
Method 1:
Palladium allyl chloride dimer (0.74 kg) and DPE Phos (2.17 kg) were slurried in heptane (165 L, 113 kg) and de-gassed using N 2 /vacuum cycles. Dicyclohexylamine (7.85 kg) was added, de-gassed again using N 2 /vacuum cycles, and the resulting suspension was aged for no more than 40 minutes.
In another vessel, the bromoaniline 7 (16.5 kg as a 20 wt % toluene solution), dicyclohexylmethylamine (36.2 kg) and trimethylsilyl acetylene (15.1 kg) were de-gassed using N 2 /vacuum cycles. The catalyst suspension was then transferred into this vessel over 5 minutes, and the vessel was pressurised to 2300 mbar and heated to 70° C. overnight.
After 17 hours, HPLC analysis showed no starting material present. The batch was cooled to 20° C. and filtered through ˜3 kg Solka-Floc in an oyster filter. Heptane (30 L) was used to rinse the vessel then wash the filter cake. The filtrate and wash were combined and washed with HCl (made up with 15.4 kg conc. HCl and 75 kg water), then water (80 kg).
50 kg silica was loaded into the large oyster filter and wetted with cold heptane (100 L). The organics were then filtered through the silica, washing/eluting with toluene/heptane (21 kg/38 kg) then toluene (55 kg). The filtrate fractions were combined and distilled to a volume of 90 L under reduced pressure with maximum batch temperature of 50° C.
Tetrabutylammonium fluoride trihydrate (27.8 kg) was dissolved in THF (79 kg) and methanol (4.1 L), and the indole toluene solution added to it over 5 minutes. The solution was heated to 80-85° C. and THF removed by atmospheric distillation.
Once reaction was complete, distillation was continued at 100-150 mbar to remove residual THF. The batch was then cooled to 20° C. and washed with 5 wt % brine (44 kg). The brine wash was extracted with toluene (42 kg). The combined toluene organics were then washed with 5 wt % brine. The organics were filtered and the filtrate concentrated to give a toluene solution of indole 8.
1 H NMR (400 MHz, CDCl 3 ) δ 8.20 (br s, —NH), 7.22 (d, J=0.6 Hz, 1H), 7.20 (dd, J=2.9, 2.7 Hz, 1H), 6.78 (dd, J=12.0, 0.7 Hz, 1H), 6.52 (ddd, J=3.3, 3.3, 2.2 Hz, 1H), 2.46 (s, 3H).
13 C NMR (100 MHz, CDCl 3 ) δ 149.4 (d, J=242.9 Hz), 131.8 (d, J=5.5 Hz), 130.2 (d, J=5.7 Hz), 125.0, 122.6 (d, J=13.2 Hz), 116.1 (d, J=3.1 Hz), 108.6 (d, J=15.7 Hz), 103.0 (d, J=2.3 Hz), 21.6.
19 F NMR (376 MHz, CDCl 3 ) δ −136.5.
Anal. Calcd for C 9 H 8 FN: C, 72.47; H, 5.41; F, 12.74; N, 9.39. Found: C, 72.15; H, 5.34; F, 12.74; N, 9.28.
Zorbax Eclipse XDB-C8, 4.6×150 mm; A: 0.1% H 3 PO 4 aqueous; B: acetonitrile; 70% to 95% B over 15 min, hold 2 min, post time 4 min. 1.0 mL/min, 10 μL, 210 nm, 30° C. column temperature; product, RT=2.67 min.
Method 2:
Step 1: Sugasawa Reaction
Reagent
MW
Amount
mmol
Equiv.
2-Fluoro-4-methylaniline
125.15
12.52
g
100
2.00
Chloroacetonitrile
75.5
3.78
g
50
1.00
BCl 3 /CH 2 Cl 2 (1.0M)
110
mL
110
2.20
AlCl 3 pellet
133.34
8.00
g
60
1.20
1,2-Dichloroethane (DCE)
125
mL
10 V of
aniline
HCl (2.0M in water)
80
mL
160
Product-chloroacetophenone
201.63
10.08
g
50
100%
A vessel was cooled via ice bath, was charged with AlCl 3 pellets, 100 mL DCE, and BCl 3 /DCM solution 110 mL under N 2 with an outlet into an aqueous NaOH solution bath. A solution of SM-aniline was then added dropwise with caution to keep t<20 C. Upon completion, the grey slurry was added SM-nitrile in one portion, and extra DCE was used to rinse the RBF. The ice bath was removed, and the reaction was heated to reflux.
After 6 h of reflux, the mixture was cooled, quenched with 2N HCl 80 mL, and heated to reflux for 20 min. The mixture was extracted with DCM, washed with 2N HCl, water, and brine. After concentration, the solid was stirred with 25 mL hexanes, cooled via an ice bath, filtered, and washed with extra 50 mL hexanes, A dark yellow solid was obtained.
The combined HCl wash was treated with NaOH (pellets, 14.7 g) to pH=5-6, extracted with MTBE/Heptane (1:1) and concentrated.
Step 2: Reduction and Cyclization
Reagent
MW
Amount
mmol
Equiv.
chloroacetophenone (96.6%)
201.63
2033
mg
9.74
1.00
NaBH 4
37.83
456
mg
12.0
2.46
1,4-Dioxane
20
mL
10 V
Water
2.0
mL
1 V
Product-indole
149.16
1453
mg
9.74
100%
Chloroacetophenone was dissolved in dioxane followed by addition of NaBH 4 and water. The mixture was aged at room temperature for 25 min before heated to reflux for 2 h, cooled to room temperature, worked up with MTBE and water. Concentration of the workup gave a brown clear liquid, which solidified upon freezing.
The formed indole was used to prepare nosyl indole as a white solid powder after recrystallization from MeCN/water (2:1).
7. 7-Fluoro-5-methyl-1-[(4-nitrophenyl)sulfonyl]-1H-indole 8
Indole 8 (3.2 kg as a 10 wt % solution in toluene) was distilled to a volume of 90 L under reduced pressure with a maximum batch temperature of 50° C. 48 wt % sodium hydroxide (15 kg, 9.6 L) was charged. The batch was cooled to 15° C. and tetrabutylammonium sulphate (363 g) added. Nosyl chloride (5.92 kg) was dissolved in toluene (15.6 kg) and the solution charged slowly, keeping T<25° C. After 10 minutes, HPLC analysis showed complete reaction.
Cold (10° C.) 5 wt % sodium hydrogen carbonate solution (45 L) was charged and the phases separated. The organics were washed with 5 wt % sodium hydrogen carbonate solution (31 L), and then washed with HCl (30 kg water & 730 mL conc HCl). The organics were distilled to a volume of ˜45 L under reduced pressure with maximum batch temperature of 40° C. Isopropanol (35 kg, 45 L) was added, and the solution passed through the CUNO carbon filtration system, using a 3.5 kg R-55SLP cartridge.
Isopropanol (19.3 kg, 25 L) was added to the filtrate and it was distilled under reduced pressure with maximum batch temperature of 40° C., adding additional isopropanol until <10 mol % toluene is present by NMR, to a final volume of ˜10 wt % product in IPA. The batch was cooled to 5° C. to crystallise the product. The slurry was filtered, and washed with isopropanol (30 L, 24 kg), then cold IPA/water (24 kg/1.5 kg). The solid was dried on the filter under a nitrogen stream to give the product 9 as a brown solid.
1 H NMR (400 MHz, CDCl 3 ) δ 8.32 (d, J=8.8 Hz, 1H), 8.11 (d, J=8.8 Hz, 1H), 7.70 (d, J=3.7 Hz, 1H), 7.13, (s, 1H), 6.81 (d, J=13.1 Hz, 1H), 6.66 (dd, J=3.5, 2.4 Hz, 1H), 2.38 (s, 3H);).
13 C NMR (100 MHz, CDCl 3 ) δ 150.8, 149.2 (d, J=249.2 Hz), 144.1, 135.5 (d, J=6.5 Hz), 135.3 (d, J=3.8 Hz), 129.2 (d, J=2.8 Hz), 128.7, 128.6, 120.0 (d, J=11.2 Hz), 117.6 (J=3.4 Hz), 113.1 (d, J=19.4 Hz), 109.1 (d, J=2.1 Hz).
Anal. Calcd for C 15 H 11 FN 2 O 4 S: C, 53.89; H, 3.32; F, 5.68; N, 8.38; 0, 19.14; S, 9.59. Found: C, 53.68; H, 3.16; F, 5.58; N, 8.30; S, 9.64.
Zorbax Eclipse XDB-C8, 4.6×150 mm; A: 0.1% H 3 PO 4 aqueous; B: acetonitrile; 70% to 95% B over 15 min, hold 2 min, post time 4 min. 1.0 mL/min, 10 μL, 210 nm, 30° C. column temperature; starting indole, RT=2.49 min; N-(4-nosyl)-indole, RT=3.74 min.
8. 4-[(1S)-1-((R)-(4-Chlorophenyl) {7-fluoro-5-methyl-1-[(4-nitrophenyl)sulfonyl]-1H-indol-3-yl}methyl)butyl]benzoic acid 10
Method 1:
Acid 5 (8.2 kg of 98 wt %) and nosyl indole 9 (8.86 kg, 96 wt %) were slurried in dichloromethane (160 kg), inerted and cooled to 15° C. BF 3 OEt 2 (10.74 kg) was charged, keeping T<25° C. The brown solution was aged at 20° C. for 18 h, then cooled to 15° C. and water (80 kg) added.
The biphasic mixture was filtered through a pad of Solka-Floc (˜5 kg) contained in an oyster filter, and the pad was washed with 10 kg dichloromethane. The filtrate was separated and the lower DCM organic washed with water (80 kg).
The DCM organics were then stirred gently overnight with MP-TMT resin (2.4 kg), then filtered, washing with IPAC (30 L).
The filtrate volume was then reduced by vacuum distillation (T<35° C.). Isopropyl acetate (105 kg) was added, and this solution was filtered, washing with IPAC and DCM.
The IPAC solution was warmed to 50° C. and heptane (38 kg) charged, keeping T at approximately 45° C. Seed (10 g) was charged, and the batch cooled to 20° C. overnight (using a linear ramp on the PCS system). Further seeding or heptane addition caused crystallisation.
The product was dried in vacuo to give 9 as a tan solid.
Method 2:
To a mixture of alcohol 5 (42.7 kg, 93.7 wt %) and indole 9 (41.3 kg, 99.5 wt %) was added trifluoroacetic acid (943 kg) and methanesulfonic acid (6.0 kg). After stirring for 19 h at 22° C., the solution was diluted with isopropyl acetate (1070 kg) (temperature controlled from 10-25° C.), cold 20 wt % NaOH (1200 kg), and 15 wt % K 2 HPO 4 (1430 kg). After separating the layers, the organic was pH adjusted to a pH of 2 with 0.1 N HCl (136 kg). After separating the layers, the organic was washed with water (1207 kg).
The organic phase was filtered and then washed with IPAC. The organic phase was concentrated and flushed with IPAC to remove water (target: <200 ug/mL).
The batch was seeded with 0.5 wt % (relative to products) at 35° C. and aged for 60 min, then cooled 20° C. over 1 h to allow a seed bed to develop. Heptane was added over 300 min. The slurry was filtered, washed with 1:4 IPAC/heptane (430 kg), and vacuum dried at 40° C. overnight to afford product 10 as a tan solid.
4-[(1S)-1-((R)-(4-chlorophenyl){7-fluoro-5-methyl-1-[(4-nitrophenyl)sulfonyl]-1H-indol-3-yl}methyl)butyl]benzoic acid-isopropyl acetate (1:1)
Major Diastereomer:
1 H NMR (400 MHz, CDCl 3 ) δ 8.13 (d, J=8.9 Hz, 2H), 8.05 (d, J=8.3 Hz, 2H), 7.52 (d, J=8.7 Hz, 2H), 7.45 (s, 1H), 7.40 (d, J=8.3 Hz, 2H), 7.38-7.31 (m, 4H), 6.89 (s, 1H), 6.68 (d, J=12.8 Hz, 1H), 4.32 (d, J=11.5 Hz, 1H), 3.43 (dt, J=10.8, 3.5 Hz, 1H), 3.29 (s, 3H), 1.55 (m, 1H), 1.47 (m, 1H), 1.06 (m, 2H), 0.76 (t, J=7.3 Hz, 3H).
13 C NMR (100 MHz, CDCl 3 ) δ 171.4, 151.0, 150.7, 149.1 (d, J=250.6 Hz), 143.4, 140.1, 135.4 (d, J=6.4 Hz), 134.9 (d, J=3.2 Hz), 133.1, 130.7, 129.9, 129.3, 128.6, 128.5, 127.7, 127.7, 126.4 (d, J=3.2 Hz), 124.5, 124.4, 119.8 (d, J=11.1 Hz), 115.5, 113.5 (d, J=19.3 Hz), 50.5, 47.7, 37.4, 21.4, 20.4, 14.1.
1 H NMR (400 MHz, DMSO-d 6 ) δ 8.23 (d, J=8.8 Hz, 2H), 7.95 (s, 1H), 7.83 (d, J=8.2 Hz, 2H), 7.70-7.60 (m, 4H), 7.57 (d, J=8.2 Hz, 2H), 7.39 (d, J=8.4 Hz, 2H), 7.27 (s, 1H), 6.83 (d, J=13.2 Hz, 1H), 4.61 (d, J=11.8 Hz, 1H), 3.80 (dt, J=11.6, 3.2 Hz, 1H), 2.25 (s, 3H), 1.45 (m, 1H), 1.29 (m, 1H), 0.93 (m, 2H), 0.68 (t, J=7.3 Hz, 3H).
13 C NMR (100 MHz, DMSO-d 6 ) δ 171.8, 167.2, 150.4, 149.9, 148.2 (d, J=250.0 Hz), 141.7 (d, J=30.3 Hz), 135.0 (d, J=6.5 Hz), 134.8 (d, J=3.2 Hz), 131.1, 130.2, 129.1, 128.5, 128.4, 128.3, 128.1, 126.8, 125.5 (d, J=1.6 Hz), 124.7, 118.5 (d, J=10.3 Hz), 115.7, 112.7 (d, J=19.5 Hz), 47.9, 45.8, 36.7, 20.6, 19.7, 13.6.
19 F NMR (376 MHz, CDCl 3 ) δ −122.8.
Anal. Calcd for C 38 H 38 C1FN 2 O 8 S: C, 61.91; H, 5.20; Cl, 4.81; F, 2.58; N, 3.80; S, 4.35. Found: C, 62.04; H, 5.09; N, 3.79; Cl, 4.82; F, 2.63; S, 4.47.
Minor Diastereomer:
Selective NMR signals: 1 H NMR (400 MHz, CDCl 3 ) δ 8.32 (d, J=8.9 Hz, 2H), 8.08 (d, J=8.9 Hz, 2H), 7.94 (d, J=8.2 Hz, 2H), 7.72 (s, 1H), 7.16 (d, J=8.2 Hz, 2H), 7.07 (s, 1H), 7.05 (d, J=8.5 Hz, 2H), 6.98 (d, J=8.5 Hz, 2H), 6.68 (d, J=12.8 Hz, 1H), 4.27 (d, J=10.8 Hz, 1H), 3.47 (m, 1H), 2.37 (s, 3H), 1.85 (m, 1H), 1.20 (m, 1H), 1.15 (m, 2H), 0.83 (t, J=7.3 Hz, 3H); 19 F NMR (376 MHz, CDCl 3 ) δ −122.3; Anal. Calcd for C 33 H 28 C1FN 2 O 6 S.0.5 MTBE.0.2 heptane: C, 63.38; H, 5.36; N, 4.01; Cl, 5.07; F, 2.72; S, 4.59. Found: C, 63.59; H, 5.36; N, 3.84; Cl, 4.94; F, 2.75; S, 4.61.
Zorbax Eclipse XDB-C8, 4.6×150 mm; A: 0.1% H 3 PO 4 aqueous; B: acetonitrile; 70% to 95% B over 15 min, hold 2 min, post time 4 min. 1.0 mL/min, 10 μL, 210 nm, 30° C. column temperature; Major diastereomer, RT=7.23 min; minor diastereomer, RT=5.66 min; 3-tert-butylated indole 5, RT=6.69 min.
Chiral SFC Method: ChiralPak IB column (250×4.6 mm), isocratic 25% MeOH w 0.1% TFA/CO2, 1.5 ml/min, 200 bar, 35 C, 35 min; Enantiomer of desired (R,S), RT=17.28; Desired (S,R), RT=18.11 min; Diastereomer of desired (S,S), RT=19.85 min; Enantiomer of diastereomer of desired (R,R), RT=24.15 min.
9. 3-[(4-{(1S)-1-[(R)-(4-chlorophenyl)(7-fluoro-5-methyl indol-3-yl)methyl]butyl}benzoyl)amino]-propanoic acid 12
Penultimate compound 10 (7.40 kg) was dissolved in THF (32.9 kg) and degassed using N 2 /vacuum purge cycles. N,N-carbonyldiimidazole (2.64 kg) was charged, and the batch was warmed to 40° C. for 45 minutes. HPLC showed complete conversion to acylimidazolide.
The batch was cooled to 30° C. and β-alanine methyl ester (2.60 kg) added. The batch was then heated to 60° C. for 4 hours. HPLC analysis showed complete conversion to amide/ester.
2.5 M NaOH (32.6 L; prepared from 5.70 kg 10 M NaOH and 24.5 kg water) was charged and the batch aged at 60° C. for 1.5 h, then further 10 M NaOH (1.63 kg) added and the batch aged at 60° C. overnight. The batch was cooled to 25° C. and the lower aqueous layer cut away. Further water (14.1 kg) and 10 M NaOH (2.78 kg) were charged, and the batch heated to 60° C. for 2 hours.
The batch was cooled to 25° C. and MTBE (48.8 L, 36.1 kg) charged, then 5 wt % NaCl (2.44 kg NaCl in 48.8 kg water). After agitation and settling, the phases were separated and the organics washed with 5 wt % NaCl (2.44 kg NaCl in 48.8 kg water), 3 M HCl (2.68 kg conc. HCl in 9.8 kg water) and water (48.8 kg).
The organics were concentrated to a volume of 15 L using vacuum with a maximum batch temperature of 30° C. Isopropanol (47.4 L, 37.2 kg) was then added and the batch concentrated to 15 L again. Isopropanol (27 L, 21 kg) was added and the solution was filtered, washing with isopropanol. The filtrate was then vacuum distilled with maximum batch temperature of 30° C. Water (26.6 kg) was added, seed added and the slurry aged for 45 minutes.
The slurry was filtered, washing with IPA/water (4.6 kg/11.8 kg) then water (35 kg). The solid was dried.
The cake was transferred to a vacuum oven at 42° C. for 24 h. The dried solids were passed through a co-mill to give product 12 (98.7 LCAP, 101 LCWP) as an off-white solid.
Amorphous Material
The amorphous phase of compound A was obtained by lyophilization. It can also be obtained by other techniques such as spraying drying and melt quenching. Amorphous material can be detected in samples as shown in FIG. 16 , as part of a mixture of amorphous and polymorphic materials.
Polymorphic Materials
The polymorphic forms of compound A were prepared using material that was produced as described in steps 1 through 9. Seed crystal was obtained from lab scale preparations spontaneously or upon chromatographic purification. An X Ray Powder Diffraction Pattern of a mixture of amorphous and polymorphic forms is included for comparison purposes as FIG. 16 .
X-ray powder diffraction (XRPD) patterns for the solid phases of compound A were generated on a Philips Analytical X'Pert PRO X-ray Diffraction System with PW3040/60 console. The diffraction peak positions were referenced by silicon which has a 2 theta value of 28.443 degree. A PW3373/00 ceramic Cu LEF X-ray tube K-Alpha radiation was used as the source. The experiments were run at ambient condition except for the anhydrate of polymorphic form I, where the measurement was carried out at 5% relative humidity at room temperature.
Solid-state carbon-13 NMR spectra were obtained on a Bruker DSX 400WB NMR system using a Bruker 4 mm double resonance CPMAS probe. The carbon-13 NMR spectrum utilized proton/carbon-13 cross-polarization magic-angle spinning with variable-amplitude cross polarization. The sample was spun at 8 kHz. Chemical shifts are reported on the TMS scale using the carbonyl carbon of glycine (176.03 p.p.m.) as a secondary reference.
Solid-state fluorine-19 NMR spectra were obtained on a Bruker DSX 500WB NMR system using a Bruker 4 mm CRAMPS probe. The NMR spectrum utilized proton/fluorine-19 cross-polarization magic-angle spinning with variable-amplitude cross polarization. The samples were spun at 15.0 kHz. A vespel endcap was utilized to minimize fluorine background. Chemical shifts are reported using poly(tetrafluoroethylene) (Teflon) as an external secondary reference which was assigned a chemical shift of −122 ppm.
Differential Scanning Calorimetry
TA Instruments DSC 2910 or equivalent instrumentation is used to conduct differential scanning calorimetry. Between 1 and 5 mg of a sample is weighed into a sample pan and placed at the sample position in the calorimeter cell. An empty pan is placed at the reference position (either the sample and reference pans are closed or both are open). The calorimeter cell is closed and a flow of nitrogen is passed through the cell. The heating program is set to heat the sample at a heating rate of 10° C./min to a temperature of ˜300° C. The heating program is started. At the completion of the run, the data are analyzed using the Universal analysis program contained in the system software. Integration of any endotherms present is carried out between points on the baseline at temperatures above and below the range in which the endothermic event(s) are observed. Reported data include observed onset temperature, peak temperature, and associated enthalpy of melting.
Thermogravimetric Analysis (TG):
An instrument such as Perkin Elmer model TGA 7 or equivalent is used to conduct thermogravimetric analysis. Experiments are performed under a flow of nitrogen at a heating rate of 10° C./min, and samples are heated to a temperature of about 300° C. To start an experiment, the balance is tared, approximately 3 to 20 mg of sample is added to the platinum pan, the furnace is raised, the sample is weighed, and the heating program is started. Weight/temperature data are collected automatically by the instrument and can be converted to weight percent/temperature. Analysis of the results is carried out by selecting the Delta Y function within the instrument software and the weight loss up to the completion of melting is reported.
Hydrate
The hydrate was produced in accordance with the process set forth above. The term hydrate refers to different crystalline forms of the compound, such as the monohydrate, dihydrate, hemi-hydrate, and the like.
Hydrate: 1 H NMR (400 MHz, CDCl 3 ) δ 8.20 (br s, NH), 7.46 (d, J=8.1 Hz, 2H), 7.28 (d, J=8.5 Hz, 2H), 7.25 (d, J=8.5 Hz, 2H), 7.17 (d, J=8.1 Hz, 2H), 6.94 (s, 1H), 6.83 (d, J=2.1 Hz, 1H), 6.72 (t, J=6.0 Hz, —CONH), 6.60 (d, J=11.9 Hz, 1H), 4.37 (d, J=10.7 Hz, 1H), 3.58 (m, 2H), 3.37 (dt, J=10.7, 3.2 Hz, 1H), 2.57 (m, 2H), 2.35 (s, 3H), 1.50 (m, 1H), 1.40 (m, 1H), 0.98 (m, 2H), 0.71 (t, J=7.3 Hz, 3H).
13 C NMR (100 MHz, CDCl 3 ) δ 176.6, 168.2, 149.2 (d, J CF =243.8 Hz), 149.0, 142.6, 132.1, 131.7, 130.9 (d, J CF =5.5 Hz), 130.0, 129.6 (d, J CF =5.6 Hz), 128.8, 128.5, 127.1, 122.8, 122.6 (d, J CF =13.3 Hz), 118.6 (d, J CF =1.2 Hz), 114.3 (d, J CF =2.5 Hz), 108.6 (d, J CF =15.7 Hz), 50.3, 48.2, 37.3, 35.5, 34.0, 21.8, 20.5, 14.1.
19 F NMR (376 MHz, CDCl 3 ) δ −136.3.
Anal. Calcd for C 30 H 31 ClFN 2 O 35 : C, 67.98; H, 5.90; Cl, 6.69; F, 3.58; N, 5.29. Found: C, 68.11; H, 5.84; Cl, 6.70; F, 3.54; N, 5.33.
Zorbax Eclipse XDB-C8, 4.6×150 mm; A: 0.1% H 3 PO 4 aqueous; B: acetonitrile; 70% to 95% B over 15 min, hold 2 min, post time 4 min. 1.0 mL/min, 10 μL, 210 nm, 30° C. column temperature; desired, RT=3.65 min.
Chiral SFC LC: Chiralpak AD-H column (250×4 6 mm), isocratic 15% MeOH with 25 mM isobutylamine/CO2, 1.5 mL/min, 200 bar, 35° C., 210 nm, 30 min run time: Desired, RT=18.9 min; enantiomer of desired, RT=15.7 min.
Hydrate/Methanolate
One aspect of the invention that is of interest relates to a crystalline polymorphic compound of formula A in the form of a free acid hydrate/methanolate solvate.
The hydrate/methanolate solvate of compound A was obtained by direct crystallization of compound A in methanol/water at different solvent compositions.
Alternatively, it can be obtained by adding excess amount of compound A in methanol/water, stirring for several hours, and recovering the solids by filtration. Characterization is in accordance with Table 1 below.
TABLE 1 X-ray powder diffraction: free acid hydrate/ methanolate of Compound A 2θ(2 theta)(degrees) d-spacing (Å) 7.5 11.74 8.8 10.10 11.3 7.84 13.7 6.44 14.9 5.95 15.4 5.74 17.6 5.05 18.4 4.83 20.3 4.37 21.3 4.17 23.4 3.81 25.6 3.48
Hydrate
An aspect of the invention that is of interest relates to a crystalline polymorphic form of a compound of formula A in the form of a free acid hydrate.
The hydrate of compound A was obtained by removing methanol from the hydrate/methanolate. This can be achieved by drying the hydrate/methanolate at 40° C. at >60% relative humidity. The hydrate can also be converted from the anhydrate of polymorphic form I of compound A by exposing the anhydrate to an atmosphere of >20% relative humidity at room temperature. X Ray characterization is as in Table 2 below.
FIG. 1 is the X-ray powder diffraction (XRPD) pattern for the free acid hydrate polymorphic Form I of Compound A; with selected d-spacings listed in Table 2 below. The compound of formula A exhibits at least three of the d-spacings shown in Table 2, and preferably more than three.
TABLE 2
XRPD: free acid hydrate polymorphic Form I of Compound A
2θ(2 theta)(degrees)
d-spacing (Å)
7.5
11.74
8.8
10.10
11.3
7.84
13.7
6.44
14.9
5.95
15.4
5.74
17.6
5.05
18.4
4.83
20.3
4.37
21.3
4.17
23.4
3.81
25.6
3.48
FIG. 2 is the solid-state fluorine-19 CPMAS NMR spectrum of the free acid hydrate polymorphic Form I of Compound A. Form I exhibited characteristic signals with chemical shift values of −132.7 and −134.3 ppm.
FIG. 3 is the solid-state carbon-13 CPMAS NMR spectrum of the free acid hydrate polymorphic Form I of Compound A. Form I exhibited characteristic signals with chemical shift values of 11.3, 20.2, 23.9, 33.1, 45.5, 108.6, 118.7, 131.7, 139.3, 148.5, 170.1 and 179.9 ppm.
Another aspect of the invention that is of interest relates to the crystalline free acid hydrate of a compound of formula A wherein at least three of the X-ray powder diffraction pattern d-spacings are as found in Table 2.
Another aspect of the invention that is of interest relates to the crystalline free acid hydrate of a compound of formula A wherein at least five of the X-ray powder diffraction pattern d-spacings are as found in Table 2.
Another aspect of the invention that is of interest relates to the crystalline free acid hydrate of a compound of formula A wherein at least three C13 solid state NMR characteristic signals with chemical shift values are selected from the group consisting of: 11.3, 20.2, 23.9, 33.1, 45.5, 108.6, 118.7, 131.7, 139.3, 148.5, 170.1 and 179.9 ppm.
Anhydrate Form I:
Another aspect of the invention that is of interest relates to a crystalline polymorphic compound of formula A in the form of an anhydrous free acid.
More particularly, an aspect of the invention that is of interest relates to a crystalline polymorphic compound of formula A in the form of an anhydrous free acid, said polymorphic compound having at least three X-ray powder diffraction pattern d spacings in accordance with Table 3.
Even more particularly, an aspect of the invention that is of interest relates to a crystalline polymorphic compound of formula A in the form of an anhydrous free acid, said polymorphic compound having at least five X-ray powder diffraction pattern d spacings in accordance with Table 3.
Another aspect of the invention relates to a crystalline polymorphic compound of formula A in the form of an anhydrous free acid, said polymorphic compound having a 19F solid state NMR as shown in FIG. 5 .
The anhydrate I of compound A was obtained either from hydrate/methanolate of compound A by removing methanol/water or from hydrate of compound A by removing water. This can be achieved by drying the hydrate/methanolate or the hydrate with N 2 at room temperature or at higher temperatures. Anhydrate form I of Compound A exhibits at least three of the d-spacings shown in Table 3, and preferably more than three. The solid state 19F NMR characterization for anhydrous free acid polymorphic form I of Compound A exhibited characteristic signals with chemical shift values of −134.8 and −136.3 ppm.
TABLE 3 X-ray powder diffraction: anhydrous free acid polymorphic Form I of Compound A 2θ(2 theta)(degrees) d-spacing (Å) 7.8 11.35 8.7 10.19 9.7 9.11 11.3 7.82 11.9 7.41 14.9 5.93 15.7 5.63 17.4 5.10 20.1 4.41 21.7 4.10 25.6 3.47
Anhydrate Form II:
Another aspect of the invention that is of interest relates to a crystalline polymorphic compound in accordance with formula A in the form of a free acid anhydrate of form II.
In particular, an aspect of the invention that is of interest relates to a crystalline polymorphic compound in accordance with formula A in the form of a free acid anhydrate of form II, wherein at least three of the x-ray powder diffraction pattern d-spacing peaks are in accordance with table 4.
Even more particularly, an aspect of the invention that is of interest relates to a crystalline polymorphic compound in accordance with formula A in the form of a free acid anhydrate of form II, wherein at least five of the x-ray powder diffraction pattern d-spacing peaks are in accordance with table 4.
Anhydrate Form II is prepared from a solution of the crystalline hydrate form at a concentration of >100 mg/mL in acetonitrile. The solution is sonicated for approximately 5 minutes to induce crystallization. Anhydrate II is metastable. It converts to crystalline Anhydrate III when heated to 160° C. for 1 hour or in solutions of ethanol, isoamyl alcohol and isopropyl acetate. The X Ray Powder Diffraction peaks are shown below in Table 4. Anhydrate form II of compound A exhibits at least 3 of the peaks shown below in table 4, and preferably more than four.
TABLE 4
X-Ray Powder Diffraction peaks for Anhydrate Form II
d-spacing [Å]
2θ(2 theta)(degrees)
3.59
24.82
4.05
21.95
4.10
21.70
4.53
19.58
4.72
18.79
5.93
14.93
7.02
12.62
7.31
12.11
8.07
10.96
12.36
7.15
The thermogravimetric analysis curve for crystalline anhydrate form II is shown in FIG. 7 .
The differential scanning calorimetry (DSC) curve of the crystalline anhydrate Form II of Compound I of the present invention is shown in FIG. 8 .
Another aspect of the invention that is of interest relates to a crystalline polymorphic compound of formula A of Form II, having at least three C13 solid state NMR peaks selected from the group consisting of: 131.51, 130.07, 127.68, 126.30, 123.81, 121.65, 52.57, 39.62, 31.77, and 20.79 ppm,
The 13 CPMAS NMR spectrum for the crystalline anhydrate Form II of Compound A is shown in FIG. 9 . Characteristic peaks for anhydrate Form II are observed at 131.51, 130.07, 127.68, 126.30, 123.81, 121.65, 52.57, 39.62, 31.77, and 20.79 ppm.
FIG. 10 shows the fluorine-19 spectra (spinning sideband patterns) for anhydrate Form II of compound I. Center band peaks for anhydrate Form II are observed at −134.80 and −137.08 ppm.
Anhydrate Form III
Another aspect of the invention that is of interest relates to a crystalline polymorphic compound in accordance with formula A in the form of a free acid anhydrate of form III.
In particular, an aspect of the invention that is of interest relates to a crystalline polymorphic compound in accordance with formula A in the form of a free acid anhydrate of form III, wherein at least three of the x-ray powder diffraction pattern d-spacing peaks are in accordance with table 5.
Even more particularly, an aspect of the invention that is of interest relates to a crystalline polymorphic compound in accordance with formula A in the form of a free acid anhydrate of form III, wherein at least five of the x-ray powder diffraction pattern d-spacing peaks are in accordance with table 5.
Anhydrate Form III is prepared by heating anhydrate form II to 160° C. for 1 h. It can also be prepared by slurrying the hydrate or the Anhydrate II in ethanol, isoamyl alcohol and isopropyl acetate.
X-Ray Powder Diffraction for Anhydrate Form III
FIG. 11 is a characteristic X-ray diffraction pattern of the crystalline anhydrate Form III of Compound I of the present invention.
The anhydrate Form III exhibited characteristic reflections corresponding to d-spacings are shown below in Table 5. Anhydrate form III of compound A exhibits at least three of the d-spacings shown in table 5, and preferably more than three.
TABLE 5 2 theta d-spacing [Å] 26.42 3.37 24.90 3.58 24.61 3.62 23.87 3.73 23.21 3.83 22.44 3.96 19.66 4.52 19.43 4.57 17.94 4.94 12.2927 7.20
Thermogravimetric Analysis for Anhydrate Form III
FIG. 12 is a typical thermogravimetric analysis curve of the crystalline anhydrate Form III of Compound A.
Differential Scanning Calorimetry
FIG. 13 is a typical differential scanning calorimetry (DSC) curve of the crystalline anhydrate Form III of Compound A.
Solid State NMR
Another aspect of the invention that is of interest relates to a crystalline polymorphic compound of formula A of Form III, having at least three C13 solid state NMR peaks selected from the group consisting of: 177.58, 148.52, 146.17, 130.34, 121.11, 113.44, 52.77, 31.30, 21.42, and 14.04 ppm.
FIG. 14 shows the solid state carbon-13 CPMAS NMR spectrum for the crystalline anhydrate Form III of Compound A.
Anhydrate III can be characterized by peaks at 177.58, 148.52, 146.17, 130.34, 121.11, 113.44, 52.77, 31.30, 21.42, and 14.04 ppm.
FIG. 15 shows the fluorine-19 spectra (spinning sideband patterns) of crystalline Anhydrate III of Compound A. Anhydrate form III exhibits center band signals at −132.96 and −136.45 ppm.
Another aspect of the invention that is of interest relates to a pharmaceutical composition that is comprised of a polymorphic form of a compound of formula A in combination with a pharmaceutically acceptable carrier.
The following are examples of pharmaceutical dosage forms containing a compound of Formula A:
Injectable
Mg/
Suspension (im.)
mg/mL
Tablet
tablet
Compound of Formula A
10.0
Compound of Formula A
25.0
Methylcellulose
5.0
Microcrystalline Cellulose
415
Tween 80
0.5
Povidone
14.0
Benzyl alcohol
9.0
Pregelatinized Starch
4.35
Benzalkonium chloride
1.0
Magnesium Stearate
2.5
Water for injection
t.d.
Total
500 mg
1.0 mL
mg/
Per
Capsule
capsule
Aerosol
Canister
Compound of Formula A
25.0
Compound of Formula A
250 mg
Lactose
735
Lecithin, NF Liq. Conc.
1.2 mg
Mg Stearate
1.5
Trichloromethane, NF
4.025 g
Total
600 mg
Dichlorodifluoromethane,
12.15 g
NF
Certain embodiments of the invention has been described in detail; however, numerous other embodiments are contemplated as falling within the invention. Thus, the claims are not limited to the specific embodiments described herein. All patents, patent applications and publications that are cited herein are hereby incorporated by reference in their entirety.
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The present invention relates to polymorphic forms of a compound of formula A:
This compound is useful as a glucagon receptor antagonist and serves as a pharmaceutically active ingredient for the treatment of type 2 diabetes and related conditions, such as hyperglycemia, obesity, dyslipidemia, and the metabolic syndrome. Hydrates, hemihydrates, anhydrates and similar polymorphic forms are included.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to cardiac catheterization. More particularly, this invention relates to improvements in detecting complications of cardiac catheterization.
[0003] 2. Description of the Related Art
[0004] The meanings of certain acronyms and abbreviations used herein are given in Table 1.
[0000]
TABLE 1
Acronyms and Abbreviations
MRI
Magnetic Resonance Imaging
ECG
Electrocardiogram
[0005] Cardiac arrhythmias, such as atrial fibrillation, occur when regions of cardiac tissue abnormally conduct electric signals to adjacent tissue, thereby disrupting the normal cardiac cycle and causing asynchronous rhythm.
[0006] Procedures for treating such arrhythmias include surgically disrupting the origin of the signals causing the arrhythmia, as well as disrupting the conducting pathway for such signals. By selectively ablating cardiac tissue by application of energy via a catheter, it is sometimes possible to interrupt or modify the propagation of unwanted electrical signals from one portion of the heart to another. The ablation process destroys the unwanted electrical pathways by formation of non-conducting lesions.
[0007] Verification of physical electrode contact with the target tissue is important for controlling the delivery of ablation energy while avoiding excessive contact force that might cause damage to the cardiac tissues. Attempts in the art to verify electrode contact with the tissue have been extensive, and various techniques have been suggested. For example, U.S. Pat. No. 6,695,808 describes apparatus for treating a selected patient tissue or organ region. A probe has a contact surface that may be urged against the region, thereby creating contact pressure. A pressure transducer measures the contact pressure. This arrangement is said to meet the needs of procedures in which a medical instrument must be placed in firm but not excessive contact with an anatomical surface, by providing information to the user of the instrument that is indicative of the existence and magnitude of the contact force.
[0008] In an invasive procedure performed on the heart, particularly a procedure involving mapping and ablation, there is a concern that the myocardial wall may be perforated, leading to unwanted entry of blood into the pericardial sac (hemopericardium) and development of a life threatening cardiac tamponade. Such a perforation is typically small. However, the flow rate of blood from the ventricular or atrial chamber into the pericardial space varies from low to high. Accordingly, it may take from a few minutes to a number of hours before the existence of the perforation is apparent.
[0009] A detailed description of the pericardial anatomy is given in the document Cardiac MRI: Part 2 , Pericardial Diseases , Prabhakar Rajiah, American Journal of Roentgenology. October 2011; Vol. 197:W621-W634 (Rajiah), which is herein incorporated by reference. As is explained in Rajiah, the so-called “black blood” magnetic resonance imaging (MRI) technique may include weighted T1 and T2 sequences. The technique is useful to visualize normal pericardial anatomy, as well as effusions of blood into the pericardial sac. The black blood technique is a spin-echo MRI mode, in which high-velocity signal loss occurs. The technique employs excitation and refocusing pulses, which are 90° out of phase. Blood flowing within the heart in a slice of interest at the time of the 180° pulse will not have received the 90° pulse. Therefore, there is no magnetization in the transverse plane of the slice to refocus to an echo, and only a dark area appears on the resulting image. Pericardial fluid, which is not in rapid motion, appears as a white band on the image.
SUMMARY OF THE INVENTION
[0010] Embodiments of the present invention operate the black blood MRI protocol as a computer process in order to detect real-time perforation of the myocardial wall during an ongoing cardiac catheterization procedure. Typically, MRI and ablation are performed concurrently using a combined, MRI and CARTO electroanatomical mapping system, or suite. In order to detect perforation, an image-processing program is operated periodically in background on black blood imaging data. The computer processor runs an automatic image-processing algorithm that compares successive images in order to detect changes in the anatomy of the pericardium. The images may be analyzed by the processor without the images being actually displayed. Alternatively or additionally, the processor may run the black blood protocol in background when perforation is suspected, for example, after a specific predefined contact force was exceeded during catheter manipulation, mapping or an ablation.
[0011] In some embodiments the processor is configured to check specific susceptible regions of the pericardium, where there is an expectation that blood is most likely to start accumulating.
[0012] The black blood protocol as described herein allows nearly instantaneous intraoperative detection of perforation of the epicardium. Its automatic mode of operation is transparent to the operator, and does not interfere with the ongoing catheterization procedure unless an abnormal event is detected.
[0013] There is provided according to embodiments of the invention a method, which is carried out by inserting a probe into a heart of a living subject, navigating the probe into a contacting relationship with a target tissue of the heart, and performing a medical procedure on the target. The method is further carried out during the medical procedure by iteratively acquiring magnetic resonance imaging (MRI) data that includes the pericardium, including a first set of MRI data and a second set of MRI data, measuring the pericardium by analyzing the sets of MRI data, making a determination that a measurement of the pericardium in the second set of MRI data differs from the measurement of the pericardium in the first set of MRI data, and responsively to the determination reporting a change in configuration of the pericardium.
[0014] According to an aspect of the method, acquiring the MRI data comprises black blood imaging of the pericardium.
[0015] According to still another aspect of the method, measuring the pericardium comprises detecting a separation of the visceral layer from the parietal layer of the pericardium.
[0016] According to another aspect of the method, making the determination comprises failing to detect the separation on the first set of MRI data and detecting the separation on the second set of MRI data.
[0017] According to one aspect of the method, making the determination comprises detecting a change in a distance between the visceral layer and the parietal layer that exceeds a predetermined value, which can be 0.1 mm.
[0018] According to still another aspect of the method, the separation is detected in a superior recess of the pericardium, adjacent to a posterolateral wall of the heart or adjacent to an inferolateral right ventricular wall of the heart.
[0019] According to yet another aspect of the method, iteratively acquiring is performed at intervals of between 5 sec and 3 minutes.
[0020] There is further provided according to embodiments of the invention a medical apparatus, including a probe, adapted for insertion into a heart, a memory having programs stored therein, a display, and a processor linked to the display and coupled to access the memory to execute the programs. The processor is connectable to a MRI apparatus. The programs include a MRI control module and an image analysis module, wherein the programs cause the processor to perform the steps of iteratively acquiring magnetic resonance imaging (MRI) data that includes the pericardium by invoking the MRI control module to communicate control signals to the MRI apparatus. The MRI data includes a first set of MRI data and a second set of MRI data. The processor is operative for measuring the pericardium by analyzing the sets of MRI data using the image analysis module, making a determination that a measurement of the pericardium in the second set of MRI data differs from the measurement of the pericardium in the first set of MRI data, and responsively to the determination reporting a change in configuration of the pericardium, wherein iteratively acquiring, measuring, making a determination, and reporting are performed while performing a medical procedure on a living subject.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0021] For a better understanding of the present invention, reference is made to the detailed description of the invention, by way of example, which is to be read in conjunction with the following drawings, wherein like elements are given like reference numerals, and wherein:
[0022] FIG. 1 is a pictorial illustration of a system for performing catheterization procedures on a heart, in accordance with a disclosed embodiment of the invention;
[0023] FIG. 2 shows MRI images illustrating discovery of pericardial fluid in accordance with an embodiment of the invention;
[0024] FIG. 3 is a pictorial block diagram of an embodiment of the system shown in FIG. 1 , in accordance with an embodiment of the invention;
[0025] FIG. 4 is a flow-chart of a method of evaluating the pericardium during cardiac catheterization, in accordance with an embodiment of the invention;
[0026] FIG. 5 is a detailed flow-chart illustrating details of the method shown in FIG. 4 , in accordance with an embodiment of the invention; and
[0027] FIG. 6 is a detailed flow chart of a method of automatic detection of hemopericardium, in accordance with an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0028] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the various principles of the present invention. It will be apparent to one skilled in the art, however, that not all these details are necessarily always needed for practicing the present invention. In this instance, well-known circuits, control logic, and the details of computer program instructions for conventional algorithms and processes have not been shown in detail in order not to obscure the general concepts unnecessarily.
[0029] Aspects of the present invention may be embodied in software programming code, which is typically maintained in permanent storage, such as a computer readable medium. In a client/server environment, such software programming code may be stored on a client or a server. The software programming code may be embodied on any of a variety of known non-transitory media for use with a data processing system, such as USB memory, hard drive, electronic media or CD-ROM. The code may be distributed on such media, or may be distributed to users from the memory or storage of one computer system over a network of some type to storage devices on other computer systems for use by users of such other systems.
[0030] Turning now to the drawings, reference is initially made to FIG. 1 , which is a pictorial illustration of a system 10 for performing catheterization procedures on a heart 12 of a living subject, which is constructed and operative in accordance with a disclosed embodiment of the invention. The system 10 typically comprises a general purpose or embedded computer processor, which is programmed with suitable software for carrying out the functions described hereinbelow. Thus, although portions of the system 10 shown in FIG. 1 and other drawing figures herein are shown as comprising a number of separate functional blocks, these blocks are not necessarily separate physical entities, but rather may represent, for example, different computing tasks or data objects stored in a memory that is accessible to the processor. These tasks may be carried out in software running on a single processor, or on multiple processors. Alternatively or additionally, the system 10 may comprise a digital signal processor or hard-wired logic.
[0031] The system comprises a catheter 14 , which is percutaneously inserted by an operator 16 through the patient's vascular system into a chamber or vascular structure of the heart 12 . The operator 16 , who is typically a physician, brings the catheter's distal tip 18 into contact with the heart wall at an ablation target site. Electrical activation maps, anatomic positional information, i.e., of the distal portion of the catheter, and other functional images may then be prepared using a processor 22 located in a console 24 , according to the methods disclosed in U.S. Pat. Nos. 6,226,542, and 6,301,496, and in commonly assigned U.S. Pat. No. 6,892,091, whose disclosures are herein incorporated by reference. One commercial product embodying elements of the system 10 is available as the CARTO® 3 System, available from Biosense Webster, Inc., 3333 Diamond Canyon Road, Diamond Bar, Calif. 91765, which is capable of producing electroanatomic maps of the heart as required for the ablation. This system may be modified by those skilled in the art to embody the principles of the invention described herein.
[0032] Areas determined to be abnormal, for example by evaluation of the electrical activation maps, can be ablated by application of thermal energy, e.g., by passage of radiofrequency electrical current through wires in the catheter to one or more electrodes at the distal tip 18 , which apply the radiofrequency energy to the myocardium. The energy is absorbed in the tissue, heating (or cooling) it to a point (typically about 50° C.) at which it permanently loses its electrical excitability. When successful, this procedure creates non-conducting lesions in the cardiac tissue, which disrupt the abnormal electrical pathway causing the arrhythmia. The principles of the invention can be applied to different heart chambers to treat many different cardiac arrhythmias.
[0033] The catheter 14 typically comprises a handle 20 , having suitable controls on the handle to enable the operator 16 to steer, position and orient the distal end of the catheter as desired for the ablation. To aid the operator 16 , the distal portion of the catheter 14 contains position sensors (not shown) that provide signals to a positioning processor 22 , located in the console 24 .
[0034] Ablation energy and electrical signals can be conveyed to and from the heart 12 through the catheter tip and/or one or more ablation electrodes 32 located at or near the distal tip 18 via cable 34 to the console 24 . Pacing signals and other control signals may be conveyed from the console 24 through the cable 34 and the electrodes 32 to the heart 12 . Sensing electrodes 33 , also connected to the console 24 are disposed between the ablation electrodes 32 and have connections to the cable 34 .
[0035] Wire connections 35 link the console 24 with body surface electrodes 30 and other components of a positioning sub-system. The electrodes 32 and the body surface electrodes 30 may be used to measure tissue impedance at the ablation site as taught in U.S. Pat. No. 7,536,218, issued to Govari et al., which is herein incorporated by reference. A temperature sensor (not shown), typically a thermocouple or thermistor, may be mounted on or near each of the electrodes 32 .
[0036] The console 24 typically contains one or more ablation power connections. The catheter 14 may be adapted to conduct ablative energy to the heart using any known ablation technique, e.g., radiofrequency energy, ultrasound energy, freezing technique and laser-produced light energy. Such methods are disclosed in commonly assigned U.S. Pat. Nos. 6,814,733, 6,997,924, and 7,156,816, which are herein incorporated by reference.
[0037] The positioning processor 22 is an element of a positioning subsystem in the system 10 that measures location and orientation coordinates of the catheter 14 .
[0038] In one embodiment, the positioning subsystem comprises a magnetic position tracking arrangement that determines the position and orientation of the catheter 14 by generating magnetic fields in a predefined working volume and sensing these fields at the catheter, using field generating coils 28 . The positioning subsystem may employ impedance measurement, as taught, for example in U.S. Pat. No. 7,756,576, which is hereby incorporated by reference, and in the above-noted U.S. Pat. No. 7,536,218.
[0039] A MRI imaging device 37 is linked to a control processor 47 , which may be located in the console 24 . An operator may select or override automatic operation to control the operation of the MRI imaging device 37 , for example by revising imaging parameters. The control processor 47 may communicate with the MRI imaging device 37 via a cable 51 to enable and disable the MRI imaging device 37 to acquire image data. An optional display monitor 49 , linked to the control processor 47 , allows the operator to view images produced by the MRI imaging device 37 . When the display monitor 49 is not included, the images may still be viewed on a monitor 29 , either via a split screen or in alternation with other images.
[0040] As noted above, the catheter 14 is coupled to the console 24 , which enables the operator 16 to observe and regulate the functions of the catheter 14 . The processor 22 is typically a computer with appropriate signal processing circuits. The processor 22 is coupled to drive the monitor 29 . The signal processing circuits typically receive, amplify, filter and digitize signals from the catheter 14 and the MRI imaging device 37 , including signals generated by the above-noted sensors and a plurality of location sensing electrodes (not shown) located distally in the catheter 14 . The digitized signals are received and used by the console 24 and the positioning system to compute the position and orientation of the catheter 14 , analyze the electrical signals from the electrodes and generate desired electroanatomic maps. The above-described arrangement works well when a shared coordinate system is shared between system components, e.g., a combined CARTO-MRI system. This is especially true when ablating the atria, as its wall is very thin, and it is necessary to define its boundaries. Despite advances in image processing, edge detection of the endocardial wall continues to be challenging, and conventionally requires manual analysis of sequential slice images. However, with a trackable, MRI-compatible, indwelling catheter that touches the endocardial wall and measures contact-force, manual analysis can be avoided.
[0041] Typically, the system 10 includes other elements, which are not shown in the figures for the sake of simplicity. For example, the system 10 may include an electrocardiogram (ECG) monitor, coupled to receive signals from one or more body surface electrodes, to provide an ECG synchronization signal to the console 24 . As mentioned above, the system 10 typically also includes a reference position sensor, either on an externally-applied reference patch attached to the exterior of the subject's body, or on an internally placed catheter, which is inserted into the heart 12 maintained in a fixed position relative to the heart 12 . Conventional pumps and lines for circulating liquids through the catheter 14 for cooling the ablation site are provided.
[0042] Reference is now made to FIG. 2 , which shows MRI images illustrating discovery of pericardial fluid in accordance with an embodiment of the invention. At the left side of the figure is a black blood intraoperative MRI frame 53 showing a four-chamber view of a normal heart 55 and pericardium 57 . The distal portion of a cardiac catheter 59 is shown in contact with endocardial surface 61 of the heart 55 . A relatively small amount of fluid in the pericardial space appears as a narrow black band 63 lying between thicker white strips 123 , 125 . The strips 123 , 125 correspond to the parietal and visceral pericardium, which are often inseparable on images of this sort. In FIG. 2 the two pericardial layers can be resolved as a result of a physiologic amount of pericardial fluid.
[0043] At the right of FIG. 2 is a diagram comprising another intraoperative black blood MRI frame 65 with the cardiac catheter 59 superimposed thereon. Blood has accumulated within the pericardium, presumably originating from the cardiac chamber. If the MRI frame 65 were presented visually, as shown in FIG. 1 , the operator would recognize the hemopericardium as an intraoperative complication of the catheterization. Alternatively, the control processor 47 would have acquired successive MRI frames, and would have identified the MRI frame 65 as significantly deviating from previous frames, e.g., the MRI frame 53 . In FIG. 2 , a hemorrhagic pericardial effusion has occurred as a complication of cardiac catheterization. The blood appears on the MRI frame 65 as a region of low signal intensity, indicated by arrows 67 , 69 , 71 , 73 . Typically, the earliest collection of pericardial fluid occurs adjacent to the posterolateral left ventricular wall or the inferolateral right ventricular wall, after which pericardial fluid accumulates in the superior recess.
[0044] Reference is now made to FIG. 3 , which is a pictorial block diagram of an embodiment of the system 10 ( FIG. 1 ) for detecting perforation of the epicardium during cardiac catheterization using magnetic resonance imaging, in accordance with an embodiment of the invention. A control processor 75 communicates with catheter 14 while it is in the heart 12 via cable 51 and deals with routine aspects of a medical procedure involving the catheter 14 , using any of a position tracking position tracking module 77 , an ablation generator 79 and a mapping module 81 . MRI acquisition unit 83 may be activated from time to time by the operator to acquire and prepare MRI images using the facilities of an image processor 85 and a display 87 to assist the operator in visualizing the cardiac anatomy and optionally visualizing the distal portion of the catheter 14 in embodiments in which sensing elements appropriate to MRI techniques are included with the catheter 14 . In addition, a MRI control program 89 executing in the control processor 75 transmits control signals to the MRI acquisition unit 83 causing MRI images to be acquired by the MRI acquisition unit 83 according to a predefined schedule or responsively to calculations of an image analysis module 91 , which operates on data obtained from the image processor 85 . The image processor 85 may be provided in the MRI acquisition unit 83 , or may be integral with the control processor 75 , or be a separate entity as shown in FIG. 3 . As is explained in further detail below, the image analysis module 91 is programmed to detect an increase in the volume of the pericardial space during the course of the catheterization, and when conditions are met, to alert the operator by a notification on the display 87 , audibly via a speaker 93 , or both.
[0045] Reference is now made to FIG. 4 , which is a flow-chart of a method of evaluating the pericardium during cardiac catheterization, in accordance with an embodiment of the invention. At initial step 95 , a cardiac catheter is introduced into a subject and navigated to a target, typically within a chamber of the heart. This may be accomplished using the facilities of the above-mentioned CARTO system, optionally aided by an imaging modality, e.g., MRI.
[0046] Next, at an optional step 97 , contact between the catheter and the target is verified and the contact force adjusted if necessary. Contact force determination can be accomplished using the teachings of application Ser. No. 13/589,347, entitled “Machine Learning in Determining Catheter Electrode Contact” and U.S. Patent Application Publication No. 2013/0172875, entitled “Contact Assessment Based on Phase Measurement”, both of which are commonly assigned and are herein incorporated by reference.
[0047] At step 99 , a medical operation is carried out by the operator, e.g., mapping or ablation at an area of interest.
[0048] During the performance of steps 97 , 99 an iterative procedure involving MRI is carried out:
[0049] An MRI image of the field of interest is acquired at step 101 , and analyzed to evaluate the configuration of the pericardial space. The first iteration of step 101 constitutes a reference against which image data from subsequent iterations are compared.
[0050] Next, at decision step 103 , it is determined if analysis of the image data shows increased separation between the parietal and visceral pericardium in at least a portion of the pericardial space, indicating the formation of a hemopericardium. Width of the pericardial sac is an exemplary indication of the volume of the pericardial sac, and hence its liquid content. Other indicators of pericardial volume that can be determined on MRI images will occur to those skilled in the art. In some embodiments, the analysis may be accomplished with the aid of a conventional image processing program provided by the manufacturer of the MRI imaging device, optionally supplemented by the image analysis module 91 ( FIG. 3 ). Alternatively, the image analysis module 91 may be programmed to evaluate raw or partially processed image data so as to recognize any intraoperative change in the pericardial anatomy, for example, in a comparison of the parietal and visceral pericardial layers in the two images in FIG. 2 . One set of images is compared with a baseline set or a previous performance of decision step 103 . In any case, the evaluation of the image data is performed automatically, and may be executed as a background process by the control processor 75 ( FIG. 3 ). If the determination at decision step 103 is negative, then after a predetermined delay interval control returns to step 101 for acquisition of new image data.
[0051] If the determination at decision step 103 is affirmative then control proceeds to step 105 . An alert to the operator is issued.
[0052] Final step 107 is performed upon completion of step 99 or step 105 , whichever occurs first. The procedure accordingly terminates normally or abnormally.
[0053] Reference is now made to FIG. 5 , which is a flow-chart illustrating details of decision step 103 ( FIG. 4 ), in accordance with an embodiment of the invention. Normal pericardial thickness ranges from 1.2 to 1.7 mm on MRI images. When fluid accumulates in the pericardium quickly, pericardial pressures can increase substantially and produce well-known hemodynamic effects. One method of automatically evaluating MRI image data of the heart and pericardium in successive iterations of decision step 103 ( FIG. 4 ) exploits information known from the above-noted Rajiah document: pericardial fluid does not necessarily spread homogeneously. Rather, the earliest collection of pericardial fluid occurs adjacent to the posterolateral left ventricular wall or the inferolateral right ventricle wall, after which pericardial fluid accumulates in the superior recess. Moderate-sized collections of fluid (100-500 mL) tend to accumulate in the anterior aspect of the right ventricle as well. Large effusions are seen anterior to the right atrium and right ventricle.
[0054] At initial step 109 , a baseline or scout MRI image of the heart and pericardium is obtained. This may be conveniently done at the beginning of the catheterization session, or may be a previously obtained image. The images described in this method are obtained using the above-noted black blood technique.
[0055] Next, at step 111 the following target areas are identified: the posterolateral left ventricular wall, the inferolateral right ventricle wall, and the superior recess.
[0056] Next, at step 113 , MRI images are acquired to include at least the target areas that were identified in step 111 . In some embodiments, the images are selected or acquired to synchronize with cardiorespiratory motions. Measurements of the distances between the visceral and parietal pericardium are recorded at the target areas. This may be accomplished using routines provided by the image analysis module 91 ( FIG. 3 ). The measurements may include defining spatial regions of interest for the posterolateral left ventricular wall, and the inferolateral right ventricular wall, and analyzing the data in the regions of interest, respectively.
[0057] Next, at decision step 115 , it is determined if the measurements obtained in step 113 vary from a previous iteration (or the scout image) by more than a predetermined value. A suitable threshold of variation for this purpose depends upon the strength of the MRI magnetic field and is 0.1-0.3 mm for 3 T and 1.5 T, respectively. It will be recalled from the discussion above that normally almost no separation is evident between the parietal and visceral and visceral layers of the pericardium on black blood MRI images. However, in some patients, there is a very small physiological pericardial effusion, which represents a normal anatomical variant. Appearance of any discernable separation on a new iteration of step 113 when it was not detectable on a previous iteration may be a significant change in the images.
[0058] If the determination is affirmative, then an alert is reported at step 117 . Otherwise, a negative report is communicated at step 119 .
[0059] After performing either of steps 117 , 119 , delay step 121 is performed. The delay interval is not critical, but should be small enough to detect significant changes in the pericardium before hemodynamic changes occur. A delay interval of 5 seconds is suitable. However, longer delay intervals may be tolerated, and the intervals may vary in different phases of the medical procedure. For example during ablation, the intervals may be shortened, while during mapping longer intervals may be chosen. Thereafter, a new iteration begins at step 113 .
[0060] Reference is now made to FIG. 6 , which is a detailed flow chart of a method of automatic detection of hemopericardium, in accordance with an embodiment of the invention. The steps shown in FIG. 6 are discussed with reference to the following pseudocode, and represent computer-implemented functions.
[0061] Step 127 : V]=Perform — 3D_Anatomy_Scan(x0,y0,z0, size_X,size_Y,size_Z,O). This function receives coordinates, orientation and image size and performs a 3D volumetric scan. The scan can be rendered also as a 2D scan.
[0062] Step 129 [M]=Perform_Magnetic_Mapping_with_tagging_possible_perforation_regions (x,y,z,is_dangerous). This function receives coordinates, and a Boolean parameter if the current region is dangerous or not and returns a value M, which is binary 3D mask of 1 for dangerous pixels and 0 otherwise.
[0063] Tagging can be manually pre-defined or performed in real time according to the following criteria:
[0064] Mode==1: Pre-defined manually
[0065] Mode==2: if current_tissue_thickness>former_tissue_thickness
[0066] Mode==3: Contact_Force_value>threshold_CF
[0067] Mode==4: Blood_Pressure<threshold_BP
[0068] Mode==5: Is_Abnormal_Ablation_Parameter_exist
[0069] Step 131 [L,O]=Get_Location (B1,B2,B3). This function returns catheter position and orientation relative to MRI system of coordinates according to a magnetic field B received from the location pad.
[0070] Decision step 133 [is_true]=Is_potential_perforation_region(L,O,M). This function receives a mask (3D volumetric binary data of the mapping and anatomy) and returns Boolean value whether the current location is potential perforation region or not. If the Boolean value is false, step 131 is performed.
[0071] If the Boolean value in decision step 133 is true, then step 135 is performed: [Data]=Bring_MRI_volumetric_data(L,O). This function scans quickly a very small region defined by location and orientation via black blood sequence and returns the grey level data.
[0072] If conditions are appropriate as noted above, a new 3D scan is performed at step 137
[0073] Step 139 represents analysis of the data thus far obtained, and is performed by a group of functions:
[0074] [Is_perforated=Analyze(mode) This function receives a mode, which defines which of several analysis types will be applied:
[0075] If mode==1 then call Analyze_via_Image_Algebra
[0076] Else if mode==2 call Analyze_via_gradient_analysis
[0077] Else call Analyze_via_tissue thickness.
[0078] Decision step 141 can be performed by invoking one or more of the following functions:
[0079] [is_peforated]=Analyze_via_Image_Algebra(Initial,Current).] The ImageAlgebra tool provided by Philips may be used for this function. This function receives an initial volumetric data (from Perform — 3D_Anatomy_Scan) as well as current data (from step 135 ), normalize it by:
[0080] Initial=Initial/mean(Initial)
[0081] Current=Current/mean(Current)
[0082] Apply Image algebra: deviation=abs(Initial-Current)
[0083] Max_deviation=max(deviation)
[0084] If Max_deviation>threshold->alert.
[0085] [is_peforated]=Analyze_via_gradient_analysis(Initial,Current,L,O). Trace a ray from current catheter location, which is in contact with current catheter orientation and derivate the gray level. If there are global minima in the middle, then there is perforation because pericardial sac as well as tissue will provide constant gradient change. But if there is blood (which is black) between the sac and tissue there will be a local minimum (according to Fermat's Law).
[0086] [is_peforated]=Analyze_via_tissue thickness (Initial,Current,L,O)
[0087] If current_tissue_thickness-initial_tissue_thickness>threshold_TS then is_peforated==true.
[0088] Steps 143 , 145 concern alerting the operator and taking corrective action, respectively, when a possible or actual perforation is detected at decision step 141 . In step 145 , the function Apply_Safety_Procedure(is_preforated) disconnects ablation option and may apply lifesaving procedures, which are outside the scope of this disclosure.
[0089] If no blood is detected in the pericardial sac at decision step 141 , then data is updated and stored at step 147 . The algorithm then iterates at step 131 .
[0090] It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and sub-combinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description.
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Cardiac ablation is monitored to detect hemopericardium by iteratively acquiring magnetic resonance imaging (MRI) data that includes the pericardium, measuring the pericardium by analyzing the sets of MRI data, making a determination that a measurement of the pericardium in consecutive sets of MRI data differ, and responsively to the determination reporting a change in configuration of the pericardium.
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FIELD OF THE INVENTION
[0001] The present invention relates to vehicles, and, especially, automotive vehicles in the automotive and/or truck sector, with HVAC distribution systems useful for heating, cooling or drying apparel.
BACKGROUND OF THE INVENTION
[0002] Passengers in automotive vehicles have often experienced the problem of wet or frozen forms of apparel which they have maintained on their person on in the back of vehicles to avoid either wear of such wet and or frozen, uncomfortable pieces of clothing, or to dry out such articles of clothing or other such items prior to repeated use. In fact, though often apparel has been dried and/or warmed via alternative methods (sunlight, outside heat generating devices, other devices outside of the motor vehicle, etc.) there has not been an outpouring of commercially available add on/ vehicular designed equipment for the SUV, truck, or work-mans vehicle, and, particularly no such device built in for pre-warming, drying, or cooling such apparel. Present day solutions to uncomfortable apparel brought upon my moisture, and, in particular, cold or frozen moisture, has been to place or throw apparel in the foot-well region of the vehicle (either front or rear), and leave it there until natural methods over time dried them out. One solution has been to crank up the heat in the vehicle to cause the boot or the cockpit of the vehicle to become super heated, and, thus, drive the moisture out of the apparel. However, this system has the disadvantage that the passenger would often become uncomfortable with the excess heat/cooling from the HVAC system since it the HVAC system has not been designed and has not been targeted and/or efficiently arranged to provide for use of heat/cooling in drying/warming or cooling the from such HVAC system which was not designed to work with such apparel.
SUMMARY OF THE INVENTION
[0003] The present invention relates to a pre-conditioning system based on using HVAC technology designed to target and/or efficiently use the HVAC system to provide for heating, cooling, drying or warming of materials using a specific device as part of the pre-conditioning system of a motor vehicle. Whereas such as system could be conceived to provide for a certain climate control in a specific area for a number of purposes, it is especially useful in providing for a way of treating moisture exposed or ridden materials, such as clothing and other wearing apparel, that have been chilled, heated, wetted or dampened prior to entry into the vehicle.
[0004] In preferred embodiments of the present invention, such a system, with such an incorporated device, could be used, for example, in preparation of ski-outings or work sites while the car or truck or other such motor vehicle is driving to the ski area. During the time it takes to reach the skill area, the present invention may be used to pre-condition, such as warm a variety of materials, and, in particular, clothing or other apparel, such as ski-boots, snow boots, walking shoes, working shoes and/or boots. In other preferred embodiments of the present invention, the pre-conditioning system, with its specific incorporated device, could be used to pre-condition or dry out clothing or apparel or the like so that the clothing or apparel, when moist, damp, wet from perspiration or exterior sources, that often are found with the general sporting activities, such as gloves, hats, clothes and leg and body garments (children's snow-suits, hats, gloves, scarves) are also envisoned. Other types of materials, such as water skiing equipment with suitable catch trays, etc., could be dried out or made more comfortable using the present invention. In more preferred embodiments of the present invention, the HVAC pre-conditioning system is arranged to enable both storage and pre-conditioning of material, equipment and apparel, in a neat and organized fashion in the rear of the vehicle.
[0005] The present invention can utilize air that goes through the HVAC unit after conditioning (conditioning air). In preferred embodiments of the present invention, the HVAC unit may be part of a front unit or a back (rear) unit. In more preferred embodiments, for reason of reduction in complexity, use of less materials, and to allow unused or available space in the back to be utilized, a rear HVAC unit can be used as part of the pre-conditioning system. Of course, although the cool air part of the rear HVAC unit provides for preferred results for many uses, due to its outputted air of low humidity and heat, both the cool air path of the rear HVAC (after air has passed by or through the evaporator and become ‘moisture reduced’ or ‘dried’), and the hot air path (after air has passed through or by the heater core and become ‘warmed’), in preferred embodiments, provides for conditioning air to pre-condition (warm and/or dry air heat or dry) apparel in need of pre-conditioning.
[0006] In a preferred method of the present invention, conditioned air, either heated or cooled, or both, passes through the HVAC unit before being distributed into a series of ducts to perform a pre-conditioning for material or apparel in the motor vehicle. Preferred embodiments of the present invention would, therefore, prove useful for work people, sporty people, vacationers, activity trainers and patrons and others to pre condition (dry and warm) their apparel. Specifically, persons knowing that they might need ski boots, snowboard boots and gloves, prior to arrival at the slopes/workplace/walking trails, outdoor or indoor humid or cool or hot regions, leisure facilities or like place, where apparel could become moist, damp or wet, could find a system such as disclosed herein, to pre-conditioned such material, equipment or apparel, to be quite useful. In addition, the preferred embodiments of the present invention allow apparel to be further pre-conditioned, i.e. dried and/or warmed after using the apparel on the appropriate activity. Pre-conditioning means that the equipment/material/apparel are in a more ready state for the next use after being pre-conditioned in the motor vehicle, and, particularly, when lack of such pre-conditionment would lead to discomfort while wearing or using the above.
[0007] In preferred embodiments of the present invention, the invention presents a major advantage over the prior art in that apparel so conditioned will be in a more suitable state for re-use (from the point of view of workman, skier, snowboarder, activity person, traveler or the like whom has wet, moist or damp apparel) during and after use and prior to use again the next time/session/day. The preferred embodiments of the present invention, by providing pre-condition, also fully or partially eliminate the need for direct drying or warming of material, equipment, and, especially, apparel, in the home, hotel, residence or place of work.
[0008] The present invention envisions numerous types of equipment, materials and apparel that can be pre-conditioned by the pre-conditioning system and by pre-conditioning methods. Non-limiting examples of such equipment, materials and apparel include: apparel such as footwear (walking boots/shoes, sneakers, ski-boots (preferably), snowboard-boots (preferably), work boots, waders, or general or sport or activity like foot attire) and clothing (jackets, tops, sweat-tops, leggings, snow-pants (preferable), snow-suits or accessories (hats, gloves, scarves, face shields, muffs, mittens etc).
[0009] The present invention provides for a pre-conditioning system for pre-conditioning materials, equipment and apparel, preferably materials and apparel, more preferably apparel, in a way to provide for such pre-conditioning during the operation of the vehicle. The materials, equipment and apparel is more ready for next time usage than if left wet or moist in the vehicle. Another advantage of the present invention is that children will be more comfortable in cold/wet environments, if the parents/guardians can attempt to, or specifically pre-condition (make dry, warm or make more dry or warm than previously) the apparel the children have been wearing without having to remove the material, equipment of apparel from the motor vehicle. Also, in preferred embodiments, no secondary source of pre-conditioning energy outside of that from the HVAC unit, need to be used. Pre-conditioning can run at any time the motor vehicle's HVAC unit is working, and, of course, quite beneficial, for example, in going from home or hotel to the ski slope or toboggan run.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a schematic view of ducts and branches for pre-conditioning apparel, in accordance with an aspect of the present invention
[0011] FIG. 2 is a schematic view describing a further embodiment of the pre-conditioning function, in accordance with an aspect of the present invention
[0012] FIG. 3 is a schematic view of the ducts and branches of the pre-conditioning systems, with typical dimensions as found, in accordance with an aspect of the present invention
[0013] FIG. 4 is a schematic view of the pre-conditioning system, including the vehicle interior, rear HVAC unit, HVAC distribution, device and branches with equipment to be pre-conditioned, in accordance with an aspect of the present invention.
[0014] FIGS. 5 a and 5 b are schematic views of a cold or warm box used in the preconditioning system, in accordance with an aspect of the present invention.
[0015] FIGS. 6 a and 6 b are schematic view of a preconditioning system, in accordance with an aspect of the present invention.
[0016] FIGS. 7 a and 7 b are schematic views of a preconditioning system and a boot with stand, in accordance with an aspect of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] In preferred embodiments of the present invention, a vehicle comprising an HVAC unit, and, more preferably, a rear HVAC unit, a device such as a duct or, preferably, a plurality of ducts, more preferably a duct or, preferably, a plurality of ducts from a rear HVAC unit, is provided. The HVAC unit and the device having at least one duct comprise an HVAC preconditioning system. Preferably, the duct has at least one branch, more preferably, two or more branches. The ducts of the preferred embodiment of the present invention can be single or multiple piece, preferably multiple piece ducts. By multiple piece, the ducts of the present invention can have detachable and/or interchangeable components, for example, a duct may be assembled using the components to form an angular, straight or curved path, depending on the configuration necessary to pre-condition the material, equipment or apparel necessary. For example, when using a preconditioning system of the present invention wherein a multitude of gloves and or boots need to be dried or warmed, a multitude of ducts and, preferably, branches of the ducts can be provided to condition the multitude of gloves and boots. When the need is to provide certain atmospheric drying or cooling conditions for one piece of equipment, such as a cold box or the like, the number of ducts and/or branches that provide conditioning air may be limited, i.e. a smaller number of ducts and/or branches used or provided, or a single duct or a single branch of a duct my provide conditioning air directly to the equipment or material, as necessary.
[0018] Also in preferred embodiments of the present invention, the ducts may have multiple branches that may be open or closed, depending on the need for condition for the particular material, equipment or apparel. For example, access to the branches themselves, and/or to a duct itself may be provided. More preferably, the branch or duct may have a mechanism to open or close a portion of the duct or branch to conditioning air flow, as necessary. The mechanism can be manual or automatic, most preferable the mechanism is mechanical (such as a cap or valve or flap or other such device) capable of shutting off or opening up conditioning air flow to the material, equipment or apparel from the HVAC unit duct or branch, as needed.
[0019] The HVAC preconditioning system of the present invention works in conjunction with various modes of the HVAC system. The HVAC system can, preferably, be in a fresh air mode, a recirculation mode or in a partial fresh/recirculation mode, depending on the conditions required. In preferred embodiments of the present invention, the HVAC preconditioning system is designed in a way to have an additional or a ‘third mode’ (first two being panel and floor modes normally for the preferred rear HVAC) and a drying type mode.
[0020] In preferred embodiments of the present invention, the device of the invention consists of at least one duct, and preferably, a plurality of ducts. The duct or ducts preferably have at least one branch or branches off of the duct or ducts for the air of the airflow from the HVAC unit to pass therethrough. Particularly preferred is ducts or branches of the ducts that are located on the duct end in an orientation suitable for use for preconditioning of the material, equipment, or apparel, as necessary. Either the duct or ducts and/or the branch or branches of the duct or ducts are, preferably, located in the rear luggage area or trunk region (if any) of the vehicle such that the material, equipment or apparel can be exposed directly to the air flowing through the duct or the branch to an open end of the duct of the branch where the material, equipment or apparel can be preconditioned. In the case of apparel such as foot apparel, the foot apparel could preferably be ‘inverted’ or placed upside down or sideways of the duct or branch open ends. Even more preferably, the foot apparel can be placed on a duct or branch at an angle that follows the angle of the duct or branch end where the duct or branch opens. More preferably, the duct or branch end can be positioned to be in a vertical orientation as it relates to the horizontal or ground, and the branch or branch with opening of the duct or branch, would accept the apparel to be placed in a similar relationship over the duct or branch open ends.
[0021] By placing the apparel wherein the opening or end of the duct or branch is in line with the opening or end of the shoe, boot, glove, or other similar apparel, for example, inserted into or at the shoulder or chest area of a sweater, coat, jacket, etc. or at the opening of the shoe, boot, glove, or other apparel, the duct and/or duct branches allow for the apparel to be hung or positioned such as to allow the air from the duct or branch to circulate, pass through, or otherwise pass over the apparel so that it pre-conditions the apparel via a drying and/or cooling process. In preferred embodiments of the present invention, the open ends of the ducts or branches of the ducts, could be placed in such a fashion as to allow for upward pointing or ‘upended’ ducts useful to pre-condition head gear (including hats, helmets and masks) or hand gear (including gloves and handwarmers) drying. The ducts, branches or ends of ducts would be such that they allow air from the airflow to enter and escape or exhaust easily from the apparel. In particularly preferred embodiments, ducts or branches are so aligned so that there is always the possibility for air to flow through or around the material, equipment or apparel, thereby avoiding the situation whereby apparel that is substantially airtight (i.e. tight weaved materials or solid materials) might unintentionally completely block off or choke or otherwise substantially hinder the free flow of drying or warming conditioning air.
[0022] The invention is driven by the currently designed preferable rear HVAC. Typically the vehicle segment or class which has the rear HVAC is usually a multi people carrier, SUV or truck. Such vehicles are used in more extreme weather transportation where the end user is interested in extended features to assist their comfort prior to and after partaking their said sport or activity. The current preferable rear HVAC is more than suitable with respect to design to add such functionality. The addition of such functionality is straight forward in a new design, an additional door position of the mode door, and or ‘wind blown self sealing flap’ could be added on the heater core exit side for example. The additional cost would be in a very simple set of blow-molded, injection molded or the like, such ducts or conduits. These ducts being removable and re-connectable to the preferable rear HVAC for summer storage.
[0023] The invention consists of a duct or ducts or conduit or conduits, with a branch or branches which feed appropriate amounts of hot, warm, dry air to the ends of the branches. The branch ends are situated such that apparel (preferably ski boots and gloves and hats) can be positioned, placed or pushed over the branches, such that the appropriate amount of hot, warm, dry air feeds into and specifically escapes from said apparel taking with it moisture, damp or wet air.
[0024] FIG. 1 illustrates a preferred embodiment of the present invention wherein glove apparel is illustrated. By using the heating and cooling capacity of the rear HVAC unit (not shown) in a vehicle such as a sport utility vehicle or minivan, for example, designed ducts ( 2 ), duct work ( 3 ) and branches ( 4 , 5 , 6 , 7 ) allow conditioned air 8 to be feed from the HVAC unit, through the ducts ( 8 , 3 ) and branches ( 4 , 5 , 6 , 7 ) and pass through the apparel ( 1 ) placed on the branches ( 4 , 5 , 6 , 7 ) of the duct ( 3 ). This concept, though not illustrated, can relate not only to boots and or gloves, but extended to a coat rack or racks, and snow suit or suits, or other apparel. Conditioning air, after passage through ducts 9 and, gloves, leaves via pores in apparel.
[0025] In preferred embodiments of the present invention, as in FIG. 2 , the branches bifurcate in a T ( 24 , 25 , 26 , 27 ) or Y ( 20 ) fashion. The branches, along, preferably, with their bifurcations, be integrally molded as an additional slot in additional feature for storage/drying warming of clothing. The T or Y type of bifurcation (though branches and ducts are not specifically limited to these shapes), is, in preferred embodiments, permeable, i.e. can be perforated ( 22 ) or the like, such that warm, dry air passes easily into the whole of the garment of the apparel.
[0026] FIG. 3 illustrates typical dimension of ducts A, branches C and main connector to HVAC unit conditioning air B in graphic form.
[0027] Referring to FIG. 4 is shown an automotive vehicle ( 40 ) with front HVAC unit ( 43 ), with floor ( 44 ) and defrost ( 42 ) outlets. The pre-condition system A has rear HVAC unit ( 45 ), device ( 46 ) with conditioning air stream ( 49 ) leading to a conditioning air at branches ( 49 a ) apparel ( 48 a ) and ( 48 b ) and equipment ( 47 ) in the rear compartment of the passenger vehicle.
[0028] Referring to FIG. 5 a a cool box ( 50 ) having a lid ( 51 ) and carrying handle ( 52 ) is provided with a feed duct ( 53 ) from the pre-conditioning system providing conditioning air ( 54 ) to cool the contents of the cool box ( 50 ). ( 50 ) could also be a warmer or warmbox, wherein the conditioning air ( 54 ) is warm air exhaust port ( 55 ) allows release of conditioning air from the system.
[0029] FIG. 5 b illustrates the cool or warmbox ( 56 ), with conditioned or conditioning air ( 57 ) flowing around the exterior of the box ( 58 ), and exhaust or spent air ( 59 ), exhausted from the system. Food, medical supplies or other content ( 60 ) that need to be kept under specific temperature and/or moisture conditions, are shown in box ( 56 ).
[0030] Referring to FIG. 6 a , auxiliary HVAC unit 120 has inlet 121 for air prior to conditioning, with heater core H and evaporator E and outlet 122 , conditioned air from outlet 122 provided or fed to main connector or coupling 123 , to supply conditioning air 100 to ducts 102 and branches 101 adapted for fitting of equipment or apparel (not shown) Conditioning air leaves branches as 103 .
[0031] FIG. 6 b shows similar system, with auxiliary front HVAC unit not shown, condition air 200 for HVAC unit supplying device 212 , with straight and curved ducts 202 , and branches 206 , leading to adapted end pieces 207 for placing apparel 205 over by sliding 204 apparel over adapted piece of duct branch.
[0032] FIG. 7 a illustrates HVAC unit with outlet ( 702 ) for air ( 703 ) of varying temperature and conditioning air, moisture content, main connector or coupling device 704 , with or without joint 705 feeding conditioning air into main duct ( 706 ) and branches ( 707 ), ( 708 ). Stand ( 709 ) is provided for placing or locating material, equipment or apparel (not shown). Conditioning feed air ( 110 ) to be provided to material, equipment or apparel is shown. Return or exhaust air ( 711 ) is also provided.
[0033] FIG. 7 b shows apparel, in this case, a boot ( 720 ) with stand ( 709 ), and conditioning feed air ( 710 ) entering boot and return air ( 711 ) exiting boot area. The present invention, via its preconditioning system, utilizes the heating and cooling capability of the HVAC to deliver hot, warm or cold or dried (air conditioned) air for purposes other that warming and cooling the cabin and or the passengers. In addition preferred embodiments of the present invention, the ducts and branches of the present invention could be extended to feeding or providing a cooler or cooler box that can be customized or more like a standard cool-box or cooler for goods, depending upon the specific needs of the end user. The conditioned air could be used to pre-condition perishables, for example, and keep them warm or cool during deliveries or pickups. Further, the present invention, in more of its more preferred embodiments, is adapted for ‘general’ thermal storage of medical supplies such as transplant organs or medicines
[0034] Though such a pre-conditioning system can be present at initial sale of a vehicle, the present invention also may be constructed after original sale of the vehicle. For example, the additional device necessary to form preferred embodiments of the present invention can be sold in the aftermarket as attachments or kits. In preferred embodiments, for example, the device that can be sold in such kits has ducts on the order of 5-25 cfm per square inch.
[0035] As described above, the rear HVAC unit is particularly preferred in preferred embodiments of the present invention. Rear HVAC units currently under production are typically capable of a dew-point of about 35° f. The thermal power available, after achieving the HVAC unit's primary goal of providing conditioned air to the passenger compartment, is, after the engine warm-up, still of the order of some 4-8 kW, i.e. of the order of a common US household clothes dryer.
[0036] Additionally, rear HVAC units in current production often have flow rates and control of air from about 50-250 scfm. This, too, is at a level comparable to a household clothes dryer.
[0037] The present invention, by utilizing, in its more preferred embodiments, the rear HVAC unit as part of its preconditioning system, with respect to power, flow, temperature and control, provides for efficient and effective preconditioning of materials, equipment and apparel, at a minimal overall cost to the end uses of the vehicle. The present invention, by providing for permanent, or detachable, or removable ducts, branches or conduits to deliver the appropriate air, provides for a pre-conditioning system that provides added comfort and value to the end user without significant cost.
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The present invention relates to an HVAC pre-conditioning system for vehicles, and, especially, automotive vehicles in the automotive and/or truck sector, which utilizes an HVAC unit, distribution system, and a device, such as ducts, useful for pre-conditioning via heating, cooling or drying material, equipment or apparel. By providing for a preconditioning system comprising at least one rear HVAC system and at least one duct or branch off of the a rear HVAC distribution system, conditioned or conditioning air can be used to pre-condition a number of sports, utility, and other materials such as clothing or other apparel, such as ski-boots, snow boots, walking shoes, working shoes and/or boots, gloves, hats, clothes and leg and body garments (children's snow-suits and scarves) are also envisioned. Other types of equipment, such as water skiing equipment with suitable catch trays, etc., could be dried out or made more comfortable using the present invention.
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BACKGROUND OF THE INVENTION
The present invention is applicable to substantially any process for drilling the borehole of a well with an oil-based drilling fluid in a location in which the wellbore may encounter hydrogen sulfide. Treatment of drilling fluid or mud is very important when drilling in areas where hydrogen sulfide (H 2 S) may be encountered. H 2 S is a highly toxic and corrosive acidic gas having, at low concentrations, the distinctive odor of rotten eggs. When H 2 S enters the drilling fluid, it reacts with the alkaline drilling fluid and is converted into bisulfides (HS - ) and sulfides (S -2 ).
The term "sulfides" as used here includes all water-soluble species, H 2 S, HS - , and S -2 , which co-exist in a sulfide-water system. The relative proportion of each species at equilibrium depends upon pH. For solutions with a pH of 7 to 13, typical for drilling fluids, bisulfides are the predominate species. If the pH drops below 7, H 2 S predominates, and above pH 13, sulfides predominate. Treatment of drilling mud with caustic soda and lime is often practiced where the presence of H 2 S is suspected. When soluble sulfide species accumulate in drilling mud, even small decreases in pH can generate large volumes of H 2 S gas in the drilling mud. To avoid reconversion of sulfides into H 2 S, it is common practice to react the sulfides into a more chemically inert form, such as precipitation as an insoluble metal sulfide.
The term "sulfide scavenger" refers to any drilling fluid additive that can react with one or more sulfide species and can convert them to a more inert form. Scavenger compounds are added to the drilling fluid at levels sufficient to provide a slight excess of scavenging compound over the amount of H 2 S present or anticipated in the drilling fluid in order to ensure quick and complete removal. Zinc-based additives, such as zinc carbonate, zinc hydroxide and organic zinc compounds, provide effective scavenging by a rapid and irreversible reaction with sulfides to form solid zinc sulfide. The most prevalent commercial zinc-based scavengers are Mil-gard (Milchem), Coat 45 (Baroid) and Sulf-X(IMCO).
Zinc is often the preferred metal ion to react with sulfide because of its compatibility with drilling fluid and its effectiveness in precipitating sulfide ions. U.S. Pat. No. 3,928,211 describes a process for scavenging H 2 S from aqueous drilling fluids and describes several known processes for removing H 2 S from drilling fluids. A class at zinc carbonate, basic zinc carbonate, and zinc hydroxide are listed as effective for scavenging sulfide. U.S. Pat. 4,252,655 covers a process for removing sulfide ions from both water and oil-based drilling fluids with organic zinc chelates.
If the hydrogen sulfide can be chemically bound while in the borehole, then it will not reach the surface in a potentially hazardous form. If the reaction is fast enough, and pretreatment concentrations of scavenger are adequate, then pipe failure due to corrosion can also be avoided. Limiting the amount of scavenger added to that required for effective control of H 2 S entering the mud reduces operating costs and lessens the change of impairing mud rheology by overtreatment.
Previous field testing methods for determining sulfide scavenger requirements in drilling operations have focused upon sulfide analysis. U.S. Pat. No. 3,928,211 mentions that the amount of zinc required for scavenging may be determined by analyzing the mud for sulfide. U.S. Pat. No. 4,252,655 suggests the need to monitor drilling mud for sulfide ions to determine when additional zinc chelate must be added. A device called the "Mud Duck" described in "H 2 S Detector Aids Drilling Safety", by S. H. Calmer in Oil and Gas Journal, Nov. 19, 1979, page 160, continuously measures the total soluble sulfides in any aqueous mud system using ion-selective electrodes, and relates these measurements to the dissolved H 2 S gas in equilibrium with the mud.
A state of the art paper entitled "Chemical Scavengers for Sulfides in Water Based Drilling Fluids" by R. L. Garrett, R. K. Clark, L. L. Carney and C. K. Grantham, Sr. in the Journal of Petroleum Technology, June, 1979, page 787, discusses the chemistry of commercial scavengers, the parameters that affect the reliability of such materials and the problems affecting scavenger use. The Garrett Gas Train method for sulfide analysis is described as a simple, yet accurate field procedure for monitoring sulfides in drilling fluid filtrate. The same article describes a method developed by a service company that uses titration to analyze for total alkaline-soluble zinc, but not the reacted zinc product, zinc sulfide. The authors also identified a need for realistic rig-site monitoring test to measure the amount of available scavenger in drilling fluid.
Although there are many analytical techniques available for the quantitative determination of zinc, few are capable of differentiating forms of the metal. Speciation capability is critical for isolating unspent scavenger from spent scavenger (zinc which has reacted with sulfide to form zinc sulfide). These analytical methods which can offer speciation capability (X-ray diffraction, photoelectron spectroscopy) are inappropriate for field applications due to cost, lack of ruggedness, size, or extensive utility requirements. One solution to this dilemma is to invoke a chemical separation prior to an analysis for total zinc by a field-worthy method.
SUMMARY OF THE INVENTION
The present invention relates to determining the amount of unspent zinc-based sulfide scavenger which is present in an oil-based drilling fluid and to adjusting the scavenging capability of the drilling fluid as required during the drilling of a well. More particularly, the invention relates to a relatively quick and accurate procedure for measuring unspent zinc-based scavenger, which can be used in field locations. A determination is made of the amount of unspent zinc-containing sulfide scavenging material present in the drilling fluid. A measured volume of the drilling fluid is mixed with a significantly larger number of volumes (such as about 6 to 10 or more) of a selective solvent for dissolving zinc ions, and establishing with the resulting mixture a pH (such as a Ph of from about 4 to 6) at which substantially all the zinc in the drilling fluid, except for that combined into zinc sulfide molecules, becomes dissolved in the aqueous phase of the mixture. A portion of the resulting aqueous solution is separated from the solid components and any oil component of the drilling fluid, and the amount of zinc contained in the solids-free liquid is then determined, in order to identify the amount of unspent zinc-containing sulfide scavenger in the drilling fluid.
This process enables the drilling fluid to be sampled at a selected frequency and the concentrations of unspent scavenger to be promptly available to the mud engineers. For example, within about 30 minutes or so, based on such information, increases or decreases can be made in the rate of scavenger addition and for addition of scavenger-free fluid to the extent needed to quickly change the scavenger concentration to either avoid an impairment of the drilling fluid rheology or to quickly scavenge a sudden encounter of sulfides.
DESCRIPTION OF THE INVENTION
Applicants have discovered that changes in the concentration of zinc-based scavenger in a drilling mud can be accurately monitored at the well site, so that corrections in the rate of scavenger addition can be initiated in a timely fashion. Experiments have been conducted using samples of an oil-based drilling fluid typical of that used in drilling operations.
In a preferred embodiment of the invention, the drilling fluid sample is mixed with about 4 to 10 times its volume of glacial acetic acid, or a selective solvent which is substantially equivalent to glacial acetic acid with respect to selectively dissolving zinc ions which have not combined with sulfide ions. The concentration of zinc in the aqueous phase of the resulting solution is preferably measured with a portable X-ray fluorescence spectrographic unit which is, or is substantially equivalent to, a Portaspec Model 2501 portable X-ray spectrograph (available from Pitchford Scientific Instruments Division of the Hankison Corporation). The simplicity of the procedure and the equipment required make this method particularly applicable for use in field locations.
A preferred procedure for determining unspent zinc-based sulfide scavenger is described below.
SAMPLE PREPARATION
1. Transfer 10 ml of well mixed mud, minimizing any particle size exclusion, into a 150 ml beaker.
2. Add 60 ml of glacial acetic acid.
3. Heat at about 110° C. with frequent stirring for 10-15 minutes.
4. Allow the solution to cool until it is lukewarm to the touch (sufficient to prevent damage to a plastic centrifuge tube).
5. Place a portion of the mud-acetic acid mixture into a plastic centrifuge tube.
6. Centrifuge so that all the solids are firmly packed at the bottom of the centrifuge tube.
7. Accurately pipet 10 ml of the aqueous portion of the centrifuge solution into a Chemplex X-ray fluorescence counting vial.
8. Cover the counting vial with polypropylene film.
MEASUREMENTS BY X-RAY FLUORESCENCE
1. Position the element selector to zinc using the sidearm lever.
2. Turn on the X-ray fluorescence machine. Wait for the "ready" light and let warm 10 minutes.
3. Place the sample counting vial in the spring-loaded mount. Insert the mount into the sample chamber with the rounded edge of the stainless mount facing inward.
4. With X-rays on, adjust the current to read 0.5 milliamps.
5. Set the counting scaler on the front panel to 60 seconds.
6. Engage count pushbutton and record the final gross X-ray intensity counts on the digital readout.
7. Obtain gross X-ray counts for the glacial acetic acid blank and a calibration standard prepared by the dissolution of zinc oxide in glacial acetic acid.
CALCULATIONS:
Basis: 10 ml mud, 60 ml acetic acid, 10 ml aliquots in counting vial. Calculations are not valid for variations from these amounts.
1. Determine the net counts for samples and the zinc oxide calibration standard by subtracting the glacial acetic acid blank counts.
2. Determine the mg of zinc in 10 ml mud sample by the following ratio: ##EQU1## 3. Determine pounds per barrel (lb/bbl) free zinc by multiplying the mg Zn in the 10 ml and sample by 0.035. The factor 0.035 is derived from the following conversion: ##EQU2##
The selective solvent for zinc ions can include substantially any buffered liquid having a composition and concentration capable of providing a pH of about 4 to 6 when one part by volume of a drilling fluid having a pH in the range of from about 9 to 12 is mixed with about 4 to 10 parts by volume of the solvent. Exmaples of suitable selective solvents solutions include: glacial acetic acid, 10% formic acid, and 0.0001M hydrochloric acid. The concentration of zinc which becomes dissolved in the selective solvent can be measured by substantially any suitably accurate procedure. Procedures capable of being conducted in the field locations are preferred.
In situations in which the proportions found of unspent zinc-based scavenger are relatively low, an augmentive test for total zinc (including that combined into zinc sulfide molecules) can be performed by (a) an X-ray fluorescence measurement, or equivalent measurement, of the zinc in the unleached drilling mud, or (b) using as the solvent for dissolving zinc from the drilling fluid a strong acid, such as hydrochloric acid, as a solvent, for combined and noncombined zinc, prior to measuring the concentration of the zinc solution. Such an acid preferably has a normality of from about 1 to 3. The difference between the prior and augmentive tests will indicate whether the scavenger concentration was reduced by dilution of the drilling fluid, or by combination with sulfide.
The above described analyses and calculations are performed at the drilling site with a frequency which increases with a likelihood of the borehold encountering sulfides, and/or increases in the extent by which the zinc-based scavenger is found to have been depleted by round trips of the circulating drilling fluid. The amount of scavenger in the mud can then be adjusted to the extent required to provide effective control of sulfides without impairing the drilling fluid reology. The zinc-based sulfide scavengers are generally available as solids, and can be added as dry solids through a hopper for mixing solids with the circulating drilling mud, but the scavengers are preferably added in the form of slurries in aqueous liquids. In addition, as known in the art, a lignosulfonate treatment of the drilling fluid can be utilized for controlling any undersirable zinc-induced flocculation of mud components.
Various modifications of the invention described will become apparent to those skilled in the art from the foregoing description, and such modifications are intended to fall within the scope of the appended claims.
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The concentration of unspent zinc-based hydrogen sulfide scavenger in an oil-based drilling fluid is controlled by selectively dissolving and extracting the unspent scavenger in a solvent, such as glacial acetic acid, separating the aqueous solution, measuring the concentration of dissolved zinc in the aqueous solution, for example, with an X-ray fluorescence spectrograph, and utilizing the results of the measurements to proportion the extent of changes in concentration of the scavenger in the drilling fluid.
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This application is a continuation of U.S. application Ser. No. 09/675,683, filed Sep. 29, 2000, now U.S. Pat. No. 6,561,999.
FIELD OF THE INVENTION
The present invention generally pertains to ophthalmic surgical procedures. More particularly, but not by way of limitation, the present invention pertains to combined anterior segment and posterior segment ophthalmic surgical procedures, as well as consumables utilized in such procedures.
DESCRIPTION OF THE RELATED ART
Ophthalmic surgical procedures are commonly classified as anterior segment surgical procedures, such as cataract surgery, and posterior segment procedures, such as vitreoretinal surgery. Traditionally, surgeons who performed anterior segment procedures did not typically perform posterior segment procedures, and vice versa. Therefore, two different sets of instrumentation and associated consumables were created for anterior segment surgery and posterior segment surgery. The Series 20000® Legacy® cataract surgical system, the Phaco-Emulsifier® aspirating unit, and their associated surgical cassettes, drainage bags, and tubing sets available from Alcon Laboratories, Inc. of Fort Worth, Tex. are examples of such anterior segment instrumentation and consumables. The Accurus® 400VS surgical system and its associated surgical cassettes, drainage bags, and tubing sets, are examples of such posterior segment instrumentation and consumables.
In posterior segment procedures involving phakic eyes, the crystalline lens may be surgically extracted. Such extraction is typically performed using posterior segment instrumentation (e.g. a vitrectomy probe) and consumables via a lensectomy. Due to the anatomical relationship of the lens to the scleratomies, a lensectomy requires the removal of the posterior lens capsule. The removal of the posterior lens capsule precludes the implantation of an intraocular lens (IOL) into the posterior chamber, the anatomically preferred location for IOL implantation. In addition, it is believed that the removal of the posterior lens capsule contributes to secondary complications such as cystoid macular edema.
Recently, a new procedure typically referred to as a combined anterior segment and posterior segment procedure, or “combined procedure”, has been developed. A posterior segment surgeon typically performs the combined procedure. In an uncomplicated combined procedure, the posterior segment surgeon first performs an anterior segment procedure, such as a cataract removal via phacoemulsification with posterior chamber IOL implantation, using an anterior segment surgical system and its associated consumables. The surgeon then immediately performs a posterior segment procedure using a separate posterior segment surgical system and its associated consumables. In more complicated combined procedures, the posterior chamber IOL implantation is often deferred until completion of the posterior segment procedure.
Even more recently, surgical systems have been developed that support both an anterior segment procedure and a posterior segment procedure via a single surgical console. An example of such a system is the Accurus® 600DS surgical system available from Alcon Laboratories, Inc. Two groups of consumables (surgical cassette, drainage bag, tubing sets) are currently available for use with this surgical system.
The first group of consumbables is the Accurus® Anterior Pak available from Alcon Laboratories, Inc., which is for use only in anterior segment procedures. A schematic representation of the consumables in the Accurus® Anterior Pak, in their assembled form, is shown in FIG. 1 . The Accurus® Anterior Pak includes a surgical cassette 10 having a vacuum chamber 12 , an irrigation inlet 14 , an irrigation outlet 16 , and an aspiration port 18 . As shown schematically in FIG. 1, a series of manifolds 22 fluidly couple vacuum chamber 12 , irrigation inlet 14 , irrigation outlet 16 , and an aspiration port 18 . Cassette 10 is disposed in a cassette receiving mechanism (not shown) in the Accurus® surgical system. As shown schematically in FIG. 1, the cassette receiving mechanism includes a series of occluder valves 24 and microreflux valves 26 for opening and closing various portions of manifolds 22 . Cassette 10 further includes a pump manifold 20 that is used to drain aspirated fluid from vacuum chamber 12 into a drain bag (not shown) connected to cassette 10 . A bottle 28 containing a conventional ophthalmic infusion fluid 30 , such as saline solution or BSS PLUS® intraocular irrigating solution available from Alcon Laboratories, Inc., is disposed above cassette 10 . Bottle 28 is not part of the Accurus® Anterior Pak. Bottle 28 is fluidly coupled to irrigation inlet 14 via tubing 32 . A conventional drip chamber 34 may be fluidly coupled between bottle 28 and tubing 32 . Tubing 36 is fluidly coupled to irrigation outlet 16 . The distal end 38 of tubing 36 is for fluidly coupling to a conventional irrigation handpiece, the irrigation inlet of a conventional irrigation/aspiration handpiece, or the irrigation inlet of a conventional ultrasonic handpiece. Tubing 40 is fluidly coupled to aspiration port 18 . The distal end 42 of tubing 40 is for fluidly coupling to the aspiration port of a conventional ultrasonic handpiece, or to the aspiration port of a conventional irrigation/aspiration handpiece. Tubing 32 , 36 , and 40 are preferably conventional medical grade flexible tubing.
The second group of consumbables is the Total Plus™ Pak available from Alcon Laboratories, Inc., which is for use only in posterior segment procedures. A schematic representation of the consumables in the Total Plus™ Pak, in their assembled form, is shown in FIG. 2 . The Total Plus™ Pak includes a surgical cassette 50 having a vacuum chamber 52 , a first aspiration port 54 , and a second aspiration port 56 . As shown schematically in FIG. 2, a first manifold 58 fluidly couples vacuum chamber 52 and port 54 , and a second manifold 60 fluidly couples vacuum chamber 52 and port 56 . Cassette 50 is disposed in a cassette receiving mechanism (not shown) in the Accurus® surgical system. As shown schematically in FIG. 2, the cassette receiving mechanism includes a series of occluder valves 62 and microreflux valves 64 for opening and closing various portions of manifolds 58 and 60 . Cassette 50 further includes a pump manifold 66 that is used to drain aspirated fluid from vacuum chamber 52 into a drain bag (not shown) connected to cassette 50 . Tubing 68 is fluidly coupled to aspiration port 54 . The distal end 70 of tubing 68 is for fluidly coupling to a conventional extrusion handpiece or a conventional ultrasonic handpiece used for pars plana lensectomy. Tubing 72 is fluidly coupled to aspiration port 56 . The distal end 74 of tubing 72 is for fluidly coupling to the aspiration port of a conventional vitrectomy probe. A bottle 28 containing a conventional ophthalmic infusion fluid 30 , such as saline solution or BSS PLUS® intraocular irrigating solution, is disposed above cassette 10 . Bottle 28 is not part of the Total Plus™ Pak. Bottle 28 is fluidly coupled to tubing 76 . A conventional drip chamber 78 may be fluidly coupled between bottle 30 and tubing 76 . A stopcock 80 is fluidly coupled to tubing 76 , and a stopcock 82 is fluidly coupled to stopcock 80 . Stopcocks 80 and 82 are preferably conventional three-way stopcocks. An outlet 84 of stopcock 82 is for fluidly coupling to a conventional infusion cannula. An inlet 86 of stopcock 80 is for fluidly coupling to a source of pressurized air that can be used to perform a fluid/air exchange during a posterior segment procedure. An inlet 88 of stopcock 82 is for fluidly coupling to a source of pressurized gas, such a perfluorocarbon gas, that can be used to perform a fluid/gas exchange, or an air/gas exchange, during a posterior segment procedure. Tubing 68 , 72 , and 76 are preferably conventional medical grade flexible tubing.
Therefore, the Accurus® 600DS surgical system, and its associated consumbables, greatly simplify the combined anterior segment and posterior segment ophthalmic surgical procedure. However, even with the Accurus® 600DS surgical system, a combined procedure requires the use of two separate sets of consumables. When changing from an anterior segment procedure to a posterior segment procedure, the surgeon and his or her staff must remove the anterior segment consumbables and set up the surgical system with the posterior segment consumbables. Therefore, a need continues to exist in the ophthalmic surgical field for ways to further simplify the combined anterior segment and posterior segment procedure for the surgeon.
SUMMARY OF THE INVENTION
The present invention is directed to a surgical cassette for use in a combined ophthalmic surgical procedure. The surgical cassette includes an irrigation inlet for receiving irrigation fluid from a source, a first irrigation outlet for providing irrigation fluid to a first ophthalmic microsurgical instrument, a first manifold fluidly coupling the irrigation inlet with the first irrigation outlet, a second irrigation outlet for providing irrigation fluid to a second ophthalmic microsurgical instrument, and a second manifold fluidly coupling the irrigation inlet with the second irrigation outlet. The surgical cassette greatly simplifies the combined procedure by eliminating the need for separate anterior segment and posterior segment cassettes for the combined procedure.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present invention, and for further objects and advantages thereof, reference is made to the following description taken in conjunction with the accompanying drawings in which:
FIG. 1 is a schematic view of a conventional set of anterior segment consumables in their assembled form;
FIG. 2 is a schematic view of a conventional set of posterior segment consumbables in their assembled form;
FIG. 3 is a front, perspective view of a surgical cassette for a combined ophthalmic surgical procedure according to a preferred embodiment of the present invention;
FIG. 4 is a rear, perspective view of the surgical cassette of FIG. 3;
FIG. 5 is a front, perspective view of the body of the cassette of FIG. 3;
FIG. 6 is a rear, perspective view of the body of the cassette of FIG. 3;
FIG. 7 is a front, perspective view of the cover of the cassette of FIG. 3;
FIG. 8 is a front schematic view of the fluidics of the cassette of FIG. 3;
FIG. 9 is a front schematic view of the cassette of FIG. 3 being used in a combined ophthalmic surgical procedure according to a preferred method of the present invention; and
FIG. 10 is a perspective, partially sectional view of a package for the cassette of the present invention and its associated consumables.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The preferred embodiment of the present invention and its advantages are best understood by referring to FIGS. 3 through 10 of the drawings, like numerals being used for like and corresponding parts of the various drawings.
FIGS. 3 through 8 illustrate a surgical cassette 100 according to a preferred embodiment of the present invention. Surgical cassette 100 is especially designed for use in a combined anterior segment and posterior segment ophthalmic surgical procedure, or “combined procedure”. Cassette 100 is preferably formed from a body 102 and a mating cover 104 made of conventional plastics. Cover 104 preferably has a handle 106 for grasping cassette 100 , and a header 107 . Cassette 100 also generally includes a vacuum chamber 108 , and irrigation inlet 110 , an anterior irrigation outlet 112 , a posterior irrigation outlet 114 , a general aspiration port 116 , a posterior aspiration port 118 , a first vacuum chamber port 120 , a second vacuum chamber port 122 , a third vacuum chamber port 124 , and a drainage bag port 126 . The locations of anterior irrigation outlet 112 and posterior irrigation outlet 114 may be reversed, if desired. As shown best in FIG. 6, vacuum chamber port 120 preferably has an oval-shaped geometry that is capable of receiving two manifolds made from conventional medical grade flexible tubing.
Irrigation inlet 110 is for fluidly coupling to a source of a conventional ophthalmic infusion fluid (not shown), such as saline solution or BSS PLUS® intraocular irrigating solution, via conventional medical grade flexible tubing. By way of example, the source of infusion fluid is preferably a bottle disposed above cassette 100 via a conventional IV pole.
Referring specifically to FIG. 8, the preferred routings of the various manifolds that define the fluidics of cassette 100 are schematically illustrated. Portions of a manifold on the front side of cassette 100 are designated with solid lines, and portions of a manifold on the rear side of cassette 100 are designated with dashed lines. All of the manifolds of cassette 100 are preferably made from medical grade silicone or other conventional, flexible plastic. More specifically, a manifold 130 fluidly couples irrigation inlet 110 and anterior irrigation outlet 112 . A manifold 132 fluidly couples irrigation inlet 110 and posterior irrigation outlet 114 . Manifolds 130 and 132 are preferably formed as an integral component. A manifold 134 fluidly couples general aspiration port 116 and first vacuum chamber port 120 . A manifold 136 fluidly couples posterior aspiration port 118 and first vacuum chamber port 120 . Manifolds 134 and 136 are preferably formed as an integral component. A conventional vacuum source is preferably fluidly coupled to second vacuum chamber port 122 via a console connection (not shown). This console connection is described in greater detail in U.S. Pat. No. 5,676,530, which is incorporated herein in its entirety by this reference. The conventional vacuum source is preferably part of a conventional ophthalmic surgical system capable of performing a combined procedure, such as the Accurus® 800 CS surgical system. A manifold 138 fluidly couples third vacuum chamber port 124 with drainage bag port 126 . Drainage bag port 126 is for fluidly coupling with a conventional drain bag (not shown) supported by flanges 140 .
Cassette 100 is for removably disposing in a conventional cassette receiving mechanism of a conventional ophthalmic surgical system such as the Accurus® 800 CS surgical system. The cassette receiving mechanism of the Accurus® surgical system is described in more detail in U.S. Pat. Nos. 5,676,530 and 5,588,815, which are incorporated herein in their entirety by this reference. When cassette 100 is disposed in the cassette receiving mechanism, second vacuum chamber port 122 is preferably fluidly coupled with a conventional source of vacuum within the surgical system. In addition, various portions of the manifolds located on the rear side of cassette 100 are positioned for operative engagement with various occluder valves and microreflux valves located in the surgical system. Each of these valves is preferably a conventional plunger valve that can be actuated to “pinch off” and close the manifolds in response to an electrical signal generated by the surgical system. The microreflux valves preferably have a slightly larger footprint than the occluder valves. More specifically, as shown in FIG. 8, manifold 130 is positioned for operative engagement with an occluder valve 142 . Manifold 132 is positioned for operative engagement with an occluder valve 144 . Manifold 134 is positioned for operative engagement with occluder valves 146 and 148 , and microreflux valves 150 and 152 . Manifold 136 is positioned for operative engagement with occluder valves 146 ,and 154 , and microreflux valve 150 . Furthermore, manifold 138 is positioned for operative engagement with a conventional peristaltic pump (not shown) disposed in the surgical system. Peristaltic pump opens and closes manifold 138 in order to pump aspirated ophthalmic tissue and fluid from vacuum chamber 108 , through third vacuum chamber port 124 , into manifold 138 , through drainage bag port 126 , and into the drain bag.
Having described the structure of the preferred embodiment of cassette 100 , the preferred method of using cassette 100 in a combined anterior segment and posterior segment ophthalmic surgical procedure in conjunction with a conventional ophthalmic surgical system will now be described in greater detail with reference to FIGS. 3 through 9. Cassette 100 is disposed in the cassette receiving mechanism of the conventional surgical system. A conventional source 160 of ophthalmic infusion fluid 30 is fluidly coupled to irrigation inlet 110 via tubing 162 . The source of ophthalmic fluid may be, by way of example, bottle 28 described hereinabove in connection with FIGS. 1 and 2. In addition, although not shown in FIG. 9, a tube providing pressurized air may be fluidly coupled to tubing 162 so as to provide different infusion pressures for fluid 30 without the necessity of moving source 160 to different heights above cassette 100 . One method of providing such different infusion pressures is to use a vented gas forced irrigation/infusion tubing set available from Alcon Laboratories, Inc. as tubing 162 . A conventional drain bag is attached to cassette 100 via flanges 140 . The bag is fluidly coupled to drainage bag port 126 in the conventional manner. A conventional ultrasonic handpiece 164 is fluidly coupled to cassette 100 . Ultrasonic handpiece 164 is preferably a phacoemulsification handpiece. More specifically, anterior irrigation outlet 112 of cassette 100 is fluidly coupled to irrigation inlet 166 of handpiece 164 via tubing 168 . In addition, aspiration port 170 of handpiece 164 is fluidly coupled to general aspiration port 116 of cassette 100 via tubing 172 . A conventional vitrectomy probe 174 is fluidly coupled to cassette 100 . Probe 174 may be pneumatically or electrically driven, and probe 174 may be a “guillotine style” or a “rotational style” vitrectomy probe. More specifically, aspiration port 176 of probe 174 is fluidly coupled to posterior aspiration port 118 of cassette 100 via tubing 178 . A conventional infusion cannula 180 is fluidly coupled to cassette 100 . More specifically, port 182 of cannula 180 is fluidly coupled to posterior irrigation outlet 114 of cassette 100 via tubing 184 . Tubing 168 , 172 , 178 , and 184 are preferably conventional medical grade flexible tubing. Although not shown in FIG. 9, ultrasonic handpiece 164 may be replaced with a conventional irrigation handpiece or a conventional irrigation/aspiration handpiece for certain anterior segment procedures.
The surgeon typically then performs the anterior segment portion of the combined procedure using ultrasonic handpiece 164 . More specifically, the surgeon selects an anterior segment mode on the conventional surgical system. The anterior segment mode is utilized to control ultrasonic handpiece 164 . In the anterior segment mode, the surgical system actuates occluder valve 142 to open manifold 130 , allowing infusion fluid to flow from irrigation inlet 110 to anterior irrigation outlet 112 . During the procedure, occluder valve 142 may be actuated via the surgical system to start or stop this flow of irrigation fluid as desired. The surgical system also actuates occluder valve 144 to close manifold 132 , preventing the flow of infusion fluid from irrigation inlet 110 to posterior irrigation outlet 114 . The surgical system also actuates occluder valves 146 and 148 to open manifold 134 , providing vacuum to general aspiration port 116 . The surgical system further actuates occluder valve 154 to close manifold 136 , stopping vacuum to posterior aspiration port 118 . Ultrasonic handpiece 164 may then be utilized to perform the anterior segment portion of the combined procedure. During the procedure, cassette 100 provides infusion fluid 30 to infusion inlet 166 of handpiece 164 via anterior irrigation outlet 112 and tubing 168 to cool the tip of handpiece 164 at the intraocular incision and to replace aspirated fluid and tissue. Cassette 100 also provides vacuum to aspiration port 170 of handpiece 164 via general aspiration port 116 and tubing 172 . Such vacuum removes ophthalmic tissue and fluid aspirated by handpiece 164 into vacuum chamber 108 via tubing 172 and manifold 134 .
During the anterior segment portion of the combined procedure, a surgeon may need to perform a microreflux operation if, by way of example, portions of the posterior capsule or iris become too close to the cutting tip of ultrasonic handpiece 164 . The microreflux operation causes a small pressure wave or impulse to be sent from cassette 100 to aspiration port 170 of ultrasonic handpiece 164 by displacement of a small bolus of fluid within the manifolds of cassette 100 . This pressure wave exits the tip of ultrasonic handpiece 164 and moves the posterior capsule or iris away from the tip of handpiece 164 . More specifically, occluder valve 154 has already been actuated to close manifold 136 , and occluder valve 148 has already been actutated to open manifold 134 , at the beginning of the anterior segment mode. The surgical system actuates occluder valve 146 to close manifold 134 . The surgical system then actuates microreflux valve 150 to momentarily close manifold 134 , displacing fluid and creating a pressure wave that will exit through port 116 . Once the advancing pressure wave passes microreflux valve 152 , the surgical system preferably actuates microreflux valve 152 to close manifold 134 , augmenting the pressure wave. The pressure wave exits port 116 and travels through tubing 172 and aspiration port 170 of handpiece 164 and out through the tip of the handpiece. The surgical system then closes occluder valve 148 and opens occluder valve 146 , before opening microreflux valves 150 and 152 , to prevent microaspiration. If timed correctly, this closing of occluder valve 148 may also augment the microreflux pressure wave. The surgical system reopens occluder valve 148 to continue normal anterior segment aspiration.
The surgeon then typically performs the posterior segment portion of the combined procedure using vitrectomy probe 174 and infusion cannula 180 . More specifically, the surgeon selects a posterior segment mode on the conventional surgical system. The posterior segment mode is used to control probe 174 and cannula 180 . In the posterior segment mode, the surgical system actuates occluder valve 144 to open manifold 132 , allowing infusion fluid to flow from irrigation inlet 110 to posterior irrigation outlet 114 . During the procedure, occluder valve 144 may be actuated via the surgical system to start or stop this flow of irrigation fluid as desired. The surgical system also actuates occluder valve 142 to close manifold 130 , preventing the flow of infusion fluid from irrigation inlet 110 to anterior irrigation outlet 112 . The surgical system also actuates occluder valves 146 and 154 to open manifold 136 , providing vacuum to posterior aspiration port 118 . The surgical system further actuates occluder valve 152 to close manifold 134 , stopping vacuum to general aspiration port 116 . Vitrectomy probe 174 and infusion cannula 180 may then be utilized to perform the posterior segment portion of the combined procedure. During the procedure, cassette 100 provides infusion fluid 30 to port 182 of cannula 180 via posterior irrigation outlet 114 and tubing 184 to maintain appropriate intraocular pressure of the eye. Cassette 100 also provides vacuum to aspiration port 176 of probe 174 via posterior aspiration port 118 and tubing 178 . Such vacuum removes ophthalmic tissue and fluid aspirated by probe 174 into vacuum chamber 108 via tubing 178 and manifold 136 .
During the posterior segment portion of the combined procedure, a surgeon may need to perform a microreflux operation if, by way of example, portions of the retina become too close to the cutting port vitrectomy probe 174 . The microreflux operation causes a small pressure wave or impulse to be sent from cassette 100 to aspiration port 176 of vitrectomy probe 174 , by displacement of a small bolus of fluid within the manifolds of cassette 100 . This pressure wave exits the cutting port of probe 174 , and moves the retina away from the cutting port of probe 174 . More specifically, occluder valve 148 has already been actuated to close manifold 134 , and occluder valve 154 has already been actuated to open manifold 136 , and the beginning of posterior segment mode. The surgical system actuates occluder valve 146 to close manifold 136 . The surgical system then actuates microreflux valve 150 to momentarily close manifold 136 , displacing fluid and creating a pressure wave that exits through port 118 . This pressure wave travels through tubing 178 and aspiration port 176 of probe 170 and out through the cutting port of the probe. The surgical system then closes occluder valve 154 and opens occluder valve 146 , before opening microreflux valve 150 , to prevent microaspiration. If timed correctly, this closing of occluder valve 154 may augment the microreflux pressure wave. The surgical system reopens occluder valve 154 to continue normal posterior segment aspiration.
In both the anterior segment portion and the posterior segment portion of the combined procedure, aspirated ophthalmic tissue and fluid is removed from vacuum chamber 108 into a drain bag via third vacuum chamber port 124 , manifold 138 , and drainage bag port 126 . This aspirated fluid is removed via the operative engagement of a peristaltic pump with manifold 138 as described hereinabove.
FIG. 10 illustrates an exemplary package 300 for housing cassette 100 and its associated consumables for distribution purposes. Package 300 generally includes a body 302 and a cover 304 . Body 302 has an interior 306 and an opening 308 . Body 302 is preferably formed from conventional plastics in a shape to conveniently store cassette 100 and its associated consumables. Cover 304 is removably coupled to body 302 and is disposed over opening 308 . Cover 304 is preferably formed from a breathable, porous material, such as, by way of example, high density polyethylene. A preferred material for cover 304 is Tyvek® available from E. I. duPont de Nemours and Company of Wilmington, Del. Cover 304 is preferably removably coupled to body 302 via an adhesive. Package 300 is preferably suitable for sterilization via conventional gamma radiation or ethylene oxide processes.
It will be apparent to those skilled in the art that the surgical system may actuate the occluder valves of cassette 100 to provide irrigation from anterior irrigation outlet 112 and posterior irrigation outlet 114 simultaneously, or to prevent irrigation from both irrigation outlet 112 and posterior irrigation outlet 114 , if desired. Similarly, the surgical system may actuate the occluder valves of cassette 100 to provide for vacuum from general aspiration port 116 and posterior aspiration port 118 simultaneously, or to prevent vacuum to both general aspiration port 116 and posterior aspiration port 118 , if desired.
From the above, it may be appreciated that the present invention provides a surgeon with a simplified method of performing a combined anterior segment and posterior segment ophthalmic surgical procedure. Significantly, using the present invention, the surgeon no longer must changeover the surgical system from anterior segment consumables to posterior segment consumables in order to complete the combined procedure.
It is believed that the operation and construction of the present invention will be apparent from the foregoing description. While the apparatus and methods shown or described above have been characterized as being preferred, various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the following claims.
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A surgical cassette for use in a combined anterior segment and posterior segment ophthalmic surgical procedure is disclosed. The surgical cassette includes an irrigation inlet for receiving irrigation fluid from a source, a first irrigation outlet for providing irrigation fluid to a first ophthalmic microsurgical instrument, a first manifold fluidly coupling the irrigation inlet with the first irrigation outlet, a second irrigation outlet for providing irrigation fluid to a second ophthalmic microsurgical instrument, and a second manifold fluidly coupling the irrigation inlet with the second irrigation outlet. The surgical cassette greatly simplifies the combined procedure by eliminating the need for separate anterior segment and posterior segment cassettes for the combined procedure.
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BACKGROUND OF THE INVENTION
[0001] Field of the Invention
[0002] The invention relates generally to exercise equipment and in particular to a body alignment and correction device.
[0003] Background Art
[0004] Exercise equipment, particularly when used in an athletic club, has become very popular. Unfortunately, to put it simply, most people who are working out are doing it wrong. They hold their bodies and limbs in incorrect positions, resulting in repetitive motion injuries, imbalanced development of their muscle groups, and other long-term problems that are easily avoided with the correct posture and limb positioning. A body alignment and correction device, which secures the user's body and limbs in the correct positions when working out, would resolve this problem.
SUMMARY OF THE INVENTION
[0005] Accordingly, the invention is directed to a body alignment and correction device. The device provides a rectangular platform, with a front post and a rear post which unfold and telescope into position. Carabiner clips are provided along the sides of the platform. Various elastic and other workout attachments may be clipped to the carabiner clips, and to the upper ends of the front post and rear post, providing resistance for the user during a workout. An adjustable, removable claw attachment on the rear post secures the user's shoulders and upper body in the correct alignment during the workout. Four retractable caster wheels at the corners of the platform enable the user to easily move the device around the workout area as desired.
[0006] Additional features and advantages of the invention will be set forth in the description which follows, and will be apparent from the description, or may be learned by practice of the invention. The foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The accompanying drawings are included to provide a further understanding of the invention and are incorporated into and constitute a part of the specification. They illustrate one embodiment of the invention and, together with the description, serve to explain the principles of the invention,
[0008] FIG. 1 is a side perspective view of the first exemplary embodiment in the unfolded position, displaying the platform 10 , the front post 11 , the rear post 12 , the claw attachment 12 A, the carabiner clips 13 , the barbell table 14 , and the workout attachments 15 ;
[0009] FIG. 2 is a side perspective view of the platform component of the first exemplary embodiment in the folded position, displaying the platform 10 , and the caster wheels 10 A;
[0010] FIG. 3 is a rear view of a portion of the belt component of the first exemplary embodiment;
[0011] FIG. 4 is a rear view of the belt component of the first exemplary embodiment;
[0012] FIG. 5 is a front view of belt component of the first exemplary embodiment in a reverse bent position;
[0013] FIG. 6 is a perspective view of an embodiment of the belt of the invention, without blocks.
[0014] FIG. 7 is a perspective view of an embodiment of the belt of the invention with a pair of blocks positioned on the rear or inside surface of the belt.
[0015] FIG. 8 is a top view of the belt with blocks positioned on the abdomen of the user.
[0016] FIG. 9 is a perspective view of a block with an enclosure and attachment assembly.
[0017] FIG. 10 is a side elevation view of the block of FIG. 9 , with breakouts showing composition of the block.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0018] Referring now to the invention in more detail, the invention is directed to a body alignment and correction device.
[0019] The first exemplary embodiment is comprised of a body alignment and correction device for use during workouts. The device provides a rectangular platform 10 , with a front post 11 and a rear post 12 which unfold and telescope into position, rotate fully through a 180° arc, and may be locked into position at any length or angle as desired. Carabiner clips 13 are provided along the sides of the platform 10 . Various elastic and other workout attachments 15 may be clipped to the carabiner clips 13 , and to the upper ends of the front post 11 and rear post 12 , providing resistance for the user during a workout.
[0020] An adjustable, removable claw attachment 12 A on the rear post secures the user's shoulders and upper body in the correct alignment during the workout. A removable barbell table 14 may be secured to the platform 10 , enabling the user to work out with barbells or other hand weights while secured in the correct posture by the claw attachment 12 A. Four retractable caster wheels 10 A at the corners of the platform 10 enable the user to easily move the device around the workout area as desired. The platform 10 is hinged in the center such that it may be folded in half for easy transport and storage.
[0021] A broad, padded belt 16 is provided, with hook-and-loop fasteners 21 at either end. The belt 16 is preferably 3-4 inches wide. The layers of the belt 16 are affixed to each other with snaps 17 . The layers of the belt 16 may also be fastened with other fastening devices such as zippers and hook and loop fasteners. The layers of the belt 16 may also be sewn together with stitching. Flat bands 19 , terminating in rings or carabiner style belt clips 18 , are provided on the front and rear surfaces of the belt 16 , which may be used as drawstrings to tighten and secure the belt 16 around the user's waist, or secure the user's body to the device.
[0022] In other embodiments the bands 19 may each terminate in a complimentary buckle member 30 a and 30 b as shown in FIGS. 6 and 7 , so that the bands 19 may be fastened in front of the user when worn. The bands 19 may also include adjustment buckles 35 so that the bands 19 may be adjusted in length. In other embodiments, the buckles 35 may be used to join or connect portions of the bands that have different characteristics, such as elasticity. A ring 36 may also be attached near the buckle members 30 a and 30 b on each band 19 . The bands 19 are preferably 1.5 inches wide, and covered for two-thirds of their length with neoprene sleeves. Divots and snaps 17 hold the neoprene sleeves together. However, in some embodiments, the bands need not be covered.
[0023] The snaps 17 enable the user to remove and replace the bands 19 if they are broken or worn out, or if the belt 16 needs to be laundered. The foam blocks 20 may be positioned such that they are just above the kidneys on the back for users who are flexion intolerant. This allows the belt 16 to only contact the user's abdomen, not the lower back. Alternatively, the foam blocks 20 may be positioned such that they are just above the hip bones in front for users who are extension intolerant. This allows the belt 16 to only contact the user's lower back, not the abdomen.
[0024] In other embodiments, as shown in FIG. 6 , the bands 19 may include an elastic portion 40 . The elastic portion 40 is preferably attached to the belt 16 at the midpoint of the belt length. The elastic portion 40 may be secured to the belt by any means known. As shown in FIG. 6 , the elastic portion 40 is secured to the midpoint of the belt 16 by stitching 45 . While the entire band 19 may be made of elastic, in the most preferred embodiment the elastic portion 40 is attached to an inelastic portion 41 . The elastic and inelastic portions may be attached to one another by stitching, snaps, buckles, or any other mechanism known to attach bands. As shown in FIG. 6 , each band portion includes a loop, which is fitted through a buckle 35 . In the most preferred embodiment, buckles 35 is an adjustment buckle which allows the user to adjust the overall length of the bands 19 . In other embodiments, the length of the bands 19 may be adjusted at the buckles 30 a and 30 b . In other embodiments, buckle 35 may be omitted and the portions of the bands may be joined to each other with stitching.
[0025] As shown in FIG. 6 , the belt 16 may include an additional piece of material about a portion of its length to partially conceal the bands 19 . In the preferred embodiment shown in FIG. 6 , the additional piece of material 60 is approximately ¼ of the length of the belt 16 , and is located about the midpoint of the belt's length. With such a location, it is generally to the rear of the user when the belt is worn. As shown in FIG. 6 , the additional piece of material 60 is fastened to the outer or front surface 32 of the belt 16 so as to form a tunnel in which a portion of the band 19 , may run or reside. The outer or front surface 32 of the belt is the surface that is away from the user when the belt is worn. Specifically as shown in FIG. 6 , the elastic portion 40 of the bands 19 is partially covered by the additional piece of material 60 . In the preferred embodiment shown in FIG. 6 , the upper and lower perimeter edges of the additional piece of material 60 are sewn or otherwise fastened to the front surface 32 of the belt 16 . In other embodiments, the additional piece of material 60 may be omitted and the tunnel created between the front surface 32 and the rear surface 31 of the belt. In other words, the bands 19 are positioned for part of their length, between the front surface 32 and rear surface 31 of the belt 16 .
[0026] Foam blocks 20 are also provided, and affixed to the belt 16 such that when the belt 16 is worn, the foam blocks 20 are located on or below the user's kidney area. In the preferred embodiment, the dimensions of the foam blocks 20 are approximately 2.5″ (thickness)×3″ (width)×4.5″ (length). The foam blocks 20 are preferably made of at least two types of foam to provide a firmer base of support nearer the belt 16 . In the most preferred embodiment, the foam blocks 20 are constructed of a first layer of high density foam 22 , and a second layer of lower density foam 23 . The high density foam 22 is preferably 0.5 inches thick, and the lower density foam 23 is approximately 2 inches thick. The high density foam is positioned nearer the rear surface 31 of the belt 16 . Such positioning helps the foam block 20 maintain its shape and resist rolling or the formation about the belt 16 .
[0027] The foam blocks 20 are removable in the event that the user wishes to rely on the pull of the bands 19 . In the most preferred embodiment, the rear surface 31 of the belt 16 which is the surface that faces the user when the belt 16 is worn, may include hook and loop fastener 70 material on a portion of its length to allow the foam blocks 20 , or enclosures or coverings 37 for the foam blocks, to be selectively attached at various positions along the belt 16 . In such an embodiment, the surface of the foam block 20 or its enclosure or covering 37 has a hook or loop fastener on the outer surface that is complimentary to the fastener on the rear surface of the belt 16 . In some embodiments, the front surface 31 of the belt will include hook and loop fastener 70 material on substantially the entire length of the belt 16 . The presence of the hook and loop fastener 70 material on substantially the entire length of the belt 16 , allows the foam blocks 20 or the enclosure 37 having complementary hook and loop fastener 70 material placed on its exterior, to be positioned anywhere on the rear surface 31 of the belt 16 . With such positioning options, the user may easily move the foam blocks 22 to contact the users back or abdomen as desired.
[0028] The foam blocks 20 are preferably placed in an enclosure or covering 37 , as shown in FIGS. 9 and 10 . This prevents deterioration of the foam blocks 20 from abrasion or contact with the user's perspiration. The enclosure or covering 37 preferably covers all sides of the blocks 20 and includes a closure such as a zipper 38 to allow a block to be inserted and removed. This is of benefit if the enclosure or covering 37 becomes soiled and needs laundering. As shown in FIGS. 9 and 10 , the zipper 38 is preferably placed about the perimeter of a surface of the enclosure 37 . In the most preferred embodiment, the zipper 38 is about the surface of the enclosure that attaches or abuts the belt 16 when the block is placed on the belt 16 . In the most preferred embodiment, the zipper 38 ends adjacent to a block securing assembly that is used to attach and further secure the enclosure or covering 37 to the belt. In such an arrangement, when the zipper is closed, the zipper pull or tab is placed underneath a portion of the securing assembly so that the zipper pull is restrained and does not move about as the user exercises.
[0029] The enclosure or covering 37 preferably also includes hook or oop fasteners 70 on at least one outer surface so that it may be attached to selected locations about the rear surface of the belt 16 . In the preferred embodiment, the loop portion of the fasteners are located on the rear surface 31 of the belt 16 , and the complimentary loop portions are on the block enclosure or covering 37 .
[0030] The enclosure or covering 37 may also include a block securing assembly to further secure the blocks 20 to the belt 16 . The block securing assembly generally connects the top and bottom of a block, enclosure, or covering 37 , and is positioned so that the belt 16 is captured between a strap 52 of the assembly and a block 20 and its enclosure or covering 37 . The strap 52 of the preferred embodiment is a length of webbing approximately 2 inches wide and 7 inches in length. The block securing assembly includes a slotted loop or buckle 39 attached directly, or by a web 57 , to the top of the enclosure or covering 37 , and an end 51 of the strap 52 is attached to the bottom of the enclosure or covering 37 . In the preferred embodiment shown in FIGS. 9 and 10 , the web 57 is attached to the top surface of the enclosure 37 with two lines of stitching so as to form a tunnel into which the zipper pull may be placed when the zipper 38 is closed. The web 57 may be made of an elastic material. In such an event, the tunnel may be easily stretched and lifted by the user, allowing the zipper pull to be inserted into the tunnel and held secure. With the enclosure or covering 37 positioned on the rear surface 31 of the belt 16 , the strap 52 is positioned so that it is proximate to the front surface 32 of the belt 16 , and the free end 51 of the strap 52 is fed through the slotted loop 39 . The strap 52 is then pulled tight and secured against itself with fasteners, such as snaps or complimentary hook and loop fasteners as shown in FIGS. 7, 9, and 10 .
[0031] In such an embodiment, the strap 52 has an inner surface 53 and an outer surface 54 . On a first portion of the outer surface 44 is attached the hook, portion 70 a of the hook and loop fasteners 70 , and on a second portion of the outer surface 54 is attached the loop portion 70 b of the hook and loop fasteners. In the preferred embodiment the portions of the strap 52 each occupy approximately ½ of the entire length of the strap 52 . With this arrangement, when the strap 52 is pulled tight, the first portion of the strap 52 is pulled through the slotted loop 39 to and is then folded about the slotted loop 39 allowing the hook fasteners 70 a on the first portion to be secured against the loop fasteners 70 b on the second portion of the strap 52 . The free end 51 of the strap 52 is thereby positioned at or near the lower end of the block 20 or enclosure or covering 37 . In the most preferred embodiment, the free end 51 extends no more than a half inch below the lower end of the enclosure 37 . One skilled in the art will recognize that the hook and loop fasteners may be substituted for one another. However one skilled in the art will also realize that it is preferable to have the loop fasteners 70 b positioned in areas that will be exposed to the user or the user's clothing, as the hook fasteners 70 a can be rough and abrasive. This observation holds true not just for the coverings or enclosures 37 but also for the positioning of the hook and loop fasteners 70 on the belt 16 .
[0032] To use the first exemplary embodiment, the user may place the platform 10 in the workout area, extend the front pole 11 and the rear pole 12 at any angle and to any length desired, and lock them into position. The user may then attach one or more workout attachments 15 to the carabiner clips 13 , or the upper ends of the front pole 11 and the rear pole 12 as desired. The user may secure the claw attachment 12 A to the rear pole 12 at the desired height, then secure the claw attachment 12 A to the shoulders and upper body, pick up the workout attachments 15 , and being the workout. Alternately, the user may secure the barbell table 14 to the platform 10 and work out with barbells or other hand weights, or the user may wear the belt 16 around the waist and secure the claw attachment 12 A to the belt 16 ,
[0033] When finished with the workout, the user may extend the caster wheels 10 A and roll the platform 10 wherever desired. Alternately, the user may detach the barbell table 14 or the workout attachments 15 , and remove the claw attachment 12 A. Then the user may unlock, retract, and fold the front post 11 and the rear post 12 , and fold up the platform 10 for transport or storage,
[0034] The device is a flexion extension dominant system, which determines the environment wherein a particular human body will function at its highest level. This theory was derived from the rehabilitation concepts of flexion intolerance and extension intolerance. Flexion intolerance is posterior chain weakness, while extension intolerance is anterior chain weakness. When the intolerance is observed, the therapist can determine the injury trail a patient may have and lifestyle influences such as employment and sports wherein the patient would excel. This information could substantially impact future wear and tear on joints, direction of an athlete in particular sports, and which employment career is best suited for an individual. It is also observed that this may have an influence on the learning styles of various people based on environments.
[0035] It is found that flexion intolerant people have possible damage to the spine where it is advised for them not to crunch or flex the spine. However, they need to keep their abdominal muscles stimulated by weight behind them, such as a backpack or band, or pressure against the lower abdominal muscles. If not stimulated, their posterior muscles will not activate. These people tend to prefer standing more than sitting, and they tend to lean on objects such as tables and counters for relief. These, people like to sleep on the side or the stomach. They tend to have weak hamstrings, biceps, shoulders, upper trapezius, upper chest, lower back, and calves. The common overuse injuries are plantar fasciitis, ACL tears, bicipital tendinitis, low back injuries like herniations, lordosis, and neck issues. Diastasis is also noted. These people tend to prefer activities where they push down, lift a knee, or use their abdominal muscles, such as mopping floors, massage, hiking uphill, and picking up items from the floor or lower shelves. Sports these people excel in are sprinting, hockey, wrestling, kickboxing, and soccer. Careers these people excel in are massage therapy, construction, flooring installation, and cleaning. These people tend to comprehend best while looking down or writing, such as highlighting a book or using an iPad. The belt 16 of the device is worn where it touches the abdominal muscles and not the lower back, or a band can be worn touching the abdominal muscles and pulling the hips backward where a flexion intolerant person must engage the posterior chain. This pull allows for the shoulders and hamstrings to activate properly and develop. The belt 16 , the device, and the cardio attachments can help elicit this force to produce proper body mechanics that traditional exercises are missing.
[0036] It is found that extension intolerant people have possible damage to the spine where it is advised for them not to hyperextend the spine or dead lift. However, they need to keep their lower back or extensor muscles stimulated by weight in front of them, such as a front pack below the neck, or by a band, or pressure against the lower back. If not stimulated, their posterior muscles will not activate. These people tend to like to sit and sleep on their sides or their backs. They tend to have weak quadriceps, latissimus dorsi, lower chest, abdominals, gluteus, and triceps. The common overuse injuries are Achilles tendinitis, Achilles rupture, meniscus tears, quadriceps tears, hip pain, slipped discs, torn rotator cuffs, cervical problems, kyphosis, tennis elbow, and carpal tunnel. Hernias are also noted. These people tend to like activities where they stand tall, extend their arms above the head, sit up straight, and hold weight in front of them. Sports these people tend to excel in are gymnastics, basketball, baseball, golf, distance running, tennis, and dance. Careers these people excel in are hairdressing, computer jobs, servers, drivers, and painters. These people tend to comprehend best while looking up or leaning back in a chair or bed. They tend to do better with desktop computers. The belt 16 of the device is worn where it touches the lower back and not the abdominal muscles, or a band can be worn touching the lower back and pulling the hips forward where an extension intolerant person must engage their anterior chain. This pull allows for the latissimus dorsi, abdominals, gluteus and quadriceps to properly activate and develop. The belt 16 , the device, and the cardio attachments can help elicit this force to produce proper body mechanics that traditional exercises are missing.
[0037] The device will improve health care, injury prevention, and rehabilitation, lowering incidences of injury and speeding up rehabilitation. Work related injuries which will be reduced include lower back, knees, carpal tunnel, neck, and headaches. The device will assist in directing people into sports and careers, including military specialties, that are compatible with their body type. The device may help improve sexual enjoyment and fertility, indicating which positions may be most suitable. The device will help with exercise and obesity control, since people do not like to experience pain when working out, and a pain-free workout is more likely to be completed regularly. The device will help with sleep positions and the selection of vehicles, chairs, and other furniture to prevent discomfort, generally improving comfort and quality of life. The device will also improve cognition and learning by informing the user regarding the best positions for reading.
[0038] The platform 10 and the barbell table 14 are preferably manufactured from a rigid, durable material, such as steel, aluminum alloy, or wood. The caster wheels 10 A are preferably manufactured from a rigid, durable material such as steel or aluminum alloy, providing solid tires which are preferably manufactured from a flexible, durable material such as rubber or silicone. The front post 11 , the rear post 12 , and the carabiner clips 13 are preferably manufactured from a rigid, durable material such as steel or aluminum alloy. The claw attachment 12 A is preferably manufactured from a rigid, durable material such as steel or aluminum alloy, coated with a flexible, durable material such as rubber or silicone.
[0039] The workout attachments 15 are preferably manufactured from a variety of rigid, durable materials such as steel, aluminum alloy, plastic, and wood, and flexible, durable materials such as rubber and nylon webbing. The belt 16 is preferably manufactured from a flexible, durable material such as nylon webbing. The snaps 17 and the belt clips 18 are preferably manufactured from a rigid, durable material such as plastic or steel. The bands 19 are preferably manufactured from a flexible, durable material with a substantial elastic quality, such as rubber, covered for two-thirds of their length by sleeves which are preferably manufactured from a flexible, durable material such as neoprene.
[0040] The foam blocks 20 are preferably manufactured from a semi-rigid, durable material such as foam rubber. The fasteners 21 are preferably manufactured from a flexible, durable material such as plastic or nylon. Components, component sizes, and materials listed above are preferable, but artisans will recognize that alternate components and materials could be selected without altering the scope of the invention. Further on skilled in the art will recognize that when the application refers to foam blocks or block, the reference can refer to foam block alone, or foam blocks with an enclosure or covering or other assemblies to allow the blocks to be secured on the belt 16 .
[0041] While the foregoing written description of the invention enables' one of ordinary skill to make and use what is presently considered tube the best mode thereof, those or ordinary skill in the art will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should, therefore, not be limited by the above described embodiment, method, and examples, but by all embodiments and methods within the scope and spirit of the invention.
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The body alignment and correction device disclosed herein includes a belt for wearing about the waist of a user. The device further includes removable and repositionable foam blocks to displace portions of the belt away from the user's body. A method of stimulating abdominal or back muscles of a user of the device by selectively placing foam blocks to space a portion of the belt away from a user's body is also disclosed.
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TECHNICAL FIELD
[0001] The present disclosure relates to the area of textile articles and more particularly that of bras.
BACKGROUND
[0002] A bra classically comprises two cups for accommodating the breasts of a user, connected to one another by an intermediate part. A back is fixed to a lateral edge of its cup and comprises means for fixing it to the other back so that the bra is held in place on the user. Moreover, a bra strap connects the upper edge of its cup to the back and extends from the lateral edge of this cup.
[0003] Bras are known of the type provided with cups that each have a flexible shell conformed in such a manner as to have a concave, substantially hemispherical shape intended to surround the breasts of the user. However, the breasts of the user can have a substantially different morphology, which means that no bra is in reality perfectly adapted to the morphology of the two breasts. Furthermore, the morphology or the volume of the user's chest can vary substantially over time. The bra can then prove to be temporarily uncomfortable for its user.
SUMMARY
[0004] Therefore, the disclosure has the goal of proposing a bra without the previously cited disadvantages. In particular, the goal of the present disclosure is to propose a bra that can adapt perfectly to the morphology of the chest and that can also ensure a good hold of the chest without exerting excessive pressure on it.
[0005] The disclosure also relates to a bra comprising two cups connected to one another, intended to accommodate the breasts of a user and connected by their respective lateral edge to a part of the back and by their respective upper edge to a strap joining the corresponding part of the back, characterized in that each cup is constituted by an extensible piece of textile material in the form of a substantially planar sheet when the bra is not being worn, and that a major part of the sheet surface is cut along a plurality of notches of a limited length arranged all around an inner part of the sheet so as to form a reversibly deformable structure suitable for being deployed towards the front in a direction essentially transverse to the plane of the sheet under the effect of the weight of the breasts when the bra is being worn, causing this sheet to assume a volume conforming to the shape of the breasts and capable of supporting the breasts.
[0006] The present disclosure is therefore based on making a cup which is flat when the bra is not being worn assume a volume which is capable of deforming under the effect of the weight of the breasts substantially in one direction toward the front of the chest due to the presence of appropriate cuts made in the sheet of textile material constituting the cup. Once this has been done, the disclosure appropriates a technique of cutting and changing the volume of paper known under the name of “kirigami” in order to adapt it in a surprising and especially advantageous manner to the textile area and in particular to that of bras. In fact, due to an appropriate arrangement of the notches made flatly in the sheet of textile material constituting the cups, the latter, which are present in a substantially planar shape when the bra is not worn, “open up” under the effect of the weight of the breasts when the bra is worn in a favored one direction aimed to the front of the chest while surrounding the breasts in such a manner that the bra is applied more harmoniously and more comfortably to the user's bust, perfectly adjusted to the morphology of the user's breasts, which offers a holding without excessive stress on the chest.
[0007] Furthermore, the holding structure of the breasts openworked in this manner allows the skin to breathe freely, which increases even more the comfort of the wearer. In addition, by virtue of this construction which allows the cups to be flat in the non-worn state of the bra in accordance with the disclosure, the latter is made not very voluminous, for example, as compared to cups that are hot-molded and classically present a substantially and partially hemispheric concave shape. Finally, in addition to its technical function of holding the breasts, the openwork structure of the cups once they are deployed in the worn state of the bra creates a remarkable aesthetic effect which can vary as a function of the shape and the orientation selected for the notches.
[0008] The notches are advantageously arranged periodically in the sheet plane.
[0009] According to an embodiment at least a part of the notches can be arranged in accordance with a network of curved lines constituted by two symmetrical sets of lines extending respectively on each side of a longitudinal axis of a respective cup.
[0010] The sheet can advantageously comprise a succession of notches arranged according to a plurality of concentric, circular lines extending at least into the lower part of a respective cup.
[0011] The sheet advantageously comprises notches extending substantially vertically at least in the proximity of the upper edge of a respective cup.
[0012] The notches preferably have a rectilinear or substantially curved shape.
[0013] The notches advantageously have a maximum length comprised between 10 and 20 millimeters.
[0014] The notches are advantageously spaced at least 1 millimeter from each other, preferably from 1 to 5 millimeters.
[0015] According to an embodiment the sheet can have supplementary cuts made along an ornamental pattern and are advantageously arranged in the upper part of a respective cup and/or in its lower part.
[0016] The piece of textile material is preferably made of mono-layer or multi-layer knit fabric based on polyamide and elastane, advantageously with an elongation at 15 newtons comprised between 10% and 80% at least in one direction and with high responsiveness (e.g., springback).
[0017] The knit fabric preferably has a weight comprised between 250 and 400 g/m 2 .
[0018] According to an embodiment each cup is lined with a fine knit, elastic lining fixed peripherally on the cup.
[0019] The lining is advantageously made with a light mesh on the order of 60 g/m 2 with an elongation at 15 newtons at least equal to 130% in length and/or in width and equal to or greater than 240% at least in one direction.
BRIEF DESCRIPTION OF DRAWINGS
[0020] Other particularities and advantages of the disclosure will be apparent from a reading of the description given below of a particular embodiment of the disclosure given by way of a non-limiting example with reference made to the attached drawings in which:
[0021] FIG. 1 is a schematic view illustrating an example of a bra in conformity with the disclosure in a non-worn state;
[0022] FIGS. 2 to 4 show examples of sheets of textile material for forming the cups of the bra in accordance with the disclosure with different variants of embodiments of the notches;
[0023] FIG. 5 shows an example of a bra in conformity with the disclosure in the worn state.
DETAILED DESCRIPTION
[0024] FIG. 1 illustrates an example of a bra 1 in accordance with the disclosure. This bra comprises two cups 2 for accommodating the breasts of a user and are connected to one another on their inner side by a central intermediate part 3 . Each cup 2 has the shape of a sheet 21 of substantially planar textile material when the bra is not being worn. Furthermore, each cup 2 can be advantageously fixed in its lower part to a rigid underwiring 24 , while it is understood that the disclosure can also be applied to bras without underwiring that are called “soft”, or also to the bandeau type. In the example illustrated the underwiring 24 extends along a lower edge to a lateral edge 25 of a cup and comprises fixation means (not shown) on the other back part. A strap 5 joins the upper edge 26 of a cup 2 to the corresponding part of back 4 .
[0025] As schematically illustrated in FIG. 1 , each sheet 21 of textile material, that can be a mono-layer or multi-layer (a complex of several materials assembled by thermal adhesion, for example) sheet, comprises in the sheet plane over a major part of its surface a plurality of notches 22 or slots, substantially linear, traversing the entire thickness of the sheet 21 and arranged entirely around an inner part 23 of the sheet 21 free of notches and preferably with a discoidal (circular surface) shape or ellipsoidal (oval surface) shape. The inner part 23 free of notches 22 preferably forms a substantially central part of the sheet constituting the cup and can be advantageously off-center toward the inner side of the cup (toward the central part of the bra) so as to achieve an effect of bringing the breasts closer to one another. Furthermore, the surface occupied by the inner part 23 free of notches 22 is a function of the selected dimension of the notches 22 . Therefore, the smaller the notches, the greater the surface occupied by the inner part 23 .
[0026] The notches 22 , by virtue of their shape, dimension and appropriate orientation in the sheet plane, are intended to allow an extension of the sheet 21 in a direction substantially transverse to the sheet plane, that is, in the direction pointing to the front of the chest while preserving a certain rigidity of the sheet in directions transverse to the chest under the effect of the weight of the breasts when the bra is worn. In other words, the sheet 21 openworked in this manner by the notches 22 constitutes a reversibly deformable holding structure suitable for being deployed to the front, permitting and ensuring a substantially hemispheric change of the volume of a respective cup of the bra in the direction pointing to the front of the chest under the effect of the breasts when the bra is worn, and suitable for being able to be folded in order to return to a substantially planar configuration when the bra is not being worn.
[0027] The shape of the sheet depends on the shape and the size of the bra for which it is provided but it is preferably in an elongated, substantially elliptical shape and more particularly in the shape of a tear with a major axis extending between the upper edge of the cup and the lower edge of a respective cup, for example, comprised between 100 mm and 160 mm, and a minor axis extending between the lateral edges of a respective cup, for example comprised between 50 mm and 130 mm.
[0028] The notches 22 preferably have a maximum length comprised between approximately 10 mm and 20 mm, preferably approximately 15 mm and are arranged periodically in the plane of the sheet 21 , preferably following a network of lines extending all around the inner part 23 of the sheet 21 . In a general manner the notches 22 are spaced among themselves in all directions of the sheet plane by at least 1 millimeter, preferably from 1 mm to 5 mm and advantageously 3 mm.
[0029] In addition to the shape and the arrangement of the notches 22 in the plane of the sheet 21 , the textile material of the sheet also greatly influences the opening and the change in volume of the latter under the effect of the weight of the breasts when the bra is worn. The sheet 21 of textile material is advantageously made of mono-layer or multi-layer (several knit fabrics assembled in a complex by thermal adhesion, for example) knit fabrics based on polyamide and elastane (preferably approximately 40% by weight elastane relative to the total weight of the knit fabric). It advantageously has an elongation at 15 newtons comprised between 10% and 80% at least in one direction. The specific weight of the knit fabric is advantageously comprised between 250 and 400 g/m 2 . Furthermore, it advantageously has a very high responsiveness (e.g., springback), indicated by the characteristics in terms of force up to 30% of elongation preferably comprised between 700 and 900 cN. Due to this fact the material perfectly accompanies the morphology of the breasts and favors the return of the sheet 21 into a substantially planar configuration when the bra is not worn.
[0030] Different variants of the arrangement of the notches 22 will now be described according to different patterns in the plane of the sheet 21 when flat, allowing the obtention of an extension of the sheet 21 in a direction aimed at the front of the chest for a change in volume of the sheet 21 in a substantially hemispheric shape suitable for holding the breast when the bra is being worn.
[0031] In the particular embodiment illustrated in FIG. 2 the majority of the notches 22 is arranged in the plane of the sheet 21 in accordance with a network of curved lines, preferably equidistant and parallel to each other, constituted by two symmetrical sets of lines extending respectively on each side of a longitudinal axis X passing through the substantially central inner part 23 of the sheet 21 .
[0032] In the lower median part of the sheet 21 of textile material constituting a respective cup 2 the plurality of successive notches 22 arranged in line advantageously form a plurality of concentric circular lines extending from the edges of the cup 2 and approaching the substantially central inner part 23 of the sheet 21 .
[0033] Furthermore, the sheet 21 advantageously comprises vertical notches 22 at the top part of a respective cup 2 at least in the proximity of the upper edge 26 of the cup which can be aligned vertically in the form of several vertical lines extending from the substantially central inner part 23 toward the upper edge 26 of the cup. This vertical arrangement of the notches in the respective top part of a cup 2 is preferable in order to allow the cup to rest substantially flat in this upper part after extension when the bra is worn.
[0034] This particular embodiment of the cups is illustrated in the worn state of the bra 1 in FIG. 5 . When the bra 1 is worn by a user, the notches 22 open under the effect of the weight of the breasts, allowing the sheet 21 to deploy toward the front in a direction substantially transverse to the plane of the sheet 21 , conforming to the shape of the breasts and the textile material between the notches 22 which are therefore open extends, forming a network of crossed lines 220 constituted by the material between the notches 22 suitable for maintaining the breasts and extending from the edges of the cup toward the central zone 23 projected forward under the effect of the weight of the breasts.
[0035] According to the variant of FIG. 3 , in the upper median part of the sheet 21 the notches 22 constitute two sets of oblique lines arranged in distinct and symmetrical directions in the plane of the sheet 21 relative to the axis X, extending radially from the substantially central inner part 23 toward the edges of a respective cup 2 . It turns out that this arrangement of the notches 22 in the upper median part of the sheet 21 allows the obtention of a deforming configuration of the cups 2 that is particularly adapted for the sides of the bra, that is, on the side of the lateral edge 25 of the cups whereas the arrangement of the notches 22 in the upper median part of the sheet 21 such as described with reference made to FIG. 2 is particularly adapted for the center of the bra, that is, on the inner side of the cups.
[0036] Also, the variant the FIG. 4 illustrates a combination of two previous embodiments and concerns the arrangement of the notches 22 in the upper median part of the sheet 21 which repeats the arrangement of FIG. 3 on the side of the lateral edge 25 of the respective cup 2 and that of FIG. 2 on the inner side of the cup 2 .
[0037] However, whatever the embodiment is, it is advisable to arrange the vertical notches in the upper part of a respective cup 2 as explained referring to FIG. 2 . The shape of the notches is preferably substantially curved, which notches are arranged along curved lines and rectilinear in vertical notches or those arranged along oblique lines. Furthermore, supplementary cuts made in accordance with an ornamental pattern can be advantageously arranged in the upper part of the cup and/or in the substantially central lower part 23 to the extent that when arranged in this manner, such cups do not open very much when the bra is worn.
[0038] According to an embodiment each cup 2 can be lined with a fine, knit elastic lining (not shown) provided for being applied preferably on the entire outer face of a respective cup 2 and which is preferably fixed peripherally to the outer face of a respective cup 2 . As a variant the cup can be lined with the fine elastic lining on the side of its inner face. According to an exemplary embodiment such a lining can be made of simple material, preferably with a light mesh on the order of 60 g/m 2 and has an elongation at 15 newtons at least equal to 130% (comprised between 180% and 360% and beyond) in length and/or in width and equal to or greater than at least 240% in one of the two directions. Furthermore, it has a high responsiveness (e.g., springback), advantageously allowing it to not “go baggy” after extension.
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The disclosure relates to a bra comprising two cups for accomodating the breasts of a user in which each cup is constituted by a piece of extensible textile material in the form of a substantially planar sheet when the bra is not worm, wherein a major part of the surface of the sheet is cut along a plurality of notches with a limited length arranged all around an inner part of the sheet in such a manner as to form a reversibly deformable structure suitable for being deployed to the front in a direction substantially transversal to the plane of the sheet under the effect of the weight of the breasts when the bra is being worn, causing this sheet to assume a volume conforming to the shape of the breasts and capable of supporting the breasts.
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